APRILIA RS4 125 Service Station Manual
  1. Manuals
  2. Brands
  3. APRILIA Manuals
  4. Motorcycle
  5. RS4 125
  6. Service station manual

APRILIA RS4 125 Service Station Manual

Hide thumbs Also See for RS4 125:
Table of Contents

Advertisement

Quick Links

See also: Service Manual
SERVICE STATION MANUAL
B043126
RS4 125

Advertisement

Table of Contents
loading

Related Manuals for APRILIA RS4 125

Summary of Contents for APRILIA RS4 125

  • Page 1 SERVICE STATION MANUAL B043126 RS4 125...
  • Page 2 The descriptions and illustrations given in this publication are not binding; While the basic characteristics as described and illustrated in this booklet remain unchanged, Aprilia 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 SERVICE STATION MANUAL RS4 125 NOTE Provides key information to make the procedure easier to understand and carry out. CAUTION Refers to specific procedures to carry out for preventing damages to the vehicle. WARNING Refers to specific procedures to carry out to prevent injuries to the repairer.
  • Page 4 INDEX OF TOPICS CHAR HARACTERISTICS S-TOOLS PECIAL TOOLS MAIN AINTENANCE ELE SYS LECTRICAL SYSTEM ENG VE NGINE FROM VEHICLE NGINE P SUPP OWER SUPPLY SUSP USPENSIONS CHAS HASSIS BRAK SYS RAKING SYSTEM COOL SYS OOLING SYSTEM BODYW ODYWORK PRE DE DELIVERY...
  • Page 5 INDEX OF TOPICS CHAR HARACTERISTICS...

  • Page 6: Safety Rules

    RS4 125 Characteristics Rules Safety rules Carbon monoxide If you need to keep the engine running while working on the vehicle, please ensure that you do so in an open or very well ventilated area. Never run the engine in an enclosed area. If you do work in an enclosed area, make sure to use a fume extraction system.
  • Page 7 RS4 125 Characteristics KEEP OUT OF THE REACH OF CHILDREN DO NOT REMOVE THE RADIATOR CAP WHEN THE ENGINE IS STILL HOT. THE COOLANT IS UNDER PRESSURE AND MAY CAUSE BURNS. Used engine oil and transmission oil CAUTION IT IS ADVISABLE TO WEAR PROTECTIVE IMPERMEABLE GLOVES WHEN SERVICING THE VE- HICLE.
  • Page 8 REASSEMBLING COMPONENTS CAUTION BEARINGS MUST ROTATE FREELY, WITHOUT JAMMING AND/OR NOISE, OTHERWISE, THEY NEED TO BE REPLACED. • Only use ORIGINAL Aprilia SPARE PARTS. • Comply with lubricant and consumables use guidelines. • Lubricate parts (whenever possible) before reassembling them.

  • Page 9: Vehicle Identification

    RS4 125 Characteristics • If any signs of dirt, rust, moisture, etc. are noted, clean the inside of the connector carefully with a jet of compressed air. • Ensure that the cables are correctly fastened to the internal connector terminals.

  • Page 10: Engine

    RS4 125 Characteristics Chassis number The chassis number is stamped on the right hand side of the headstock. This number consists of numbers and letters, as in the example shown below. ZD4TW0000YSXXXXXX KEY: ZD4: WMI (World manufacturer identifier) code; TW: model;...

  • Page 11: Gear Ratios

    RS4 125 Characteristics Specification Desc./Quantity Cooling Coolant Valve clearance at intake 0.15 mm (0.0059 in) Exhaust valve clearance 0,25 mm (0.0098 in) GEAR Specification Desc./Quantity Type mechanic, 6-speed gearbox with pedal on the engine left side which operates the selector with fork and distribution drum.

  • Page 12: Warning Lights

    RS4 125 Characteristics Specification Desc./Quantity 2 daylight running lights 12V - 5W Turn indicator light Micro bulb Rpm indicator lighting 12 V - LED Rear daylight running light/stop light License plate lamp (where provided) 12V - 5W WARNING LIGHTS Specification Desc./Quantity...

