Gilera Nexus 500 Workshop Manual
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Gilera Nexus 500 Workshop Manual

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WORKSHOP MANUAL
633309
Nexus 500

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Summary of Contents for Gilera Nexus 500

  • Page 1 WORKSHOP MANUAL 633309 Nexus 500...
  • Page 2 The descriptions and illustrations given in this publication are not binding. While the basic specifications as described and illustrated in this manual remain unchanged, PIAGGIO-GILERA reserves the right, at any time and without being required to update this publication beforehand, to make any changes to components, parts or accessories, which it considers necessary to improve the product or which are required for manufacturing or construction reasons.
  • Page 3 This workshop manual has been drawn up by Piaggio & C. Spa to be used by the workshops of Piaggio- Gilera dealers. This manual is addressed to Piaggio service mechanics who are supposed to have a basic knowledge of mechanics principles and of vehicle fixing techniques and procedures. Any important changes made to the vehicles or to specific fixing operations will be promptly reported by updates to this manual.
  • Page 5 INDEX OF TOPICS CHAR HARACTERISTICS TOOL OOLING MAIN AINTENANCE ELE SYS LECTRICAL SYSTEM ENG VE NGINE FROM VEHICLE NGINE INJEC NJECTION SUSP USPENSIONS BRAK SYS RAKING SYSTEM COOL SYS OOLING SYSTEM CHAS HASSIS PRE DE DELIVERY TIME...
  • Page 7 INDEX OF TOPICS CHAR HARACTERISTICS...

  • Page 8: Safety Rules

    Nexus 500 Characteristics This section describes the general specifications of the vehicle. Rules This section describes general safety rules for any maintenance operations performed on the scooter. Safety rules Should it be necessary to keep the engine running while servicing, make sure that the area or room is well ventilated, and use special exhaust fans, if required.
  • Page 9 Nexus 500 Characteristics Vehicle identification Characteristic Engine prefix: M351M Characteristic Chassis prefix: ZAPM35100 Dimensions and mass WEIGHT Specification Desc./Quantity Dry weight 199 kg Width 765 mm Length 2090 mm Wheel base 1515 mm Saddle height 780 mm Height 1045 mm...

  • Page 10: Electrical System

    Nexus 500 Characteristics Specification Desc./Quantity Timing system Single overhead camshaft with integrated tone wheel, control from flywheel side chain, 4 valves and automatic start-up valve lifting device. Valve clearance: intake: 0.15 mm (when cold) Valve clearance: exhaust 0.15 mm (when cold)
  • Page 11 Nexus 500 Characteristics Specification Desc./Quantity Spark plug CHAMPION RG6YC Battery Dry-cell lead-acid battery, 12V-14Ah Generator Three-phase alternating current Frame and suspensions CHASSIS AND SUSPENSIONS Specification Desc./Quantity Chassis Welded tubular steel chassis with stamped sheet reinforcements Front suspension Hydraulic telescopic fork with diameter 41 mm stems Max.

  • Page 12: Wheels And Tyres

    Nexus 500 Characteristics Wheels and tyres WHEELS AND TYRES Specification Desc./Quantity Rims in light alloy: Front 3.50 x 15" Rims in light alloy: Rear 4.50 x 14" Tyres: Front Bridgestone 120/70-R15" Battlax TH01 - Tubless Tyres: Rear Bridgestone 160/60-R14" Battlax TH01 - Tubless Tyre pressure (cold) front 2.1 bar...
  • Page 13 Nexus 500 Characteristics Name Torque in Nm Plastic protection retaining screw 5 - 6 Coupling for oil on the integral braking system 16 ÷ 20 pump Coupling on the integral braking system device 20 ÷ 25 (from the pump) Front brake calliper - integral braking system de- 20 ÷...
  • Page 14 Nexus 500 Characteristics Name Torque in Nm Exhaust / intake head fixing nuts: 10 - 12 Head lubrication control jet 5 - 7 coolant temperature sensor: 10 - 12 injector fixing screw 3 ÷ 4 Counterweight screw 7 ÷ 8.5...

  • Page 15: Assembly Clearances

    Nexus 500 Characteristics Name Torque in Nm Supporting screws with bulkhead 0.3 - 0.4 Minimum oil pressure sensor 12 ÷ 14 Water pump impeller 4 ÷ 5 LUBRICATION Name Torque in Nm Oil pump cover screws 0.7 ÷ 0.9 Screws fixing oil pump to the crankcase...
  • Page 16 Nexus 500 Characteristics Specification Desc./Quantity 43 mm CATEGORIES OF COUPLING Name Initials Cylinder Piston Play on fitting Cylinder Piston 91.990 - 91.997 91.954 - 91.961 0.029 - 0.043 Cylinder Piston 91.997 - 92.004 91.961 - 91.968 0.029 - 0.043 Cylinder Piston 92.004 - 92.011...
  • Page 17 Nexus 500 Characteristics TYPE A Specification Desc./Quantity Centre to centre distance of the gears without 76.937 ÷ 76.867 clearance Centre to centre distance on the crankcase 77.022 ÷ 76.992 TYPE B Specification Desc./Quantity Centre to centre distance of the gears without 76.907 ÷...
  • Page 18 Nexus 500 Characteristics Specification Desc./Quantity 0.10 mm AXIAL CLEARANCE BETWEEN CRANKSHAFT AND CONNECTING ROD Name Description Dimensions Initials Quantity Transmission-side 0.8 ± 0.025 D= 0.20 - 0.40 shoulder Transmission-side 19.6 + 0.050 D= 0.20 - 0.40 half-shaft Connecting rod 22 0.10-0.15 D= 0.20 - 0.40...
  • Page 19 Nexus 500 Characteristics Slot packing system Shimming system for limiting the compression ratio Rc = 10.5 : 1 DISTANCE "A" IS A PROJECTION OR RECESS VALUE OF THE PISTON TOP FROM THE CYL- INDER PLANE. DISTANCE "A" ALLOWS THE THICKNESS OF THE GASKET TO BE DETERMINED THAT HAS TO BE FITTED TO THE CYLINDER HEAD IN ORDER TO RESTORE THE COMPRESSION RATIO.
  • Page 20 Nexus 500 Characteristics Product Description Specifications AGIP CITY HI TEC 4T Engine oil SAE 5W-40, API SL, ACEA A3, JASO MA Synthetic oil AGIP BRAKE 4 Brake fluid FMVSS DOT 4 Synthetic fluid SPECIAL AGIP PERMANENT coolant Monoethylene glycol-based anti-...
  • Page 21 INDEX OF TOPICS TOOL OOLING...
  • Page 22 Nexus 500 Tooling TOOLS Stores code Description 001330Y Tool for fitting steering seats 001467Y002 Driver for OD 73 mm bearing 001467Y006 Pliers to extract 20 mm bearings 001467Y007 Driver for OD 54 mm bearing 001467Y008 Pliers to extract 17 mm ø bear-...
  • Page 23 Nexus 500 Tooling Stores code Description 001467Y031 Bell 001467Y034 Extraction pliers for ø 15 mm bearings 001467Y035 Belle for OD 47-mm bearings 002465Y Pliers for circlips 006029Y Punch for fitting fifth wheel seat on steering tube 020004Y Punch for removing fifth wheels...
  • Page 24 Nexus 500 Tooling Stores code Description 020055Y Wrench for steering tube ring nut 020150Y Air heater support 020151Y Air heater 020193Y Oil pressure gauge 020201Y Spacer bushing driving tube 020262Y Crankcase splitting strip 020306Y Punch for assembling valve seal rings...
  • Page 25 Nexus 500 Tooling Stores code Description 020329Y MityVac vacuum-operated pump 020330Y Stroboscopic light for timing con- trol 020331Y Digital multimeter 020333Y Single battery charger 020334Y Multiple battery charger TOOL - 5...
  • Page 26 Nexus 500 Tooling Stores code Description 020335Y Magnetic support for dial gauge 020357Y 32 x 35 mm adaptor 020358Y 37x40-mm adaptor 020359Y 42x47-mm adaptor 020360Y Adaptor 52 x 55 mm 020364Y 25-mm guide 020376Y Adaptor handle 020382Y012 bush (valve removing tool)
  • Page 27 Nexus 500 Tooling Stores code Description 020412Y 15 mm guide 020424Y Driven pulley roller casing fitting punch 020431Y Valve oil seal extractor 020434Y Oil pressure control fitting 020439Y 17 mm guide TOOL - 7...
  • Page 28 Nexus 500 Tooling Stores code Description 020444Y Tool for fitting/ removing the driv- en pulley clutch 020456Y Ø 24 mm adaptor 020458Y Puller for lower bearing on steer- ing tube 020459Y Punch for fitting bearing on steer- ing tube 020460Y...
  • Page 29 Nexus 500 Tooling Stores code Description 020468Y Piston fitting ring 020469Y Reprogramming kit for scooter diagnosis tester 020470Y Pin retainers installation tool 020471Y Pin for countershaft timing 020472Y Flywheel lock wrench TOOL - 9...
  • Page 30 Nexus 500 Tooling Stores code Description 020474Y Driving pulley lock wrench 020475Y Piston position checking tool 020476Y Stud bolt set 020478Y Punch for driven pulley roller cas- 020479Y Countershaft lock wrench 020480Y Petrol pressure check set TOOL - 10...
  • Page 31 Nexus 500 Tooling Stores code Description 020481Y Control unit interface wiring 020482Y Engine support 020483Y 30 mm guide 020512Y Piston fitting fork 020527Y Engine support base 020604Y011 Fitting adapter 020565Y Flywheel lock calliper spanner TOOL - 11...
  • Page 32 Nexus 500 Tooling Stores code Description 020623Y Pre-service gas extraction set 020625Y Kit for sampling gas from the ex- haust manifold 494929Y Exhaust fumes analyser TOOL - 12...
  • Page 33 INDEX OF TOPICS MAIN AINTENANCE...

  • Page 34: Maintenance Chart

    Nexus 500 Maintenance Maintenance chart Adequate maintenance is fundamental to ensuring long-lasting, optimum operation and performance of your vehicle. To this end, a series of checks and maintenance operations (at the owner's expense) have been sug- gested, which are included in the summary table on the following page. Any minor faults should be reported without delay to an Authorised Service Centre or Dealer without waiting until the next scheduled service to solve it.
  • Page 35 Nexus 500 Maintenance Action Electrical system and battery - check Vehicle and brake test - road test AFTER 6,000 KM OR 12 MONTHS Action Engine oil - replacement Hub oil - level check Spark plug / electrode gap - check...
  • Page 36 Nexus 500 Maintenance Action Spark plug / electrode gap - check Air filter - change Engine oil - change Valve clearance - check Base vent - check Variable speed rollers - replacement Driving belt - check Coolant level - check...
  • Page 37 Nexus 500 Maintenance Action Coolant level - check Brake fluid level - check Electrical system and battery - check Tyre inflation and wear - Check Vehicle and brake test - road test AFTER 36,000 KM 365' Action Engine oil - replacement...
  • Page 38 Nexus 500 Maintenance Action Brake control levers - greasing Transmission elements - lubrication Brake fluid level - check Safety locks - check Suspensions - check Electrical system and battery - check Headlight - adjustment Tyre inflation and wear - Check...

  • Page 39: Spark Plug

    Nexus 500 Maintenance Spark plug Check and replacement CAUTION THE SPARK PLUG MUST BE REMOVED WITH COLD ENGINE. THE SPARK PLUG SHOULD BE CHECKED EVERY 6,000 KM AND RE- PLACED EVERY 12,000 KM. THE USE OF NON- CONFORMING IGNITION CONTROL UNITS...
  • Page 40 Nexus 500 Maintenance Check Check the oil in the rear hub. Characteristic Rear hub oil Capacity approximately 250 cc To check the rear hub oil level, proceed as follows: - Park the scooter on flat ground resting on its centre stand.

  • Page 41: Air Filter

    Nexus 500 Maintenance - Unscrew the oil drainage plug and drain out all the oil. - Tighten the drainage plug with its gasket and re- fill. - Tighten the oil filler plug. Characteristic Rear hub oil Capacity approximately 250 cc...

  • Page 42: Engine Oil

    Nexus 500 Maintenance - Replace the air filter and reassemble the various components, reversing the removal procedure. - An inspection and possible cleaning (with com- pressed air) of the air filter is scheduled every 6000 km in any case. - The air jet must be directed from the inside to the outside of the filter (i.e.

  • Page 43: Engine Oil Filter

    Nexus 500 Maintenance Check This operation must be carried out with the engine cold and following the procedure below: 1) Rest the scooter on the central stand and on a flat ground. 2) Unscrew the cap/dipstick "A", dry it with a clean cloth and reinsert it, screwing it thoroughly.
  • Page 44 Nexus 500 Maintenance - Remove and clean the mesh pre-filter of the drain cap with compressed air. - Use a belt spanner for filters to remove cartridge filter "C". - Make sure the pre-filter and drain cap O-rings are in good condition.

  • Page 45: Checking The Valve Clearance

    Nexus 500 Maintenance Oil pressure warning light Warning light (low oil pressure) The vehicle is equipped with a warning light on the instrument panel that lights up when the key is turned to the "ON" position. However, this light should switch off once the engine has been star- ted.
  • Page 46 Nexus 500 Maintenance CAUTION THIS OPERATION MUST BE CARRIED OUT WHEN THE ENGINE IS COLD. - Remove the water pump cover as indicated in the figure by loosening the 6 retaining screws. - Proceeding as described in chapter "Engine", partially drain the system and overhaul the pump.

  • Page 47: Braking System

    Nexus 500 Maintenance FOR THE REPLACEMENT OF THE COOLANT AND THE FLUSHING OF THE SYSTEM, SEE CHAPTER COOLING SYSTEM. Braking system Level check - Rest the scooter on a flat ground and on the cen- tral stand. - Remove the brake pump cover as shown in the figure.

  • Page 48: Headlight Adjustment

    Nexus 500 Maintenance - Remove the tank cap by loosening its two screws, remove the gasket and top up the level, using only the prescribed fluid without exceeding the maximum level. CAUTION MAKE SURE THE BRAKE FLUID DOES NOT GET INTO YOUR EYES OR ON YOUR SKIN OR CLOTHES.
  • Page 49 Nexus 500 Maintenance - Otherwise, adjust the right headlight by the screw shown in the figure, which can be accessed by re- moving the front shield connecting member. N.B. THE ABOVE PROCEDURE COMPLIES WITH THE EUROPEAN STANDARDS REGARDING MAXIMUM AND MINIMUM HEIGHT OF LIGHT BEAMS.
  • Page 50 Nexus 500 Maintenance MAIN - 18...
  • Page 51 INDEX OF TOPICS ELE SYS LECTRICAL SYSTEM...
  • Page 52 Nexus 500 Electrical system ELECTRICAL SYSTEM Specification Desc./Quantity Left headlight for sidelight N° 1 12V-55W bulb Front left direction indicator 1 bulb 12V - 10W Rear brake stop button Left electric control Front fuse holder terminal board Fuse Fuse 7,5 A...
  • Page 53 Nexus 500 Electrical system Specification Desc./Quantity Battery 12V - 14 Ah Helmet compartment lighting button Indicator lights N° 4 12V-1.2W bulbs (1-Emerg. flash. light; 2-Taillight indicator; 3-High beam indicator; 4-Engine stop indicator) Tilting sensor Fuel pump Diagnostic socket Fuel Gauge...
  • Page 54 Nexus 500 Electrical system Components arrangement Diagnostic socket In order to access the diagnostic socket, remove the supports of the passenger footrest. Overturn sensor In order to access the overturn sensor, remove the central union. During assembly, observe the installation direction shown in the figure.
  • Page 55 Nexus 500 Electrical system Saddle opening ECU remote control. Resetting of the remote control Electronic control unit ECU In order to access the immobilizer control unit, re- move the upper shield back plate. In order to access the connector, remove the wind-...
  • Page 56 Nexus 500 Electrical system Relays and diode group In order to access the relays and the diode group, remove the upper shield back plate. Specification Desc./Quantity DIODE UNIT ELECTRIC FAN REMOTE CONTROL SWITCH ENGINE STOP REMOTE CONTROL SWITCH CONTROL UNIT REMOTE CONTROL SWITCH Voltage regulator To access the voltage regulator.
  • Page 57 Nexus 500 Electrical system Ignition IGNITION Specification Desc./Quantity Instrument panel HV coil Stoplight switches Start up button Fuse 7,5 A Control unit remote control switch Stop light Fuse Diode Engine stop remote control switch Starter motor Engine stop indicator Remote starter switch...
  • Page 58 Nexus 500 Electrical system Specification Desc./Quantity Engine stop switch Diode Key switch contacts Key switch contacts Battery 12V - 14 Ah Fuse 10 A Fuse Fuse 7,5 A Voltage regulator EMS controller Decoder Fuse Tilting sensor Headlights and automatic starter section...
  • Page 59 Nexus 500 Electrical system LIGHT AND FLASHING LIGHT BULBS SECTION Specification Desc./Quantity Hazard indicator light management electron- Hazard indicator N° 4 flashing light bulbs Fuse 7,5 A Light switch Upper beam Key switch contacts Fuse 7,5 A Passing Dipped beam...
  • Page 60 Nexus 500 Electrical system Battery recharge and starting BATTERY RECHARGE AND STARTING Specification Desc./Quantity Key switch contacts Fuse 7.5 A Stoplight switches Stop light Starter motor Key switch contacts Start up button Remote starter switch Fuse Diode Fuse 7,5 A...
  • Page 61 Nexus 500 Electrical system Level indicators and enable signals section SAFETY SWITCHES AND LEVEL INDICATOR SECTION Specification Desc./Quantity Tachometer Instrument panel Fuel level sender Oil pressure sensor Cooling fluid temperature sensor Wheel RPM sensor Saddle opening receiver Saddle opening actuator...
  • Page 62 Nexus 500 Electrical system Specification Desc./Quantity Diode Engine stop switch Stand switch Engine stop indicator Key switch contacts Key switch contacts Fuse 7.5 A Fuse Battery 12V - 14 Ah Voltage regulator Anti-tilting sensor Checks and inspections Battery recharge circuit The recharge system is provided with a three phase alternator with permanent flywheel.
  • Page 63 Nexus 500 Electrical system BEFORE CARRYING OUT THE CHECK, MAKE SURE THAT THE BATTERY IS IN GOOD WORK- ING ORDER. 1) Place the vehicle on its centre stand 2) With the battery correctly connected to the circuit, place the tester terminals between the battery terminals..
  • Page 64 Nexus 500 Electrical system Fuses The electric system is equipped with: - Six fuses «A» located inside the right side. - 5 fuses «B» in the un- dersaddle compart- ment. - A 30A fuse (main fuse), next to the bat- tery on the left side;...
  • Page 65 Nexus 500 Electrical system The tables show the po- sition and the charac- teristics of the fuses present in the vehicle FUSE HOLDER A (HELMET COMPART- MENT) Specification Desc./Quantity Not used Number plate light - Position lights - In- strument unit light...

  • Page 66: Dashboard

    Nexus 500 Electrical system Dashboard The digital display has two service symbols: SERVICE (Service coupon): The lamp should come on after reaching 1000 km or 1 year after initial activation, then every 6000 km or 1 year after the last activation.
  • Page 67 Nexus 500 Electrical system - The emergency control can only be enabled and disabled with key set to «ON» and must continue to operate with key set to «OFF». - The «engine disabled» indicator is activated by the side stand switch and by the emergency switch on the right side of the handlebar.
  • Page 68 Nexus 500 Electrical system The value is calculated on the basis of the trip kilometre reading. 4. Momentary consumption The fuel symbol and km/h or mph appear. 5. Range The fuel icon appears. If the range drops below 40 km, the symbol appears automatically and flashes for 60 seconds.
  • Page 69 Nexus 500 Electrical system Set the hours with the button "ODO/SET". Press button "CLOCK" again and the figures showing the minutes start to flash. Set the minutes with the «ODO/SET» button. Press the «CLOCK» button again to start the clock moving normally.
  • Page 70 Nexus 500 Electrical system 3) Constant current battery charge mode -Charge current equal to 1/10 of the nominal capacity of the battery - Charge time: 5 h Specific tooling 020333Y Single battery charger 020334Y Multiple battery charger Cleaning the battery The battery should always be kept clean, especially on its top side, and the terminals should be coated with Vaseline.
  • Page 71 Nexus 500 Electrical system - After carrying out the operations above, install the battery on the scooter, observing the connections described in point 3) of paragraph "Battery re- charge". Specific tooling 020333Y Single battery charger 020334Y Multiple battery charger 1 Keep the pipe in vertical position...
  • Page 72 Nexus 500 Electrical system The battery should always be kept clean, especially on its top side, and the terminals should be coated with Vaseline. CAUTION NEVER USE FUSES WITH A CAPACITY HIGHER THAN THE RECOMMENDED CAPACITY. USING A FUSE OF UNSUITABLE RATING MAY SERIOUSLY DAMAGE THE VEHICLE OR EVEN CAUSE A FIRE.
  • Page 73 Nexus 500 Electrical system If other voltages are measured or there is no alternation, replace the tone wheel. Connectors Layout of the system-side connectors and the con- nectors on the electronic control unit. Specification Desc./Quantity Throttle potentiometer power supply +5 V...
  • Page 74 Nexus 500 Electrical system Specification Desc./Quantity Stepper motor Stepper motor Sensor power supply Control unit negative Stepper motor Stepper motor Continuous power supply (positive) Seat opening receiver RECEIVER CONTROL UNIT FOR SADDLE OPENER Specification Desc./Quantity Radio aerial Actuator positive output 1...
  • Page 75 Nexus 500 Electrical system Specification Desc./Quantity Base power supply (positive) Negative Electronic control unit EMS (serial) Continuous power supply (positive) Immobilizer aerial Engine rev. sensor REV SENSOR Specification Desc./Quantity Male Female Shielding Dashboard The instrument panel is provided with two connec- tors ("A"...
  • Page 76 20. Emergency warning flashers Connector "B" KEY: 1. Rpm indicator (D) 2. Rpm indicator (B) 3. - 4. - 5. ICP/ID "NEXUS 500" 6. ICP/ID "NEXUS 250" 7. Rpm indicator (C) 8. Rpm indicator (A) 9. - 10. - 11. - 12.

  • Page 77: Battery Replacement

    Nexus 500 Electrical system Analogue odometer ANALOGUE ODOMETER Specification Desc./Quantity STEPPER MOTOR A STEPPER MOTOR B STEPPER MOTOR C STEPPER MOTOR D Remote seat opening The vehicle is equipped with a remote control to open the saddle. This remote control is supplied together with the keys and at the manufacturing stage, it has been programmed to work together with the ECU that control the opening device.
  • Page 78 Nexus 500 Electrical system Zeroing - Remove the front shield to gain access to the re- ceiver control unit / seat opener controller. - Within the electrical wiring harness there are two cables, one black (ground) and one black/blue coming from pin 3 of the control unit.
  • Page 79 INDEX OF TOPICS ENG VE NGINE FROM VEHICLE...
  • Page 80 Nexus 500 Engine from vehicle Exhaust assy. Removal - Loosen the two mountings of the exhaust mani- fold at the cylinder head. Remove the screw indicated in the photograph. - Loosen the screw shown in the figure so as to loosen the muffler strap and remove the whole muffler.
  • Page 81 Nexus 500 Engine from vehicle - Perform the operations for removal but in reverse order according to the locking torque indicated in «Specifications» Chapter. CAUTION PAY PARTICULAR ATTENTION TO POSITIONING THE THROTTLE COMMAND TRANSMISSION PROPERLY. Check that with valve in abutment against the register there is a small clearance.
  • Page 82 Nexus 500 Engine from vehicle ENG VE - 4...
  • Page 83 INDEX OF TOPICS NGINE...

  • Page 84: Automatic Transmission

    Nexus 500 Engine This section describes the operations to be carried out on the engine and the tools to be used. Automatic transmission Transmission cover - Using a screwdriver, remove the driven pulley axle cover near the bottom of the cap.
  • Page 85 Nexus 500 Engine - Remove the four M8 screws. - Remove the transmission cover. - Check that the bearing rotates freely, otherwise replace it. - Loosen the 4 fastening screws - Extract the outside plastic transmission cover. Air duct - Remove the transmission cover.
  • Page 86 Nexus 500 Engine Air duct filter - Remove the external air conveyor. - Unscrew the 2 fastening screws shown in the fig- ure to remove the conveyor filter. Removing the driven pulley shaft bearing - Remove the transmission cover. - Remove the seeger ring.
  • Page 87 Nexus 500 Engine Refitting the driven pulley shaft bearing - Heat the transmission cover interior using the heat gun. N.B. BE CAREFUL NOT TO OVERHEAT THE COV- ER AS THIS WOULD DAMAGE THE OUTSIDE PAINTED SURFACE. Specific tooling 020151Y Air heater - Place the bearing onto the special tool with a little grease to prevent it from coming out.

  • Page 88: Inspecting The Clutch Drum

    Nexus 500 Engine - Check that the roller does not show signs of wear and that it turns freely. - Loosen the retaining bolt using a 13 mm spanner. - Remove the complete roller with bearing. N.B. IF THE ROLLER DOES NOT ROTATE FREELY, REPLACE THE COMPLETE ROLLER.

  • Page 89: Removing The Clutch

    Nexus 500 Engine 160.2 mm Removing the clutch - To remove the clutch with the driven pulley it is necessary to use the special tool; - Arrange the tool with the mean pins screwed in position "E" on the inside;...
  • Page 90 Nexus 500 Engine Removing the driven half-pulley bearing - Check that the bushing is free from wear and damage; otherwise replace the fixed driven half- pulley. - Remove the lock ring using pliers. - Using the special tool inserted through the roller bearing, pull out the ball bearing.
  • Page 91 Nexus 500 Engine Inspecting the driven fixed half-pulley - Check that the belt contact surface is free from wear. - Measure the outer diameter of the pulley bushing. Characteristic Minimum admissible diameter 49.96 mm Standard diameter: 49.965 mm Inspecting the driven sliding half-pulley - Check that the belt contact surface is free from wear.

  • Page 92: Refitting The Driven Pulley

    Nexus 500 Engine Specific tooling 020478Y Punch for driven pulley roller casing 001467Y002 Driver for OD 73 mm bearing - Install a new ball bearing using the special tool. Specific tooling 020376Y Adaptor handle 020477Y Adaptor 37 mm 020363Y 20 mm guide - Insert the seeger lock ring.
  • Page 93 Nexus 500 Engine Soap-based lithium grease containing NLGI 2 Molybdenum disulphide; ISO-L-XBCHB2, DIN KF2K-20 Inspecting the clutch spring - Measure the length of the spring, while it is re- laxed. Characteristic Standard length: 125.5 mm Admissible limit after use: 120 mm - Check the thickness of the clutch mass friction material.
  • Page 94 Nexus 500 Engine Refitting the clutch Bell assembly - Install the bell and the spacer. - Prepare the special tool as for removal; - Preassemble the driven pulley unit with the drive belt according to its direction of rotation; - Insert the driven pulley unit, the spring with sheath and clutch into the tool.

  • Page 95: Removing The Driving Pulley

    Nexus 500 Engine Refitting the driven pulley - Install the driven pulley assembly with belt. Drive-belt - Check that the driving belt is not damaged. - Check the width of the belt. Characteristic Minimum width: 25 mm Standard width: 26.2 mm...
  • Page 96 Nexus 500 Engine - First install the lock ring of the special tool onto the pulley so that the splines are completely en- gaged. - Then, insert the tool so as to insert the stud bolts on the ring into the holes obtained onto the tool itself.
  • Page 97 Nexus 500 Engine Minimum admissible diameter Ø 29.95 mm Standard diameter: Ø 29.959 mm - Check that the rollers are not damaged or worn. Characteristic Minimum admissible diameter Ø 24.5 mm Standard diameter: Ø 24.9 mm - Check the guide shoes for the variator back-plate are not worn.
  • Page 98 Nexus 500 Engine - Assembly the half-pulley with the roller contrast plate and sliding blocks. - Insert the half-pulley on the crankshaft. - Insert the spacer bushing. Installing the fixed driving half-pulley - Insert the spacer. - Install the fixed driving half-pulley and check that it is in contact with the spacer and with the guide bushing of the moving driving pulley.
  • Page 99 Nexus 500 Engine - Remove the flat washer and the spring washer as shown in the figure. - Insert the nut in the original position (nut side in contact with the belleville washer). - Turn the central pulley nut to horizontally align the holes and install the special tool.
  • Page 100 Nexus 500 Engine Refitting the transmission cover - Ensure the correct installation on the crankcase of the 2 centring dowels. - Insert the transmission cover with the bearing and install the relevant retainers. - Lock the four M8 retainers. Locking torques (N*m) M8 retainers for transmission cover 23 - 26 - Lock the 7 M6 retainers.
  • Page 101 Nexus 500 Engine DAMAGE THE HEXAGON OBTAINED ON THE SHAFT OR BREAK THE BUSH ITSELF. Locking torques (N*m) Driven pulley nut 92 - 100 - Install the driving pulley shaft cover, positioning the tooth gap on the lower part with the reference mark on the transmission crankcase.
  • Page 102 Nexus 500 Engine Removing the wheel axle - Remove the countershaft. - Remove the wheel axis complete with gear. Removing the hub bearings - Check all bearings (wear, clearance and noise). In case of anomalies, proceed as follows. To remove the gear shaft bearing on the engine crankcase, use the following parts.
  • Page 103 Nexus 500 Engine - Support the hub cover using the column kit. - Pull out the bearing using the special tool. Specific tooling 020476Y Stud bolt set 001467Y006 Pliers to extract 20 mm bearings 001467Y007 Driver for OD 54 mm bearing...
  • Page 104 Nexus 500 Engine Removing the driven pulley shaft bearing - If you have to remove the driven pulley shaft, the relevant bearing and the oil guard, remove the transmission cover and the clutch unit as descri- bed in the Automatic transmission chapter.
  • Page 105 Nexus 500 Engine Inspecting the hub cover - Check that the mounting surface is not damaged or deformed. - Check the bearing bearings. In case of faults, replace the hub cover. Refitting the driven pulley shaft bearing - Heat the crankcase using the heat gun.
  • Page 106 Nexus 500 Engine - Heat the gear shaft bearing seat on the crank- case. - Insert the gear shaft bearing in the upper crank- case seat using the special tool. N.B. PLACE IT WITH THE BALLS FACING THE HUB (THIS APPLIES TO BEARINGS WITH PLASTIC CAGE).
  • Page 107 Nexus 500 Engine Refitting the hub cover bearings - Heat the bearing seats on the cover using the heat gun. - Support the hub cover using the column kit. Specific tooling 020151Y Air heater 020476Y Stud bolt set - Insert the intermediate shaft bearing on the cover using the special tool.
  • Page 108 Nexus 500 Engine - Support the hub cover using the column kit. - Insert the wheel shaft oil guard with the sealing lip facing the inside of the cover. - Place the oil guard flush with the crankcase. Specific tooling...
  • Page 109 Nexus 500 Engine Locking torques (N*m) Rear hub cover screws 24 ÷ 27 Flywheel cover - Remove the three bands shown in the figure for an easier removal of the flywheel cover, remove the feed hoses and disconnect the return hose from the pump cover.
  • Page 110 Nexus 500 Engine - Remove the oil filter using a filter tape or shaped cup wrench. - Loosen the 14 fastening screws. - Remove the flywheel cover with the relevant gas- ket and the cooling system sleeve support. N.B. THE SCREWS ARE OF 4 DIFFERENT LENGTHS.

  • Page 111: Removing The Stator

    Nexus 500 Engine - Remove the by-pass and the relevant spring. - Remove the oil pump seal. Removing the stator - Remove the two retaining screws and the cable guide bracket. - Unscrew the 3 fastening screws and remove sta- tor and its wiring.
  • Page 112 Nexus 500 Engine - Remove the blow-by reed valve with the relevant sealing gasket. - Unscrew the fastening screw and remove the gas outlet union with the relevant O-ring. - Remove the water pump impeller by unscrewing it from the relevant shaft.
  • Page 113 Nexus 500 Engine - Remove the sealing ring. - Remove the ceramic ring and the relevant gas- ket. - Remove the sealing ring for the pump shaft lu- brication using a suitably shaped tool. - Remove the engine oil filling cap/dipstick and the check hole cover for the distribution timing.
  • Page 114 Nexus 500 Engine Inspecting the cover components - Install a new oil filter, lubricate the gasket, screw on and finally tighten to the prescribed torque. Locking torques (N*m) Engine oil filter 12 - 16 - Install the supply hose to the cylinder and con- nect the return hose to the pump cover using 3 new clamps.
  • Page 115 Nexus 500 Engine - Check the continuity between the 3 phases. N.B. VALUES ARE STATED AT AMBIENT TEMPER- ATURE. A CHECK WITH THE STATOR AT OP- ERATING TEMPERATURE MAY RESULT IN VALUES HIGHER THAN THOSE STATED. Electric characteristic Resistance: 0.2 - 1 Ω...
  • Page 116 Nexus 500 Engine - Check that the oil filter union and matching sur- face exhibit no deformations or wear. Refitting the stator - Install the stator assembly together with the wir- ing harness, tightening the 3 screws to the pre- scribed torque.
  • Page 117 Nexus 500 Engine - Insert the spring and the by-pass piston on the flywheel cover. N.B. LUBRICATE THE BY-PASS VALVE. Refitting the flywheel cover components - Before reassembling, check that all components are perfectly clean. - For the cover, carefully check all lubrication chan- nels, in particular: - The 3 by-pass channels.
  • Page 118 Nexus 500 Engine - Oil pressure sensor feeding duct. - Oil vapour decantation chamber - Reinstall the blow-by reed valve using a new sealing gasket. - Reinstall the support with head and tighten the screws to the prescribed torque. Locking torques (N*m) Supporting screws with bulkhead 0.3 - 0.4...
  • Page 119 Nexus 500 Engine - Pre-assemble the ceramic seal and the relevant gasket. N.B. PLACE THE CHAMFERING TOWARDS THE GASKET BEING CAREFUL NOT TO FOUL THE CERAMIC RING WITH OIL OR GREASE, WHICH WOULD IMPAIR THE SEAL. - Insert the ceramic seal on the flywheel cover.
  • Page 120 Nexus 500 Engine - Install a new gasket on the engine crankcase. - Check the presence of the three centring dowels. - Turn the crankshaft in order to align the counter- shaft movement sensor with a reference point on the crankcase (see figure).
  • Page 121 Nexus 500 Engine N.B. - THE INTERMEDIATE BOLTS FOR THE RE- MAINING MOUNTING POINTS WITH THE EX- CEPTION OF THE BOLT FOR THE MANIFOLD SUPPORT (SHOWN IN THE FIGURE) ARE SLIGHTLY LONGER. Locking torques (N*m) Flywheel cover screws 11 - 13...
  • Page 122 Nexus 500 Engine The starter is sold as a complete part. Before deciding to replace it, carry out the follow- ing tests: 1 - Battery Check the voltage after not running (a few hours): Voltage >12.5V Check the density of the electrolyte of each cell: Bé...
  • Page 123 Nexus 500 Engine YES go to 6 NO go to 7 NO go to 8 NO go to 9 5 - Restore the connections 6- The values are correct. Finally carry out a check of the power consumption at idle speed.
  • Page 124 Nexus 500 Engine IF THE TRAILING SPEED OF THE CRANKSHAFT IS LOW AND COMBINED WITH STRANGE NOISE, CHECK THE FREEWHEEL OF THE TORQUE LIMITER (SEE THE "FLYWHEEL AND STARTER SYSTEM" CHAPTER). - Remove the three bands shown in the figure for...
  • Page 125 Nexus 500 Engine - Align the holes obtained on the flywheel with the crankcase housing to allow the introduction of the special tool. - Tighten the bushing of the flywheel lock tool on the removing tool threading. - Insert the special tool as shown in the figure,...
  • Page 126 Nexus 500 Engine - Remove the washer. - Insert the nut again so as to slightly uncover the shaft and free the space that was occupied by the washer. CAUTION THIS OPERATION IS REQUIRED AS THE FLY- WHEEL IS STRONGLY LOCKED; THE CONE...
  • Page 127 Nexus 500 Engine - To remove the start-up rim from the freewheel it is necessary to turn it clockwise and pull it out. - Remove the freewheel from the flywheel by loos- ening the 6 fastening screws. SINCE THE FREEWHEEL MUST BE REMOVED,...
  • Page 128 Nexus 500 Engine Inspecting the flywheel components - Check the integrity of the magnets. - Check that the magnet support cage is free from deformation or cracks. - Check that the flywheel splines exhibit no loos- ening. Starter gear rim - Check that there is no wear or abnormal impres- sions on the "rollers"...
  • Page 129 Nexus 500 Engine Intermediate gear - Check that the toothing is not worn. - Check the diameter of the two bearings. Characteristic Gear bearing diameter: 12 - 0 0.011 mm Also check the shaft diameter on the flywheel cov- er and on the engine crankcase.
  • Page 130 Nexus 500 Engine Loctite 243 medium-strength threadlock - Fit the freewheel on the magneto flywheel making sure that the ground side is in contact with the fly- wheel itself, i.e. with wheel Seeger ring visible. - Lock the six clamping screws in criss-cross fash- ion to the prescribed torque.
  • Page 131 Nexus 500 Engine - Lubricate the inside bushing and the starter ring gear hub surface. - Install the start-up rim on the flywheel turning it clockwise and inserting at the same time. Refitting the flywheel magneto - Insert the key on the crankshaft.
  • Page 132 Nexus 500 Engine - Tighten thoroughly the guide bushing of the fly- wheel lock tool and loosen by 1/4 turn. N.B. FAILURE TO OBSERVE THIS RULE CAUSES THE LOCKING OF THE GUIDE ON THE FLY- WHEEL. Specific tooling 020472Y Flywheel lock wrench - Align the 2 holes of the flywheel with the case housing to allow the introduction of the special tool.
  • Page 133 Nexus 500 Engine - Install the chain guide retain plate tightening the 3 screws to the prescribed torque. N.B. BEFORE TIGHTENING THE SCREWS, MOVE THE START-UP RIM IN CONTACT WITH THE CRANKCASE AND CHECK THAT IT IS FREE TO ROTATE IN ANTICLOCKWISE DIRECTION.
  • Page 134 Nexus 500 Engine Removing the intake manifold - Remove the 3 mounting screws. - Remove the intake manifold unit. Removing the rocker-arms cover - Loosen the 6 special screws with stop and the relevant rubber gaskets. - Remove the tappet cover with relevant gasket.
  • Page 135 Nexus 500 Engine - Remove the central screw and the valve lifting device mass stop bell using the special tool. Specific tooling 020565Y Flywheel lock calliper spanner - Remove the return spring and the valve lifting mass with relevant travel end washer.
  • Page 136 Nexus 500 Engine Remove the inside hexagon screw and the coun- terweight as shown in the figure. - Remove the timing belt rim from the camshaft. - Remove the timing belt rim. - Remove the tone wheel. - Remove the engine revolution timing sensor and...

  • Page 137: Removing The Cylinder Head

    Nexus 500 Engine Removing the cam shaft - Unscrew the 3 fastening screws and remove camshaft retaining bracket. N.B. REMOVING THE FASTENING SCREWS MAY BE DIFFICULT. BE CAREFUL NOT TO DAM- AGE THE INSIDE HEXAGON. IF NECESSARY, SEPARATE THE THREADS IN ADVANCE.
  • Page 138 Nexus 500 Engine - Remove the coolant temperature sensor. N.B. THE SENSOR CONTROLS BOTH INJECTION AND THE ANALOGUE INSTRUMENT ON THE PANEL. TO CHECK THIS COMPONENT, SEE THE INJECTION CHAPTER. - Remove the 2 fastening nuts on the head, on the exhaust and on the intake side.

  • Page 139: Removing The Valves

    Nexus 500 Engine Removing the valves - Using the appropriate tool fitted with an adaptor, remove the cotters, caps, springs and valves. Specific tooling 020382Y Valve cotters equipped with part 012 removal tool 020382Y012 bush (valve removing tool) CAUTION ARRANGE THE VALVES SO AS TO RECOGNISE THE ORIGINAL POSITION ON THE HEAD (FLY- WHEEL SIDE AND TRANSMISSION SIDE).
  • Page 140 Nexus 500 Engine Removing the cylinder - piston assy. - Remove the timing chain. - Loosen the fastening screw and remove the spacer and the tightening sliding block. N.B. IT IS ADVISABLE TO MARK THE CHAIN IN OR- DER TO ENSURE THAT THE INITIAL DIREC- TION OF ROTATION IS MAINTAINED.

  • Page 141: Inspecting The Small End

    Nexus 500 Engine Inspecting the small end - Using a bore gauge, measure the connecting rod small end diameter. N.B. IF THE CONNECTING ROD SMALL END DIAM- ETER EXCEEDS THE STANDARD DIAMETER, EXHIBITS WEAR OR OVERHEATING, PRO- CEED TO REPLACE THE CRANKSHAFT AS DESCRIBED IN CHAPTER CRANKCASE AND CRANKSHAFT.

  • Page 142: Inspecting The Piston

    Nexus 500 Engine - Calculate the piston pin coupling clearance. N.B. THE PIN HOUSINGS HAVE 2 LUBRICATION CHANNELS. FOR THIS REASON, MEASURE- MENT MUST BE MADE ACCORDING TO THE PISTON AXIS. Characteristic Standard clearance: 0.001 ÷ 0.010 mm Inspecting the piston - Measure the outside diameter of the piston, per- pendicular to the gudgeon pin axis.
  • Page 143 Nexus 500 Engine - Carefully clean the seal housings. - Measure the coupling clearance between the seal rings and the grooves using suitable sensors, as shown in the diagram. - If the clearance is greater than that indicated in the table, replace the piston.

  • Page 144: Removing The Piston

    Nexus 500 Engine Removing the piston - Install piston and wrist pin onto the connecting rod, aligning the piston arrow the arrow facing to- wards the exhaust. - Insert the locking ring into the special tool, with the opening in the position indicated on the tool.
  • Page 145 Nexus 500 Engine Choosing the gasket - Provisionally fit the piston into the cylinder, without any base gasket. - Install a comparator on the special tool using the short union, as shown in the figure. Specific tooling 020475Y Piston position checking tool - Using an abutment plane, reset the comparator with a preload of a few millimetres.
  • Page 146 Nexus 500 Engine + 0.10 - + 0.185 Gasket thickness 3 0.8 ± 0.05 Refitting the piston rings - Place the scraper ring spring on the piston. - Install the scraper ring keeping the opening op- posed to the spring junction and with the writing "top"...

  • Page 147: Inspecting The Cylinder Head

    Nexus 500 Engine 020468Y Piston fitting ring 020512Y Piston fitting fork Inspecting the cylinder head - Using a trued bar and feeler gauge check that the cylinder head surface is not worn or distorted. Characteristic Maximum allowable run-out: 0.1 mm - In case of irregularities, replace the head.
  • Page 148 Nexus 500 Engine - Remove the centre screw with the washer and the tensioner spring. Check that the one-way mechanism is not worn. - Check the condition of the tensioner spring. - If examples of wear are found, replace the whole assembly.
  • Page 149 Nexus 500 Engine Inspecting the valve housings - Clean the valve seats of any carbon residues. - Using the Prussian blue, check the width of the impression on the valve seat "V". - Measure the inside diameter of each valve guide.
  • Page 150 Nexus 500 Engine - Check the deviation of the valve stem by resting it on a "V" shaped abutment and measuring the extent of the deformation with a comparator. Characteristic Limit values admitted: 0.1 mm - Check the concentricity of the valve head by ar- ranging a comparator at right angle relative to the valve head and rotate it on a "V"...
  • Page 151 Nexus 500 Engine STANDARD VALVE LENGTH Specification Desc./Quantity Inlet: 95.0 ± 0.3 mm Outlet: 94.2 ± 0.3 mm - Check that there are no signs of wear on the surface of contact with the articulated register terminal. - If the checks above give no failures, you can use the same valves.
  • Page 152 Nexus 500 Engine - Measure the unloaded spring length. Characteristic Standard length: 44.4 mm Admissible limit after use: 42.4 mm Refitting the valves - Place the valve spring support washers on the head. - Alternately insert the 4 oil guards using the spe- cial tool.
  • Page 153 Nexus 500 Engine MINIMUM ADMISSIBLE DIAMETER Specification Desc./Quantity Bearing A Ø: 41.910 mm Bearing B diameter: 19.940 mm -Using a gauge, measure the cam height. STANDARD HEIGHT Specification Desc./Quantity Intake 33.988 mm Exhaust: 33.417 mm ADMISSIBLE LIMITS Specification Desc./Quantity Intake 33.740 mm...
  • Page 154 Nexus 500 Engine - If any of the above dimensions are outside the specified limits, or there are signs of excessive wear, replace the defective components with new ones. - Check that the retaining plate seat shown in the figure exhibits no wear.
  • Page 155 Nexus 500 Engine Refitting the head and timing system components - Insert the chain guide sliding block. - Insert the two centring dowels between head and cylinder. - Install the head gasket. N.B. THE FIGURE SHOWS THE INSERTION POSITION OF THE TWO CENTRING DOWELS BETWEEN HEAD AND CYLINDER.
  • Page 156 Nexus 500 Engine - Tighten the fastening nuts on the exhaust and on the intake side to the prescribed torque. Locking torques (N*m) Exhaust / intake head fixing nuts: 10 - 12 - Tighten the 3 side screws to the prescribed tor- que.
  • Page 157 Nexus 500 Engine - Insert pins and rocking levers on the flywheel side. - Lubricate the two rocking levers through the holes at the top. - Clean the camshaft by blowing with little com- pressed air jets, especially the retaining plate housing.
  • Page 158 Nexus 500 Engine - Check that the toothing and the housing of the tone wheel timing peg are free from deformations or dents. - Insert the wheel speed sensor on the camshaft keeping the stroke reference visible. - Install the engine revolution timing sensor using a new O-Ring, orientating it as shown in the figure.
  • Page 159 Nexus 500 Engine - Using the TORX wrench, remove the timing check cap. - Align the wheel speed sensor references with the head as shown in the figure. - Keeping the belt slightly pulled, turn the crank- shaft using the driving pulley to make the reference on the magnet support collimate with that on the flywheel cover.
  • Page 160 Nexus 500 Engine - Install the counterweight mass. - Centre using the bell fastening screw. - Lock the mass fixing screws to the prescribed torque, using the recommended product. Recommended products Loctite 243 Medium-strength threadlock Loctite 243 medium-strength threadlock Locking torques (N*m) Counterweight screw 7 ÷...
  • Page 161 Nexus 500 Engine Loctite 243 Medium-strength threadlock Loctite 243 medium-strength threadlock - Check that the decompression mass is free and that it is pulled by the spring. Locking torques (N*m) Valve lifter mass stop bell fixing screws: 30 - - Place the engine with the valve clearance adjustment timing references aligned with the head.
  • Page 162 Nexus 500 Engine Proceed as follows: - Remove the outside transmission cover as de- scribed in the automatic transmission chapter. - Remove the TDC reference inspection cap be- tween flywheel and crankcase cover. See the fly- wheel cover chapter. - By the driving pulley, turn the engine to find the alignment of the references to identify the TDC.
  • Page 163 Nexus 500 Engine - Replace the inspection cap on the flywheel side. - Connect the diagnostic tester. - Start the engine. - Select the menu on the "parameter" function. - Select the stroboscopic light command in the tra- ditional four-stroke engine position (1 spark 2 revs).
  • Page 164 Nexus 500 Engine - Place the tightener cursor in the rest position, keeping the retain tab pressed. - Install a new tightener on the cylinder using a new gasket. - Tighten the two fastening screws to the prescri- bed torque.
  • Page 165 Nexus 500 Engine - Tighten the two screws indicated in the figure with "1" and "2" to limit the reciprocal sliding of the cover surface with the head surface. - Tighten the remaining 4 screws in a crossed se- quence (3, 4, 5, 6).
  • Page 166 Nexus 500 Engine Crankcase - crankshaft - Remove the outside and inside transmission cov- er and the complete driving pulley as described in "Automatic transmission". - Remove the flywheel cover with the cooling sys- tem sleeves, as described in the "Flywheel cover"...
  • Page 167 Nexus 500 Engine - Before opening the crankcase, check the crank- shaft axial clearance. For this purpose, use a plate (e.g. the special tool) and a support with special tool comparator. Specific tooling 020262Y Crankcase splitting strip 020335Y Magnetic support for dial gauge...
  • Page 168 Nexus 500 Engine - Remove the 14 crankcase coupling screws. N.B. THE FASTENING SCREWS ARE OF 3 DIFFER- ENT LENGTHS. NOTE THEIR CORRECT POSI- TION. - Split the crankcases while keeping the crankshaft inserted on the flywheel side half-crankcase. - Remove the coupling gasket.
  • Page 169 Nexus 500 Engine Removing the oil pump and countershaft con- trol gear. - To remove the control gear, loosen the 4 fasten- ing screws. Remove the gear only if actually required. CAUTION THE SCREWS HAVE A COUNTERSUNK HEAD AND THEIR THREADING IS LOCKED BY LOC- TITE.
  • Page 170 Nexus 500 Engine Replacing the countershaft bearings - Check that the bearings are free from irregular noise or clearance. If it is, replace it. Flywheel-side half-crankcase - Remove the inside seeger ring. - Upturn the half-crankcase. - Remove the bearing from the flywheel side half- crankcase using the special tool and a mallet.
  • Page 171 Nexus 500 Engine - Insert a new bearing on the special tool after greasing the guide seat. - Install the new bearing on the half-crankcase us- ing the special tool. N.B. IF A BEARING WITH PLASTIC CAGE IS USED, KEEP THE BALLS VISIBLE FROM THE CRANKCASE INTERNAL SIDE.
  • Page 172 Nexus 500 Engine 020359Y 42x47-mm adaptor 020439Y 17 mm guide Inspecting the crankshaft components - Check the axial clearance on the connecting rod. Characteristic Standard clearance: 0.20 ÷ 0.40 mm - Check the connecting rod diametrical clearance. Characteristic Standard clearance: 0.046 ÷...
  • Page 173 Nexus 500 Engine Standard thickness: 71.804 - 72.000 mm - Check that shim adjustment is free from scratches. N.B. IN CASE OF NEW UTILISATION, MAINTAIN THE FIRST FITTING POSITION. Specific tooling 020074Y Support base for checking crankshaft alignment - If the crankshaft - crankcase axial clearance is higher than the standard value and the crankshaft exhibits no irregularity, the problem is caused by wear or by a wrong machining on the engine crankcase.
  • Page 174 Nexus 500 Engine - Check that the driving shaft cone, the tab seat, the oil seal capacity, the toothed gear and the threaded tangs are in good working order. - In case of failures, replace the crankshaft. N.B. MAIN BEARINGS CANNOT BE MODIFIED.
  • Page 175 Nexus 500 Engine N.B. THE JET IS FED THROUGH THE MAIN BUSH- INGS. PROPER OPERATION OF THIS COMPO- NENT IMPROVES PISTON CROWN COOLING. CLOGGING HAS EFFECTS THAT ARE DIFFI- CULT TO DETECT (PISTON TEMPERATURE INCREASE). FAILURE OR LEAKS CAN CAUSE...
  • Page 176 Nexus 500 Engine Inspecting the crankshaft plain bearings - To obtain a good bushing lubrication it is neces- sary to have both an optimal lubricating pressure (4 bar) and a good oil flow rate; the bushings must be correctly positioned so as not to obstruct the oil supply channels.
  • Page 177 Nexus 500 Engine Coupling chart COUPLING THE SEMI-SHAFTS WITH THE SEMI-CHASSIS AND BUSHES Name Description Dimensions Initials Quantity Half-shaft category Spare crankcase 1 - Bushing catego- set-up FC1 - Dis. ry B CM1033015001 Half-shaft category Spare crankcase 2 - Bushing catego- set-up FC1 - Dis.
  • Page 178 Nexus 500 Engine - Before installing the gear on the crankshaft, care- fully clean the two matching surfaces removing any residues of LOCTITE from the holes using a brush. Blow with compressed air and degrease the mounting holes on both surfaces to make the new LOCTITE grip.
  • Page 179 Nexus 500 Engine - Insert the crankshaft on the pin and into the bush- ing. - Before inserting thoroughly, make the oil pump gear align with the control gear. - Insert thoroughly and remove the special tool. N.B. WHEN INSERTING THE SHAFT ON THE HALF-CRANKCASE, BE CAREFUL NOT TO DAMAGE THE MAIN BEARING WITH THE THREADED TANG OF THE CRANKSHAFT AND WITH THE TIM- ING CONTROL TOOTHED PINION.
  • Page 180 Nexus 500 Engine 020376Y Adaptor handle - Insert the gasket on the flywheel side half-crank- case. - Lubricate the main bearing on the transmission side half-crankcase. - Couple the 2 half-crankcases being careful not to damage the bushing on the transmis- sion side half-crankcase with the threaded tang of the crankshaft.
  • Page 181 Nexus 500 Engine - Install the flywheel with start-up control as de- scribed in the "Flywheel and start-up" chapter. - Install the flywheel cover with the cooling system sleeves, as described in the "Flywheel cover chap- ter". - Install the complete driving pulley, the transmis-...
  • Page 182 Nexus 500 Engine OIL PUMP Specification Desc./Quantity Type Trochoidal Rotor thickness 8 mm Assembly clearances Lobe ends 0.05-0.008 mm Outside rotor radial clearance 0.05- 0.12 mm Rotor axial clearance 0.025 - 0.065 mm BY-PASS Specification Desc./Quantity Type with piston Plunger diameter 13.9 - 0.039 -0.057 mm...
  • Page 183 Nexus 500 Engine Conceptual diagrams PRINCIPLE DIAGRAM Specification Desc./Quantity Camshaft Cylinder-head plane Cylinder-crankcase plane Water pump impeller Minimum oil pressure sensor Oil filter cartridge To the oil sump By-pass valve Oil pump Mesh pre-filter Crankshaft Connecting rod General characteristics Lubrication circuit is split into two sections:...
  • Page 184 Nexus 500 Engine The pump is controlled by means of a piston by-pass calibrated to 4 bar. This is located before the cartridge filter and both are installed on the flywheel cover, so that the seal of the filter is subject to the pressure of the circuit.
  • Page 185 Nexus 500 Engine YES - go to 3 NO go to 11 3 Check the actual oil pressure. AHEAD - go to 4 4 - Remove the switch and fit the special tool with the relevant gasket. Specific tooling 020193Y Oil pressure gauge...

  • Page 186: Oil Pressure Check

    Nexus 500 Engine approx. 1.5 bar YES go to 7 NO go to 8 7 - Replace the oil minimum pressure switch. 8 - If pressure lower than 1.3 - 1.5 bar is measured. AHEAD go to 9 9 - Replace the oil filter and repeat the pressure check with oil at 80°C.

  • Page 187: Oil Pump

    Nexus 500 Engine 2 - Install the special tool. Specific tooling 020193Y Oil pressure gauge 020434Y Oil pressure control fitting AHEAD go to 3 3 - Check the system pressure with cold engine and medium - high speed. Standard pressure < 6 bar YES go to 4 NO go to 5 4 - Replace the damaged components.
  • Page 188 Nexus 500 Engine - Remove the oil pump complete with the gearing by loosening the 2 retaining screws through the eyes machined in the gearing proper. - Remove the gasket. - Remove the two screws and the oil pump cover.
  • Page 189 Nexus 500 Engine - Remove and wash the rotors thoroughly with pet- rol and compressed air. - Extract the shaft with its gear and check that it is in good working order and free from wear. - Reassemble the rotors in the pump body, keep-...
  • Page 190 Nexus 500 Engine - Check the rotor axial clearance using a rectified bar as reference plane, as shown in the figure. Characteristic Limit values admitted: 0.1 mm Inspection - For tests on the oil pump, see the "Lubrication" chapter. Refitting - Make sure the gasket is in the correct position.
  • Page 191 Nexus 500 Engine Failure to observe the tightening torque may alter the coupling clearance of the rotors with the pump body. Locking torques (N*m) Screws fixing oil pump to the crankcase 5 - 6 - Insert the countershaft with gearing into the fly- wheel-side half-crankcase.
  • Page 192 Nexus 500 Engine Oil pump cover screws 0.7 ÷ 0.9 ENG - 110...
  • Page 193 INDEX OF TOPICS INJEC NJECTION...
  • Page 194 Nexus 500 Injection TERMINALS CONDITIONS STANDARD 5 - 23 Switch in position "ON" Battery voltage Switch on "RUN" Side stand raised Electric fan off CIRCUIT LAYOUT Specification Desc./Quantity electronic control unit Electric fan Fuse Key switch Electric fan remote control switch...
  • Page 195 Nexus 500 Injection - Coolant level in the expansion tank - bleeding of the inlet hose to the engine - Bleeding of the outlet from the head - Function of the thermostat - Function of the pump For these checks, see chapter "Cooling system".
  • Page 196 Nexus 500 Injection 9 - Replace the remote control switch YES go to 8 10 - Connect the special tool between the control unit and the system. Do not connect the electronic control unit YES go to 11 11 - Check for positive battery voltage at pin 85 of the remote control switch connector.
  • Page 197 Nexus 500 Injection If the fault continues, replace the electronic control unit. Make sure the entire exhaust system is sealed. Remove the intake cap on the exhaust pipe, connect the dissipater and the extension pipe. Warm-up the engine and use an exhaust analyser to check the carburation of the idle speed, if neces- sary, restore the correct setting using a scooter Tester, see «Adjusting idle carburation».
  • Page 198 Nexus 500 Injection - spark plug - that air filter is clean - that throttle body is clean - intake system for sealing - exhaust system for sealing - valve clearance - fuel filter - Fuel pressure N.B. IDLE SPEED IS OBTAINED BY PRECALIBRATING THE THROTTLE BODY AND ACTIVATING THE STEPPER.
  • Page 199 Nexus 500 Injection YES go to 8 8 - Activate the exhaust fumes analyser and check the following conditions are present: - CO = 1.25±0.25% - CO2 = 14.50±1% YES go to 9 NO go to 10 9 - The adjustment is correct.
  • Page 200 Nexus 500 Injection 14 - After having modifying a trimmer value, wait until the CO value becomes steady. In case of incorrect adjustment, press OK to store the value in the control unit memory. YES go to 15 15 - Select «PARAMETERS» and «ECU DATA»...
  • Page 201 Nexus 500 Injection In any case, check the CO value again. EMS injection system The injection system is of the integrated injection and ignition type. Injection is indirect in the manifold through electronic injector. Injection and ignition are timed on the 4-stroke cycle using a tonne wheel pivoted on the camshaft control and a reluctance variation sensor.
  • Page 202 Nexus 500 Injection Of course, this cannot happen when the rev counter signal is missing, or when the failure concerns the control circuits: - Fuel pump - H.V. coil - Injector The control unit is provided with a self-diagnosis system connected to an indicator light in the in- strument panel.
  • Page 203 Nexus 500 Injection The EMS control unit power supply is further con- trolled by the emergency switch and by the side stand switch, to allow further safety of the scooter. Precautions 1. Before fixing any part of the injection system, check to see if there are any registered faults. Do not disconnect the battery before checking for faults.
  • Page 204 Nexus 500 Injection 14. Before reconnecting the quick couplers of the power supply system, check that the terminals are perfectly clean. Terminals setup Layout of the system-side connectors and the connectors on the electronic control unit. ELECTRONIC CONTROL UNIT SIDE...
  • Page 205 Nexus 500 Injection Specification Desc./Quantity Stepper motor Stepper motor Sensor power supply Control unit negative Stepper motor Stepper motor Continuous power supply (positive) IMMOBILIZER DECODER Specification Desc./Quantity Immobilizer LED control (negative) Base power supply (positive) Negative Electronic control unit EMS...
  • Page 206 Nexus 500 Injection EMS circuit diagram Specification Desc./Quantity Electric fan remote control switch Electric fan Control unit remote control switch HV coil Fuel pump Instrument panel Injector Fluid temperature sensor Air temperature sensor Throttle potentiometer Stepper motor Stepper motor Electronic control unit EMS...
  • Page 207 Nexus 500 Injection Specification Desc./Quantity Fuse Utilities Troubleshooting procedure This section makes it possible to find the solutions to use in troubleshooting. Engine does not start ENGINE DOES NOT START IF ONLY PULLED Possible Cause Operation Immobiliser enabling signal System not encoded...
  • Page 208 Nexus 500 Injection Possible Cause Operation Injector capacity (low) Injector sealing (poor) Correctness of the parameters Coolant temperature Stepper throttle valve position intake air tempera- ture (steps and actual opening) Cleaning of the auxiliary air pipe and throttle valve; air filter efficiency...
  • Page 209 Nexus 500 Injection Possible Cause Operation Correctness of the parameters Throttle valve position sensor Stepper Coolant temperature sensor Intake air temperature sensor Intake system sealing (infiltrations) Intake manifold - head Throttle body - manifold Intake sleeve Filter box Fuel feed (low pressure)
  • Page 210 Nexus 500 Injection Possible Cause Operation Injector revolution timing sensor Air temperature Coolant temperature. Atmospheric pressure Intake system cleaning Air filter Diffuser and throttle valve Additional air pipe and Stepper Intake system seal Intake sleeve Filter box Ignition system Spark plug wear check...
  • Page 211 Nexus 500 Injection Engine knocking PRESENCE OF KNOCKING (OVERHEAD KNOCKING) Possible Cause Operation Presence of faults detected by the self diagnosis Pump relay H.V. coil Injector revolution timing sensor Air temperature Coolant temperature. Atmospheric pressure Ignition efficiency Spark plug Parameter reliability...
  • Page 212 Nexus 500 Injection 1 - Check whether the immobiliser system LED in- dicates that the switch is in position "ON" and that the deterrent flashing is on. YES go to 2 NO go to 7 2 - The decoder is properly programmed.
  • Page 213 Nexus 500 Injection Terminal no. 4= battery negative YES go to 11 NO go to 13 Specific tooling 020481Y Control unit interface wiring 11 - Decoder with proper base power supply. Use the special tool to check the control unit power...
  • Page 214 Nexus 500 Injection 3 - Continuous power supplies are regular 4 - Check the working order of the fuse no. 4 and 5 located in the fuse holder on the right side. YES go to 5 NO go to 6 5 - Place the special tool between control unit and injection system.
  • Page 215 Nexus 500 Injection 9 - Control unit with proper continuous power sup- ply. 10 - If only one component is not powered check the relevant connector. If the problem involves both the decoder and CPU check the continuity of the decoder CPU power supply line.
  • Page 216 Nexus 500 Injection Diagnostic circuit * CONNECTOR FOR DIAGNOSTIC TESTER A = INJECTION CONTROL UNIT Connect the diagnostic tester. Specific tooling 020460Y Scooter diagnosis and tester If the diagnostic tester displays "No reply from the control unit", disconnect the continuous power supply for 10 seconds and switch to "ON"...
  • Page 217 Nexus 500 Injection 5 - Check the following conditions: PIN 1 diagnostic socket - PIN 10 control unit = continuity PIN 2 diagnostic socket - PIN 23 control unit = continuity with earth PIN 3 diagnostic socket - PIN 9 control unit = con- tinuity 10 - 23 = insulation (>1 MΩ)
  • Page 218 Nexus 500 Injection Specification Desc./Quantity - Switch set to "ON" - Side stand raised - Switch to "RUN" STANDARD VALUES : O V TERMINAL: 15 - 23 CONDITIONS: AFTER THE CHECK - Switch set to "ON" - Side stand raised - Switch to "RUN"...
  • Page 219 Nexus 500 Injection 5 - Check the control unit connector. Check the control unit. 6 - Check the continuity between pin 15 of the CPU and the brown-black wire of the 6 input connector of the instrument unit. The injection CPU manages the negative of the light. The light must go off after the initial check. The light goes on again when the CPU autodiagnosis detects a fault.
  • Page 220 Nexus 500 Injection The tester pages display the list of errors detecta- ble by the auto-diagnosis. Errors detected by the auto-diagnosis are marked by one or two reference dots. They are arranged on two lines: Line A = current failures (present)
  • Page 221 Nexus 500 Injection Fuel supply system Fuel is fed to the injector by a pump, a filter and a pressure regulator integrated with the fuel level in- dicator inside the tank. The pump unit is connected to the injector by:...
  • Page 222 Nexus 500 Injection Circuit diagram CIRCUIT LAYOUT Specification Desc./Quantity Fuse Fuse 10 A Switch Engine stop remote control switch Fuse Control unit remote control switch HV coil Fuel pump Injector Electronic injection control unit Main remote control switch Engine stop switch...
  • Page 223 Nexus 500 Injection - To remove the injector, remove the central set screw of the "T" shunt acting as a support for the injector. - Remove the injector from the manifold. - Once the engine is repaired check the CO% value again while idling to make sure it is within the prescribed limits.
  • Page 224 Nexus 500 Injection THE THROTTLE BODY IS A PART WHICH INCLUDES VARIOUS COMPONENTS AND IS USUAL- LY SUPPLIED COMPLETE. TO TEST THESE COMPONENTS SEE THE "INJECTION" CHAPTER. - Remove the 3 retaining screws indicated in the figure. CAUTION THE THROTTLE BODY COMES PRE-CALIBRATED. TAMPERING WITH THE THROTTLE STOP REGISTER IS TO BE ABSOLUTELY AVOIDED.
  • Page 225 Nexus 500 Injection side, can be easily removed. Once clean, the throttle body guarantees an air flow exactly the same as the original. Throttle valve fouling is phenomenon that happens at different times depending on how the scooter is used, weather conditions and idle speed adjustment. This phenomenon can be easily detected as a gradual poor idle signals it.
  • Page 226 Nexus 500 Injection Circuit check Proceed as follows: 1 - Set the switch to "ON" with emergency switch to "RUN" and side stand raised. The pump rotates for 2 seconds. YES go to 2 NO go to 3 2 - Try to start up. Check that the engine speed matches the pump rotation.
  • Page 227 Nexus 500 Injection 12 - Check and restore the earth insulation of the control unit line 19 and of the pump remote control switch line 85. YES go to 14 13 - Install the special tool between control unit and the injection system.
  • Page 228 Nexus 500 Injection 19 - Disconnect the following connectors: fuel pump, H.V. coil, injector YES go to 22 20 - Check the efficiency of the pump remote con- trol switch. Check the wiring continuity between remote control switch and pump.
  • Page 229 Nexus 500 Injection - Relay closure - Pump rotation - Relay opening YES go to 31 NO go to 32 31 - The pump is fed. Perform a functional check of the pump. 32 - Check the efficiency of the pump connector.
  • Page 230 Nexus 500 Injection The special tool is equipped with fast-release fit- tings, similar to those provided for the circuit. In order to disconnect the female terminals (injec- tor side), it is necessary to press the two exten- sions and draw them.
  • Page 231 Nexus 500 Injection Select the menu on the "ACTIVE DIAGNOSIS" function. Select the "PUMP DIAGNOSIS" function. YES go to 2 2 - Enable the function with continuous power sup- ply on and engine off. The control unit starts the pump for 30 seconds YES go to 3 3 - Let the system bleed for a few seconds.
  • Page 232 Nexus 500 Injection 1 - Select the diagnostic tester menu on the «AC- TIVE DIAGNOSIS» function. Select the «PUMP DIAGNOSIS» function. The pump starts for 30 seconds. YES go to 2 2 - Let bleed for a few seconds. Make sure that there are no leaks.
  • Page 233 Nexus 500 Injection AHEAD go to 7 7 - Check whether the pressure decreases with the same trend as the system when free from bottle- necks AHEAD go to 8 8 - Pressure decreases much more slowly YES go to 9 NO go to 10 9 - Replace the pressure regulator.
  • Page 234 Nexus 500 Injection 16 - Disconnect the pump connector, start the en- gine, wait until it stops and connect the connector again. Disconnect the fuel return pipe from the pump sup- port (left pipe). AHEAD go to 17 17 - Introduce the return pipe into a graduated container.
  • Page 235 Nexus 500 Injection With infinite resistance, the pump does not rotate. With resistance close to 0 Ω, the pump power consumption is too high, with the possibility of blowing the 10 A fuse No. 2. Perform the following check. Pump consumption check...
  • Page 236 Nexus 500 Injection N.B. DO NOT BLOW THE FILTER WITH COMPRESSED AIR. A DAMAGED FILTER MAY CAUSE THE INJECTOR CLOGGING. Pump bracket overhaul To remove the pump support from the tank, pro- ceed as follows: - Disconnect the electric connector.
  • Page 237 Nexus 500 Injection To replace the components, proceed as follows: (1) Level indicators: - Note the assembly position and the path of the two connecting wires. Pos 2 = wire connected to the circuit Pos 3 = wire connected to the mobile arm Pass the wires through the hole obtained between filter and pressure regulator.
  • Page 238 Nexus 500 Injection TO OVERCOME THE RESISTANCE OF THE O-RINGS, LEVER WITH A SCREWDRIVER THROUGH THE OPENINGS OBTAINED ON THE STOP INSERTION SIDE. - Lubricate the O-rings and repeat the operations in the reverse order for re-assembly. (3) Fuel pump...
  • Page 239 Nexus 500 Injection - Remove the pump mounting washer - Remove the filter coupling pipe - Remove the pump with annular support and pre- filter. - If the pump requires replacement, remove the pre-filter and the annular support. - For re-assembly, perform the removal operations in the reverse order using a new band for the de- livery pipe and a new pump mounting washer.
  • Page 240 Nexus 500 Injection (4) Fuel filter The fuel filter is supplied already assembled with the pump support. To replace the support, move the level indicator, the pressure regulator and the pump from the old to the new support. For these operations, follows the instructions giv- en above.
  • Page 241 Nexus 500 Injection Inspecting the injector circuit Electric characteristic TERMINAL: 13 - 23 CONDITIONS: During the pump timing with engine off STANDARD: Battery voltage CIRCUIT LAYOUT Specification Desc./Quantity Electronic control unit Injector HV coil Pump Control unit remote control switch...
  • Page 242 Nexus 500 Injection 2 - Enable the function with continuous power sup- ply on and engine off. The control unit controls the fuel pump continuously and at the same time starts the injector opening. The injector openings are re- peated for a few seconds.
  • Page 243 Nexus 500 Injection 12 - Check the power supply circuit with the 10A fuse and the remote control switch. Common feeding to the fuel pump. 13 - Check the pump relay control circuit 14 - Install the special tool between the injection system and the control unit.
  • Page 244 Nexus 500 Injection NO go to 20 20 - Repair or replace the cable harness. 21 - Check the continuity between the injector power supply connector (red - yellow) and pin 13. Restore the continuity, if required, or replace the wiring 22 - Replace the injector.

  • Page 245: Troubleshooting

    Nexus 500 Injection Collect the fuel delivered by the injector into the graduated container. Power supply pressure = 300 KPa (3 BAR) Quantity delivered = approx. 40 cm3 YES go to 3 NO go to 4 3 - Perform the injector sealing test.
  • Page 246 Nexus 500 Injection SUGGESTION FOR TROUBLESHOOTING Specification Desc./Quantity 1. Power supply - Battery voltage - Burnt fuse - Remote control switches - Connectors 2. Chassis earth 3. Fuel supply - Faulty fuel pump - Dirty fuel filter 4. Ignition system...

  • Page 247: System Components

    Nexus 500 Injection System components The system consists of: -EMS system control unit - Decoder - Aerial - Master key (red) - Service key (black) - Deterrent and diagnosis LED Specification Desc./Quantity Main fuse 30 A Fuse 7.5 A Fuse...
  • Page 248 Nexus 500 Injection Virgin circuit When control unit (ECU) and decoder are not pro- grammed, the following conditions occur: - Key switch set to "OFF". Deterrent flashing inac- tive. - Key switch set to "ON". Ignition and injection dis- abled and LED on with solid light.
  • Page 249 Nexus 500 Injection Set the switch to "ON" and select the diagnostic tester menu to the immobiliser function. Scroll the pages to display the control unit data. N.B. AN UNPROGRAMMED SYSTEM CANNOT BE DETECTED UPON FIRST FITTING, OR IN CASE THE DECODER AND THE CONTROL UNIT ARE REPLACED CONCURRENTLY.
  • Page 250 Nexus 500 Injection LED signals When the key switch is set to "ON" and program- ming is performed normally, the LED switches on as shown in the figure. WITH MASTER KEY After the confirmation flash when switching to "ON", a number of flashes are emitted, equal to the number of keys used for programming.
  • Page 251 Nexus 500 Injection Checking master-box data Connect the diagnostic tester. Set to "ON" and select the immobilizer function. Scroll the pages the find the data. Specific tooling 020460Y Scooter diagnosis and tester The information will be as follows: - Blank control unit "OFF"...
  • Page 252 Nexus 500 Injection 1st step: A flash: "ON" switching recognition 2nd step: Series of flashes: diagnosis code indication 3rd step: Steady light on or off: on = start-up disabled off = start-up enabled Code 1 Code 1 indicates a non-programmed system.
  • Page 253 Nexus 500 Injection Code 2 Code no. 2 denotes a system where the decoder does not perceive the transponder signal. - Start-up disabled - Injection telltale light on, steady In this case, proceed as follows: 1 - Check whether the code is repeated using the second key.
  • Page 254 Nexus 500 Injection Code 3 Code no. 3 denotes a system where the decoder perceives a transponder not provided for by pro- gramming. - Start-up disabled - Injection telltale light on, steady 1- Check whether the code is still displayed using the master key...
  • Page 255 Nexus 500 Injection 3 - Check for any short circuits on the instrument unit power supply line, check that the instrument unit has not short-circuited YES go to 5 4 - Check whether the LED comes on when pin No.
  • Page 256 Nexus 500 Injection CIRCUIT LAYOUT Specification Desc./Quantity electronic control unit Engine rpm sensor The sensor allows the rotations and the angular position of the crankshaft to be recognised by reference to the TDC. Since the wheel speed sensor is pivoted on the camshaft it is also possible to recognise the 4-stroke cycle.
  • Page 257 Nexus 500 Injection Any faults discovered in this phase are signalled via the injection light. The fault continues to be signalled, but the circuit is only checked when turning to "ON". Therefore faults which occur or disappear after turning to "ON" are not acknowledged.
  • Page 258 Nexus 500 Injection THE FAULT HAS BEEN RECORDED IN CUR- RENT STATUS: The control circuit gave a negative result when switching to "ON". AHEAD go to 8 3 Select the "PARAMETERS" function on the menu. Check the number of «lost synchronisations»: 1 TOOTH and >...
  • Page 259 Nexus 500 Injection RESISTANCE OF THE REVOLUTION TIMING SENSOR: ( 25°C) Specification Desc./Quantity 860 Ω ± 130 Ω Model with 1 clamp: 680 Ω ± 100 Ω Model with 2 clamps: YES go to 11 NO go to 12 11 - Check the earth isolation between a pole and the shielding.
  • Page 260 Nexus 500 Injection YES go to 15 NO go to 16 15 - Check the connectors carefully. Disconnect and check the continuity between connector and pin 7-12 Electric characteristic Connector - 7 = Continuity Connector - 12 = Continuity Fix the connectors or replace the cable harness.

  • Page 261: Circuit Diagram

    Nexus 500 Injection -A POOR CABLE SHIELDING CAN IMPAIR THE ENGINE PERFORMANCE AT HIGH SPEED. HT coil This section describes the ignition system operation. Circuit diagram Electric characteristic TERMINALS: 20 - 23 CONDITIONS : During the pump timing with engine off.
  • Page 262 Nexus 500 Injection The coil magnetisation time is controlled by the control unit. The ignition power is increased during the engine start-up. The injection system recognises the 4-stroke cycle and therefore, ignition is only controlled during compression. To check the ignition circuit, proceed as follows: 1 - Connect the diagnostic tester.
  • Page 263 Nexus 500 Injection If you want to increase the test time, enable the "pump relay diagnosis" function (30 seconds) YES go to 7 NO go to 8 7 - The coil primary control circuit is efficient. Carefully check the connectors to the control unit and to the coil.
  • Page 264 Nexus 500 Injection YES go to 12 NO go to 11 11 - Check the continuity of the pink-black wire in the two systems. Electric characteristic Pink-black (coil connector)-20 = Continuity YES go to 12 NO go to 13 12 - Check the earth insulation of the negative line.
  • Page 265 Nexus 500 Injection Electric characteristic Primary resistance = 0.5 ± 8% YES go to 16 NO go to 19 16 - Check the earth insulation of the primary circuit Measure between one of the primary terminals and earth. Electric characteristic Primary-earth = Ω...
  • Page 266 Nexus 500 Injection YES go to 18 NO go to 19 18 - The coil is conforming. 19 - Replace the coil Inspecting the spark plug shielded cap Measure the shielded cap resistance. Electric characteristic Resistance: 5 KΩ If different values are measured (<1; >20KΩ), re- place the shielded cap.
  • Page 267 Nexus 500 Injection Proceed as follows: - Remove the transmission compartment cover as described in the "automatic transmission" chapter. - Remove the TDC reference inspection cap be- tween flywheel and crankcase cover. See the "fly- wheel cover" chapter - By the driving pulley, turn the engine to find the alignment of the references to identify the TDC.
  • Page 268 Nexus 500 Injection - Replace the inspection cap on the flywheel side. - Connect the diagnostic tester. - Start the engine. - Select the menu on the "parameter" function. - Select the stroboscopic light command in the tra- ditional four-stroke engine position (1 spark 2 revs).
  • Page 269 Nexus 500 Injection CIRCUIT LAYOUT Specification Desc./Quantity electronic control unit Valve position sensor Air temperature sensor Fluid temperature sensor The coolant temperature sensor is installed on the engine head and provides the indications for the digital instrument and for the injection.
  • Page 270 Nexus 500 Injection YES go to 6 NO go to 7 6 - The temperature sensor is providing probably correct information. Check at approx. 80° C. 7 - Install the special tool. WARNING DO NOT CONNECT THE CONTROL UNIT CONNECTOR.
  • Page 271 Nexus 500 Injection Electric characteristic Blue-white-4 = 0W (continuity) Light blue/green-22 = 0 ohm. (Continuity) YES point 12 12 - Repair or replace the cable harness. YES go to 10 13 - Check that the sensor circuit is earth insulated.
  • Page 272 Nexus 500 Injection Specific tooling 020481Y Control unit interface wiring 16 - Measure voltage at terminals 4 and 22; TEMPERATURE VOLTAGE Specification Desc./Quantity -10° C +10° C +20° C +30° C +80° C YES go to 21 NO go to 17...
  • Page 273 Nexus 500 Injection 21 - Start the engine and check that voltage de- creases gradually according to the temperature increase as per table. YES go to 22 NO go to 23 22 - The temperature signal is conforming. 23 - Replace the temperature sensor.
  • Page 274 Nexus 500 Injection CIRCUIT LAYOUT Specification Desc./Quantity electronic control unit Valve position sensor Air temperature sensor Fluid temperature sensor The sucked air temperature sensor is installed in the bottom side of the throttle body on the filter box side. The sensor is an NTC and has the same functional layout as the coolant temperature sensor.
  • Page 275 Nexus 500 Injection ambient temperature indicated by the digital instrument. The three indications are equal or they are slightly different (e.g. 1° C). YES go to 6 NO go to 7 6 - The sucked air temperature sensor is providing an incorrect information.
  • Page 276 Nexus 500 Injection YES go to 13 NO go to 11 11 - If slightly higher values are detected, check the connectors. If infinite resistance is detected (>1Mohm) check the continuity between the two lines with disconnected connectors. Electric characteristic...
  • Page 277 Nexus 500 Injection YES go to 15 NO go to 14 14 - Repair or replace the wiring. Check the valve position and the fluid temp. lines. YES go to 13 15 - Connect the special tool to the control unit.
  • Page 278 Nexus 500 Injection Repeat the wiring and sensor continuity checks. YES go to 18 Electric characteristic Measured value = Repeat the sensor circuit earth insulation check. YES go to 19 NO go to 20 19 - Check the control unit connector. Check the control unit power supply. Replace the control unit, if necessary.
  • Page 279 Nexus 500 Injection YES go to 4 NO go to 5 4 - The ambient pressure signal is correct. 5 - Replace the injection control unit. Throttle valve opening sensor Throttle position sensor (t.p.s.) Electric characteristic TERMINALS: 1 - 22 CONDITIONS: Switch set to "ON"...
  • Page 280 Nexus 500 Injection CIRCUIT LAYOUT Specification Desc./Quantity electronic control unit Valve position sensor Air temperature sensor Fluid temperature sensor The throttle valve position sensor is not removable and is installed on the throttle body. This sensor receives a 5-V power supply from the...
  • Page 281 Nexus 500 Injection 2 - Select the diagnostic tester menu on the "PA- RAMETERS" function. Check whether the control unit recognises the ex- treme positions: Throttle valve to minimum Throttle valve to maximum YES go to 4 NO go to 3 3 - Check the adjustment of the throttle valve control flexible transmissions.
  • Page 282 Nexus 500 Injection 8 - Check the earth insulation of the three circuit lines. Electric characteristic 22-23 = Ω infinite (>1M) 1-23 = Ω infinite (>1M) 11-23 = Ω infinite (>1M) YES go to 10 NO go to 9 9 - Repair or replace the injection wiring YES go to 8 10 - Connect the special tool to the control unit.
  • Page 283 Nexus 500 Injection 12 - Connect the throttle valve position sensor connector. Repeat the voltage measurement between terminals 1 and 22 of the special tool. Electric characteristic 1-22 = 5±0.2 V YES go to 13 NO go to 14 13 - Measure voltage between terminals 11 and 22. Gradually open the throttle valve and check that the voltage value increases progressively.
  • Page 284 Nexus 500 Injection Pre-calibration entails regulating the minimum opening of the throttle valve to obtain a certain flow of air under preset reference conditions. Pre-calibration ensures optimal air flow for the control of the idling. This regulation must not be tampered with in any way whatsoever.
  • Page 285 Nexus 500 Injection Guaranteeing that this position will be kept, send a confirmation for the TPS reset procedure. Select the "PARAMETERS" function and check that the TPS reset "YES" is displayed. Reset should be performed in the following cases: - on first fitting.
  • Page 286 Nexus 500 Injection Step motor CIRCUIT LAYOUT Specification Desc./Quantity electronic control unit Stepper motor Stepper motor The throttle body is provided with an auxiliary air circuit. This is enabled by a piston valve controlled by a stepper motor. The stepper is powered by the control unit only when the opening must be changed.
  • Page 287 Nexus 500 Injection To recover possible adjustments, every switching to "OFF" causes the piston to close up to end of travel and to open up again by a fixed number of steps (self-reset). When the control unit changes the stepper open- ing "steps"...
  • Page 288 Nexus 500 Injection YES go to 3 NO go to 4 3 - Start the engine and let it warm up. With a coolant temperature of more than 70°C, the control unit must control the stepper with about 45 "steps".
  • Page 289 Nexus 500 Injection Resistance = approx. 51 Ω YES go to 11 NO go to 10 9 - Test successful. No variations of revolutions. Remove the throttle body. Check the auxiliary air circuit cleaning. Switch from "ON" to "OFF" and again to "ON" and check wheth- er the piston valve moves.
  • Page 290 Nexus 500 Injection YES go to 12 NO go to 13 12 - Check the earth insulation of the 4 stepper lines. Electric characteristic 14-23 = >1 MΩ (infinite) 6-23 = >1 MΩ (infinite) 21-23 = >1 MΩ (infinite) 24-23 = >1 MΩ...
  • Page 291 Nexus 500 Injection YES go to 16 NO go to 15 15 - Check cable harness and connectors more carefully. 16 - Connect the control unit connector. Set the switch to «ON» with switch to «RUN» and side stand raised. Repeat the "ON" "OFF" "ON"...
  • Page 292 Nexus 500 Injection INJEC - 100...
  • Page 293 INDEX OF TOPICS SUSP USPENSIONS...

  • Page 294: Removing The Front Wheel

    Nexus 500 Suspensions This section is devoted to operations that can be carried out on the suspension. Front Removing the front wheel - Loosen the two wheel axle fastening screws shown in the figure - Remove the wheel axle locking nut.
  • Page 295 Nexus 500 Suspensions - Support the front wheel with two wooden shims to prevent scratches in case of contact with the rim. - Insert the punch consisting of the adapter handle, adapter and 15 mm guide on the odometer motion drive side to allow removing the LH bearing and the spacer bushing.

  • Page 296: Front Fork

    Nexus 500 Suspensions - Upturn the wheel and insert the inside spacer with the portion provided with snap ring facing the LH bearing installed before. - Heat the bearing seat on the odometer motion drive side using the thermal gun.
  • Page 297 Nexus 500 Suspensions Removal - Remove the front wheel. - Remove the front mudguard - Remove the front brake calliper - Remove the front and rear handlebar cover. - Remove the pin mounting the handlebar to the steering tube. - Remove the handlebar and rest it on the shield back plate.
  • Page 298 Nexus 500 Suspensions Check pump unit - Check that the oil holes on the pumping are free from clogging. - Check that the sealing snap ring is not damaged. Servicing tapered bearing seats - Check that the seats and the tapered bearings exhibit no scratches or wear.
  • Page 299 Nexus 500 Suspensions - Loosen the stem support clamp and remove fork leg and stem. - Remove the spring. - Drain the oil. - Remove the screw with copper washer shown in the figure. To prevent the pumping member rota- tion, insert an inside 22 mm hexagon spanner into the stem.
  • Page 300 Nexus 500 Suspensions - Extract the oil guard "D", the abutment washer "C" and the top bushing "B". - Widen and remove the bottom bushing "A". Refitting Installing stems on fork legs Preassemble the stem as indicated: - Install the bushing from the bottom of the stem - Insert the following from the top of the stem: 1 Bushing "B"...
  • Page 301 Nexus 500 Suspensions TUBE SIZE Specification Desc./Quantity Inside: 44 mm Outside: 51 mm Height: approx. 105 mm - Insert the contrast spring into the pumping mem- ber. - Insert the pumping member into the stem. - Insert the stem into the fork leg being careful not to let the guiding bushing come out of the stem.
  • Page 302 Nexus 500 Suspensions - Insert the spring with the thickest turns at the bottom. - Insert the stem into the fork clamp. - Tighten the clamp to screw the top stem closing cap. - Check that the sealing ring on the cap is in good working order, then tighten the cap on the stem to the prescribed torque.
  • Page 303 Nexus 500 Suspensions Locking torques (N*m) Holding torque of lower ring nut 20 ÷ 25 - Tighten to the prescribed torque. Locking torques (N*m) Lower steering ring nut 10 - 13 ** - Install the space washer. - Using the special tool, tighten the second locking ring nut on the steering tube to the prescribed torque.
  • Page 304 Nexus 500 Suspensions In case of replacement, proceed as follows: - Support the fork in a vice. - Insert the contrast plate in the upper end of the steering tube - Insert the special tool as shown in the figure.
  • Page 305 Nexus 500 Suspensions Refitting Reassembly of steering tapered bearing seats Using the special tool, reassemble the tapered bearing housings on the head as described below: - Place a new top housing on the head and a new bearing seat on the bottom side.
  • Page 306 Nexus 500 Suspensions Rear A= Connection of rear shock absorber to support connecting rod: 38 - 46 B = Strut upper connection: 56 - 70 C = Connection of front support strut and shock absorber to frame: 73 - 80 A = Connection of rear support strut to hub cover: 20-25 N·m...

  • Page 307: Removing The Rear Wheel

    Nexus 500 Suspensions - Preference for a higher rear section to improve handling and reduced speeds. Removing the rear wheel - Remove the muffler support arm - Remove the spacer on the gear shaft. - Loosen the five gear shaft fastening nuts using the rear brake.
  • Page 308 Nexus 500 Suspensions Swing-arm The scooter has engine-chassis rigid fixing system known as Direct-link. The system consists of: A= Left spacer B= Right-side engine support bearing C= Central spacer D= Right spacer E = Left side engine support bearing F = Chassis Removal - Adequately hold the engine.

  • Page 309: Shock Absorbers

    Nexus 500 Suspensions - 22 mm head bolts and washer. Shock absorbers Removal - To remove the rear shock absorber, remove the two retaining screws shown in the figure. Refitting - To refit perform the operation in reverse order carefully respecting the locking torques.

  • Page 310: Side Stand

    Nexus 500 Suspensions Side stand - Unhook the springs. - Loosen the nut. - Pull out the screw. Fitting Carry out the previous operations in reverse order. Locking torques (N*m) Side stand clamp 15 ÷ 20 SUSP - 18...
  • Page 311 INDEX OF TOPICS BRAK SYS RAKING SYSTEM...
  • Page 312 Nexus 500 Braking system Specifications The scooter has an integral brake system. This is obtained with the left-hand brake pump connected simultaneously to the rear brake calliper and the front right calliper. The connection to the rear calliper is direct.

  • Page 313: Rear Brake Calliper

    Nexus 500 Braking system Specification Desc./Quantity Rear brake pressure Front brake pressure Rear brake calliper Removal - Remove the rear wheel. - Remove the snap ring of the pad retaining pin. - Using a key, partially slide off the pad retaining pin until the circlip is released.
  • Page 314 Nexus 500 Braking system Overhaul - Remove the rear brake calliper - Suitably support the brake calliper in a vice - Remove the two calliper coupling screws as shown in the photograph. - Remove the two plungers from the calliper body with the aid of short blasts of compressed air through the brake fluid feed holes.
  • Page 315 Nexus 500 Braking system Refitting - The rear break calliper can be recognised by its Ø 34 mm plungers and the bleed screw as shown in the figure. - Insert the break pads in the pliers according to the arrow that indicates the break disc direction of rotation as shown in the photograph.
  • Page 316 Nexus 500 Braking system - Bleed the system and replace the rear wheel N.B. IF THE REAR BREAK CALLIPER SUPPORT PLATE HAS BEEN REMOVED, UPON REFITTING IT IS NECESSARY TO FOLD THE EDGES OF THE WASHER ON THE HEAD OF THE SCREWS FIXING THE PLATE TO THE CRANKCASE.
  • Page 317 Nexus 500 Braking system - Remove the two pistons from the calliper body with the aid of small blasts of compressed air through the brake fluid feeding hole. A piece of rubber pipe may be needed to seal with the com- pressor gun.
  • Page 318 Nexus 500 Braking system TO AVOID DAMAGING THE GASKETS, WASH THE PLIERS COMPONENTS ONLY WITH ALCO- HOL. DO NOT USE FUEL OR DERIVATIVES. Refitting - Attach the sliding plate of the front brake calliper to the fork using the two screws with lock washers tightened to the specified torque.
  • Page 319 Nexus 500 Braking system APPLYING AN EXCESSIVE QUANTITY OF GREASE MAY IMPAIR THE BRAKE PERFORM- ANCE Recommended products AGIP GREASE PV2 Grease for the steering bearings, pin seats and swinging arm White anhydrous-calcium based grease to protect roller bearings; temperature range between -20 C and +120 C;...

  • Page 320: Front Brake Disc

    Nexus 500 Braking system - If you detect incorrect values, replace the disc. If the anomaly persists, replace the hub. Front brake disc Removal - Remove the front wheel. - Adequately support the front wheel and remove the break disc operating on the five screws shown in the photograph.

  • Page 321: Front Brake Pads

    Nexus 500 Braking system - Repeat the measurement in at least 6 points of the disc. - Check that the measurements do not give devi- ations higher than ..- Remove the front brake caliper - Position the magnetic support base of the com- parator on the plate.
  • Page 322 Nexus 500 Braking system - Check that the thickness of the friction material is more than 1.5 mm. - Otherwise, replace it. Refitting - Assemble the brake pads into the calliper insert- ing the upper tip into the groove and pressing it towards the thrust spring to facilitate inserting the pin.
  • Page 323 Nexus 500 Braking system Rear brake pads Removal - Remove the rear brake calliper - Remove the brake pad and check there are no faults or warping. If it does, replace it. - Check that the thickness of the friction material is over 1.5 mm.
  • Page 324 Nexus 500 Braking system Rear - combined To bleed the integral system, first bleed the rear break calliper. - Remove the rubber cap from the bleed screw and insert a rubber pipe to recover the brake fluid. - With the left-had brake lever, load the system and bring it up to the required pressure.
  • Page 325 Nexus 500 Braking system Circuit bleed calliper fitting 12 - 16 Front - Remove the rubber hood from the bleed screw. - Insert a rubber pipe in the bleed screw to permit the brake fluid to be recovered. - With the right-hand brake lever, load the system and bring it up to the required pressure.
  • Page 326 Nexus 500 Braking system Removal - Remove the front handlebar cover. - Empty the braking system corresponding to the circuit being inspected. - Remove the two screws fixing the brake pump to the handlebar, indicated in the photograph. - Remove the oil pipe fitting from the pump undoing the screw indicated in the figure.
  • Page 327 Nexus 500 Braking system Removal Replace the pressure distribution valve If problems are discovered in the brake force dis- tribution between the front left brake calliper and the rear brake calliper (e.g. equal surface contact and braking of both the wheels, the rear brake en-...
  • Page 328 Nexus 500 Braking system - Tighten the screws fixing the valve to the chassis, but above all tighten the brake piping to the pre- scribed locking torques. - Fill and purge the braking system as described in the relevant section.
  • Page 329 INDEX OF TOPICS COOL SYS OOLING SYSTEM...
  • Page 330 Nexus 500 Cooling system Circuit diagram The cooling system is of the forced circulation type, with continuous venting and air pressurisation. Circulation takes places by a centrifugal pump driven by the countershaft. The pump delivers the coolant to the thermal unit.
  • Page 331 Nexus 500 Cooling system For the system venting during the circuit filling step, there is a special union at the top of the head (see filling rules). To ensure cooling in case of poor dynamic ventilation, there is an electric fan controlled by the injection system.
  • Page 332 Nexus 500 Cooling system - Select the menu on the "ACTIVE DIAGNOSIS" function and start the electric fan operation simu- lation (see "Injection" chapter). - If the electric fan is certainly efficient, check the ventilation start and end temperature. - Select the "PARAMETERS" function in the menu to display the coolant temperature.

  • Page 333: Coolant Replacement

    Nexus 500 Cooling system N.B. DO NOT USE OILS OR GREASES WHILE MOUNTING THE COOLING SYSTEM. FAILURE TO OB- SERVE THIS REGULATION CAN CAUSE IRREVERSIBLE DEFORMATION TO THE SEALING GASKETS. Coolant replacement System top-up rules - Prepare the mixture of 50% water and coolant.
  • Page 334 Nexus 500 Cooling system Water pump - overhaul - Check that the reed valve of blow-by circuit closes adequately. - Check that the water pump shaft does not show signs of wear and tear on the bearings in contact with the crankcase, in the oil seal area and on the motion sensor.
  • Page 335 Nexus 500 Cooling system - Check that the water pump cover is not damaged or deformed. - Check that the sealing O-Ring is in good condi- tion - Carefully position a new O-Ring, avoiding contact with grease or oil. CAUTION FAILURE TO OBSERVE THIS ADVICE CAN IRRETRIEVABLY DEFORM THE O-RING.
  • Page 336 Nexus 500 Cooling system - Check that the rotor does not show deformations or dents. - Check that the plastic rotor forms an integral unit with the metal part. Thermostat Check Before proceeding to disassembly, carry out a few checks: - Connect the diagnostic tester and select the «PA-...
  • Page 337 Nexus 500 Cooling system - Visually check that the thermostat does not have mechanical failures. - Prepare a metal container with ~ 1 litre of water. - Immerse the thermostat, and keep it in the middle of the container. - Immerse the multimeter thermometer probe close to the thermostat.
  • Page 338 Nexus 500 Cooling system There is also a valve that must allow air inlet during the cooling step. YES go to 2 NO go to 3 2 - Check the head gasket seal (see «Thermal group and timing system» chapter) 3 - Replace the cap.
  • Page 339 INDEX OF TOPICS CHAS HASSIS...
  • Page 340 Nexus 500 Chassis This section is devoted to the operations that can be carried out on the vehicle's bodywork. CAUTION NEVER CLEAN PAINTED PLASTIC PARTS WITH SOLVENTS CONTAINING PETROL OR ITS BY- PRODUCTS. Seat - Remove the saddle extracting the fixing pin of the gas shock absorber and the 2 chassis fixing screws.

  • Page 341: Instrument Panel

    Nexus 500 Chassis - Remove the frames of the brake pump on the left and right secured with 2 locking tabs. - Loosen the 4 retaining screws of the front han- dlebar cover with the handlebar proper. Remove the 4 pressure indicator lights from the warning light group, pulling them downwards.
  • Page 342 Nexus 500 Chassis Headlight assy. - Remove the centre cover of the shield. - Remove the 4 front retainers of the front light as- semblies. - To remove the right-hand light assembly, remove the screw located near the cover of the expansion tank.
  • Page 343 Nexus 500 Chassis Frame central cover - Remove the screw shown in the figure. - Disengage the 6 coupling teeth and remove the complete grid. - Remove the side cover. - Remove the saddle. - Remove the fuel port. - Remove the side grids.
  • Page 344 Nexus 500 Chassis - Remove the front shield, disconnecting the wiring and the connectors of the headlights and lights. Remove the 3 screws as shown in the figure. - Paying attention not to damage the plastic parts, release the 3 upper retainers of the windshield support and the 4 side retainers of the front shield.
  • Page 345 Nexus 500 Chassis - Remove the front fuse holder, levering out using a flat screwdriver on the tab located on the side (on the side of the key switch). - Remove the 2 screws located inside the storage compartment and the coolant top-up compartment (in order not to have to remove the front headlight).
  • Page 346 Nexus 500 Chassis Removing the ignition key-switch when on *off* - Remove the lower shield back plate. - Unscrew the seat opening transmission from the side. - Remove in advance the ring of the immobiliser antenna. - Loosen the 2 hex. socket head screws and re- move the complete switch.
  • Page 347 Nexus 500 Chassis Front wheel housing - Remove the spoiler. - Remove the front fork. - Remove the plate supporting bracket for the horn and voltage regulator by loosening the two retain- ing screws shown in the figure in order to release the two lower retainer of the wheel housing.
  • Page 348 Nexus 500 Chassis - Using a 10mm articulated wrench, between the under saddle compartment and the chassis tubes loosen the 2 rear fixing nuts, then disengage the stud bolts from the support tails. Footrest - Remove the centre union. - Remove the side fairings.
  • Page 349 Nexus 500 Chassis Side fairings - Remove the side rear union. - Remove the passenger handles. - Remove the bottom cover. - Remove the footboard supports - Remove the central union. - Remove the screws shown in the figure (in the left side, a screw is located below the air inlet union of the filter).
  • Page 350 Nexus 500 Chassis Air filter - Remove the helmet compartment. - Remove the straps of the oil vapour recovery hose and the air bellows shown in the figure. - Loosen the two screws shown in the figure. - Loosen the two retainers shown in the figure and remove the complete air filter.

  • Page 351: Rear Mudguard

    Nexus 500 Chassis Rear mudguard - Remove the two clamps shown in the figure. - Remove the retainer of the mudguard/strut rein- forcement plate to remove the complete mud- guard. Helmet bay - Remove the side panels - Remove the six upper clamping screws.
  • Page 352 Nexus 500 Chassis - Remove the 3 screws located inside the com- partment in the rear part providing the mounting for the electrical system of the saddle opening de- vice and for the support of the transmission. - Disconnect the connectors of the power socket and the under-saddle light.

  • Page 353: Fuel Tank

    Nexus 500 Chassis - Remove the 4 union screws with the front wheel housing cover. - Pull the spoiler from the lower part of the scooter. Fuel tank - Open the tank port. - Remove the hex screw shown in the figure.
  • Page 354 Nexus 500 Chassis N.B. THIS OPERATION SHOULD PREFERABLY BE PERFORMED WITH THE TANK EMPTY. - Remove the spoiler; - Remove the fuel filler. - Remove the two upper tank attachments high- lighted in the figure. - Remove the fuel pump retainers.

  • Page 355: Front Mudguard

    Nexus 500 Chassis Front mudguard - Remove the 4 retaining screws and pull the mud- guard towards the front of the scooter. - Pay attention during assembly to the correct po- sitioning of the retaining straps of the hoses. Radiator fan - Remove the spoiler.
  • Page 356 Nexus 500 Chassis Handles and top side fairings - Remove the three screws indicated in the figure. - Remove the 2 hex. socket head screws and then the passenger handgrips on the left and right. Flyscreen - Remove the 3 hex. socket head screws (when...
  • Page 357 Nexus 500 Chassis - Remove the plugs and remove the seals on the 2 lateral windshield support arms. - Remove the plastic cover from the windshield support, loosening the 5 screws shown in the fig- ure. - Disengage the 7 retaining tabs (3 with the shield back plate, 4 with the shield).

  • Page 358: Lower Cover

    Nexus 500 Chassis Battery - Remove the elastic strap and the battery cover. Lower cover - Remove the two rear screws shown in the figure. - Remove the 4 bottom screws shown in the figure and the complete bottom cover.
  • Page 359 INDEX OF TOPICS PRE DE DELIVERY...
  • Page 360 Nexus 500 Pre-delivery Carry out the listed tests before delivering the scooter. WARNING BE VERY CAREFUL WHEN HANDLING FUEL. Aesthetic inspection Appearance check: - Paintwork - Fitting of plastics - Scratches - Dirt Tightening torques inspection Lock check - Safety locks...
  • Page 361 Nexus 500 Pre-delivery CAUTION TO ENSURE MAXIMUM PERFORMANCE, THE BATTERY MUST BE CHARGED BEFORE USE. INADEQUATE CHARGING OF THE BATTERY WITH A LOW LEVEL OF ELECTROLYTE BEFORE IT IS FIRST USED SHORTENS THE LIFE OF THE BATTERY. CAUTION WHEN INSTALLING THE BATTERY, CONNECT THE POSITIVE CABLE BEFORE CONNECTING THE NEGATIVE ONE, AND PERFORM THE REVERSE OPERATION UPON REMOVAL.
  • Page 362 Nexus 500 Pre-delivery - Starter operation - Minimum hold (turning the handlebar) - Uniform turning of the steering - Possible leaks - Operation of the radiator electric fan Functional inspection Operating test: - Hydraulic brake system - Lever travel - Clutch - Check for correct operation...
  • Page 363 INDEX OF TOPICS TIME...
  • Page 364 Nexus 500 Time This section is devoted to the time necessary to carry out repairs. For each operation, the description, code and time envisages are specified. Engine ENGINE Code Action Duration 001001 Engine to chassis - Replace- ment TIME - 2...
  • Page 365 Nexus 500 Time Crankcase CRANKCASE Code Action Duration 001100 Oil seal, clutch side - Re- placement 001133 Engine crankcase- Replace- ment 001153 Crankcase half gasket - Re- placement TIME - 3...
  • Page 366 Nexus 500 Time Crankshaft CRANKSHAFT Code Action Duration 001117 Crankshaft - Replacement 001098 Countershaft - Replacement TIME - 4...
  • Page 367 Nexus 500 Time Cylinder assy. CYLINDER GROUP Code Action Duration 001002 Cylinder piston - Replace- ment 001154 Pin-ring-piston assembly - Service 001129 Chain tensioner - Service and Replacement TIME - 5...
  • Page 368 Nexus 500 Time Cylinder head assy. HEAD UNIT Code Action Duration 001045 Valves - Replacement 001049 Valves - Adjustments 001056 Head gasket - Replacement 001126 Head - Replacement 001083 Thermistor - Replacement 005116 revolution timing sensor - Re- placement 007012...
  • Page 369 Nexus 500 Time Rocker arms support assy. ROCKING LEVER SUPPORT UNIT Code Action Duration 001044 Camshaft - Replacement 001148 Rocking lever valve - Re- placement TIME - 7...
  • Page 370 Nexus 500 Time Cylinder head cover HEAD COVER Code Action Duration 001089 Head cover - Replacement 001093 Spark plug - Replacement 001088 Head cover gasket - Replace- ment TIME - 8...
  • Page 371 Nexus 500 Time Flywheel cover FLYWHEEL COVER Code Action Duration 001087 Flywheel cover - replace 001113 Water pump - Replacement 001123 Oil filter -Replacement 001124 By-pass valve - Replacement 001057 Thermostat - Replacement 001062 Water pump command shaft - Replacement...

  • Page 372: Driven Pulley

    Nexus 500 Time Driven pulley DRIVEN PULLEY Code Action Duration 001022 Clutch - Replacement 001012 Driven pulley - Overhaul 001110 Driven pulley - Replacement 001155 Clutch bell housing - Re- placement TIME - 10...
  • Page 373 Nexus 500 Time Oil pump OIL PUMP Code Action Duration 001042 Oil pump - overhaul 001051 Belt/ Timing chain - Replace- ment 001112 Oil pump - change 001125 Chain guide pads - change 001071 Start-up pinion - Replace- ment 001020...
  • Page 374 Nexus 500 Time Final gear assy. FINAL REDUCTION GEAR ASSEMBLY Code Action Duration 001010 Geared reduction unit - Serv- 001156 Gear reduction unit cover - Replacement 003065 Gear box oil - Replacement 004125 Rear gear shaft - Replace- ment TIME - 12...
  • Page 375 Nexus 500 Time Driving pulley DRIVING PULLEY Code Action Duration 001086 Driving half-pulley - Replace- ment 001011 Driving belt - Replacement 001006 Driving pulley - Service 001141 Belt anti-flapping roller - Re- placement 001066 driving pulley - Replacement TIME - 13...

  • Page 376: Transmission Cover

    Nexus 500 Time Transmission cover TRANSMISSION COVER Code Action Duration 001065 Internal transmission cover - Replacement 001096 External transmission cover - Replacement 001131 Transmission air intake - Re- placement 001135 Transmission cover bearing - Replacement 001170 Air manifold - replacement...

  • Page 377: Flywheel Magneto

    Nexus 500 Time Flywheel magneto MAGNETO FLYWHEEL Code Action Duration 001173 Rotor - replace 001067 Stator - Replacement 001058 Flywheel - Replacement 001104 Start-up freewheel - Replace- ment 001151 Start-up driven gearing - Re- placement TIME - 15...
  • Page 378 Nexus 500 Time Butterfly valve THROTTLE BODY Code Action Duration 001013 Intake manifold - change 001047 Injector - Replacement 001166 Throttle body - Replacement 004122 Cleaner / Throttle body union - Replacement 001171 Throttle body - Service/clean- TIME - 16...
  • Page 379 Nexus 500 Time Exhaust pipe SILENCER Code Action Duration 001009 Muffler - Replacement 001092 Exhaust manifold - Replace- ment 001095 Muffler guard - Replacement 001136 Exhaust emissions - Adjust- ment 004169 Muffler guard - Replacement TIME - 17...

  • Page 380: Air Cleaner

    Nexus 500 Time Air cleaner AIR CLEANER Code Action Duration 001015 Air filter box - change 001014 Air filter - Replacement/ Cleaning 001074 Oil vapour recovery pipe - Re- placement TIME - 18...
  • Page 381 Nexus 500 Time Frame FRAME Code Action Duration 004001 Frame - replace 004146 Front frame - Replacement 001032 Engine support pin - Replace- ment TIME - 19...
  • Page 382 Nexus 500 Time Centre-stand SIDE/CENTRAL STAND Code Action Duration 004004 Stand - Replacement 004102 Side stand - Replacement 005079 Side stand switch - Replace- ment 004171 Stand support plate - Re- placement TIME - 20...
  • Page 383 Nexus 500 Time Legshield spoiler FRONT SHIELD - SPOILER Code Action Duration 004066 Rear-view mirror - Replace- ment 005091 Turn indicator glass - Re- placement 005067 Front direction indicator bulb - Replacement 004064 Front shield - Replacement 004149 Shield central cover - Re-...
  • Page 384 Nexus 500 Time Central cover CENTRAL FRAME COVER Code Action Duration 004011 Central chassis cover - Re- placement 004104 Left side cover - Replace- ment 004105 Right side cover - Replace- ment 004079 Rear footrest - Replacement 004143 Footrest support - replace...
  • Page 385 Nexus 500 Time Mudguard MUDGUARDS Code Action Duration 004167 Grill / radiator cover - replace 004009 Rear mudguard - Replace- ment 004002 Front mudguard - change 003087 Wheel housing - Replace- ment TIME - 23...
  • Page 386 Nexus 500 Time Fuel tank FUEL TANK Code Action Duration 004005 Fuel tank - replace 004170 Tank filler neck - Replace- ment 004168 Fuel filler flap - Replacement 004109 Fuel tank breather - replace TIME - 24...

  • Page 387: Handlebar Covers

    Nexus 500 Time Handlebar covers HANDLEBAR COVERS Code Action Duration 004018 Handlebar front section - Re- placement 004019 Handlebar rear section - Re- placement 005129 Warning light group - Re- placement 004156 Glove-box flap - Replace- ment 005038 Instrument panel warning...
  • Page 388 Nexus 500 Time Handlebar components HANDLEBAR COMPONENTS Code Action Duration 003001 Handlebar - Replacement 005017 Stop switch - Replacement 002037 Brake or clutch lever - Re- placement 002060 Complete gas command - Replacement 002059 Right hand grip - Replace- ment...
  • Page 389 Nexus 500 Time Seat SADDLE Code Action Duration 004003 Saddle - Replacement 004150 Saddle shock absorber - Re- placement TIME - 27...
  • Page 390 Nexus 500 Time Locks LOCKS Code Action Duration 004010 Antitheft lock - Replacement 005099 Electric saddle opening de- vice - Replacement 002083 Saddle opening transmission - Replacement 002092 Seat locking transmission - replacement 004054 Saddle lock catch - Replace- ment...

  • Page 391: Turn Signal Lights

    Nexus 500 Time Turn signal lights REAR LIGHTS Code Action Duration 005005 Taillight - change 005022 Rear turn indicators - Re- placement 005068 Rear turn indicator bulb- Re- placement 005091 Turn indicator glass - Re- placement 005031 Licence plate light bulb - Re-...
  • Page 392 Nexus 500 Time FRONT LIGHTS Code Action Duration 005002 Front headlamp - replace 005008 Front headlamp bulbs - re- place 005044 Front lights cable unit - re- place TIME - 30...

  • Page 393: Front Wheel

    Nexus 500 Time Front wheel FRONT WHEEL Code Action Duration 005089 Tone wheel - Replacement 002041 Front brake disc - Replace- ment 003037 Front wheel rim- Replace- ment 003038 Front wheel axle - Replace- ment 003040 Front wheel bearings - Re-...

  • Page 394: Rear Wheel

    Nexus 500 Time LA MRM 2 (soap-based lithium grease with Mo- lybdenum disulphide). In the following points we indicate with an arrow the area to be greased (1 - Drive, 2 - Tone wheel) Rear wheel REAR WHEEL Code Action...
  • Page 395 Nexus 500 Time Fuel pump FUEL PUMP Code Action Duration 004073 Fuel pump - Replacement 004137 Injector pump pipe - Replace- ment TIME - 33...
  • Page 396 Nexus 500 Time Electric devices ELECTRIC DEVICES Code Action Duration 005001 Electrical system - Replace- ment 005054 Fuse holder - Replacement 005052 Fuse (1) - Replacement 005114 Electrical system - Service 005130 Electric control management device - Replacement TIME - 34...
  • Page 397 Nexus 500 Time ELECTRIC DEVICES Code Action Duration 001023 Injection control unit - Re- placement 005009 Voltage regulator - Replace- ment 005117 Electrical fan remote control - Replacement 005088 Emergency stop remote con- trol - Replacement 005096 Injection components remote...
  • Page 398 Nexus 500 Time ELECTRIC DEVICES Code Action Duration 005127 Overturn sensor - replace- ment 001069 H.V. coil - Replacement 005007 Battery - change 005046 Battery cover - change 005073 Immobilizer decoder - Re- placement 005011 Start-up remote control switch - Replacement...
  • Page 399 Nexus 500 Time HANDLEBAR ELECTRICAL COMPONENTS Code Action Duration 004035 Instrument panel - Replace- ment 005014 Odometer assembly - re- placement 005083 Board computer - replace- ment 003074 Handlebar right control - Re- placement 003075 Handlebar left control - Re-...
  • Page 400 Nexus 500 Time Helmet bay HELMET COMPARTMENT Code Action Duration 004016 Helmet compartment - re- place 005033 Glove-box light switch - Re- placement 005026 Helmet compartment light - Replacement 004142 Plug socket - Replacement 005027 Helmet compartment bulb support - Replacement...
  • Page 401 Nexus 500 Time Rear side fairings REAR COVERS Code Action Duration 004053 Spoiler - Replacement 004085 Rear fairing - Replacement 004068 Passenger handgrip - Re- placement 004159 Plates / Stickers - Replace- ment 004036 Lower chassis cover - Re- placement...

  • Page 402: Front Suspension

    Nexus 500 Time Front suspension FRONT SUSPENSION Code Action Duration 003051 Complete fork - replace 003010 Front suspension - service 003076 Fork housing - replacement 003079 Fork stem - Replacement 003048 Fork oil seal - Replacement 003073 Steering clearance - Adjust...

  • Page 403: Rear Suspension

    Nexus 500 Time Rear suspension REAR SUSPENSION Code Action Duration 003085 Suspension strut - Replace- ment 003007 Rear shock absorber - Re- placement 004120 Rear suspension linkage - Replacement 003086 Suspension strut support - re- placement TIME - 41...

  • Page 404: Cooling System

    Nexus 500 Time Cooling system COOLING SYSTEM Code Action Duration 007002 Water cooling radiator - Re- placement 007016 Fan with support - Replace- ment 007001 Expansion tank - Replace- ment 007024 Expansion tank cap - Re- placement 007019 Coolant return pipe - replace-...
  • Page 405 Nexus 500 Time Braking system BRAKE SYSTEM Code Action Duration 002021 Front brake piping - Replace- ment 002047 Front brake fluid and air bleeding system - replace 002020 Rear brake disc piping - Re- placement 002087 Rear integral braking system...
  • Page 406 Nexus 500 Time Code Action Duration 002068 Rear calliper - Service Windscreen WINDSHIELD Code Action Duration 004028 Windshield glass - Replace- ment 004101 Windscreen - Replacement 004117 Top fairing - Replacement TIME - 44...

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