  • Page 13: Tightening Torques

    RS4 125 Characteristics Supply FUEL SYSTEM Specification Desc./Quantity Fuel premium unleaded petrol as per DIN 51 607, minimum octane rating of 95 (NORM) and 85 (NOMM). Tightening Torques Chassis Front side RONT LIGHTS pos. Description Type Quantity Torque Notes Headlamp fixing screw M5x14 2.5 Nm (1.84 lbf ft)
  • Page 14 RS4 125 Characteristics TEERING pos. Description Type Quantity Torque Notes Upper yoke fastening to sleeve 25 Nm (18.43 lbf ft) Steering retainer nut 48 Nm (35.40 lbf ft) CHAR - 14...
  • Page 15 RS4 125 Characteristics RONT USPENSION pos. Description Type Quantity Torque Notes Screws fastening lower yoke to 25 Nm (8.43 lbf ft) sleeve RONT HEEL pos. Description Type Quantity Torque Notes Front wheel spindle nut 78 Nm (8.85 lbf ft) Front disc fixing screw M6x20 12 Nm (8.85 lbf ft)
  • Page 16 RS4 125 Characteristics RONT UDGUARD pos. Description Type Quantity Torque Notes Lug fixing screw M5x9 3 Nm (2.21 lbf ft) Side fairing fixing screw M6x12 6 Nm (4.42 lbf ft) Front mudguard fixing screw M6x25 4.4 Nm (3.24 lbf ft) 5 Nm (3.68 lbf ft)
  • Page 17 RS4 125 Characteristics IR DEFLECTORS pos. Description Type Quantity Torque Notes Radiator frame screw M5x16 2 Nm (1.47 lbf ft) Max 2.5 N (1.84 lbf Front fixing screw Self-t. 3.9 1 Nm (0.74 lbf ft) TCEI screw M5x20 2 Nm (1.47 lbf ft) Max 2.5 N (1.84 lbf...
  • Page 18 RS4 125 Characteristics ANDLEBAR AND ONTROLS pos. Description Type Quantity Torque Notes Semi-handlebar retainer M8x30 25 Nm (18.44 lbf ft) Loctite 243 Handlebar counterweight retainer M5x50 5 Nm (3.69 lbf ft) Loctite 243 NSTRUMENT PANEL pos. Description Type Quantity Torque...
  • Page 19 RS4 125 Characteristics RONT BRAKE PUMP pos. Description Type Quantity Torque Notes Front brake pump fixing screw 5 Nm (3.68 lbf ft) Brake pipe clamp fixing screw M5x16 5 Nm (3.68 lbf ft) RONT ALLIPER pos. Description Type Quantity Torque...
  • Page 20 RS4 125 Characteristics LUTCH CONTROL pos. Description Type Quantity Torque Notes Throttle cable ring fixing screw M6x16 6 Nm (4.42 lbf ft) Throttle control fixing screw M6x20 10 Nm (7.37 lbf ft) INDSHIELD pos. Description Type Quantity Torque Notes Rear view mirror fixing screw Self-t.
  • Page 21 RS4 125 Characteristics pos. Description Type Quantity Torque Notes Top fairing glass fixing screw 1 Nm (0.73 lbf ft) Central part CHASSIS pos. Description Type Quantity Torque Notes Support coil fixing screw 20 Nm (14.75 lbf ft) TCEI screw 25 Nm (18.43 lbf ft)
  • Page 22 RS4 125 Characteristics ODYWORK pos. Description Type Quantity Torque Notes Side fairing to chassis fixing screw M4x14 Plastic panel fixing screw M5x12 3 Nm (2.21 lbf ft) Side fairing to chassis fixing screw M5x9 3 Nm (2.21 lbf ft) Side fairing to chassis fixing screw M5x9 3 Nm (2.21 lbf ft)
  • Page 23 RS4 125 Characteristics pos. Description Type Quantity Torque Notes Rear tank fixing screw M8x40 25 Nm (18.44 lbf ft) Front tank fixing screw M6x35 10 Nm (7.37 lbf ft) Fastener screw M5x9 3 Nm (2.21 lbf ft) Tank cover fixing screw M5x9 3 Nm (2.21 lbf ft)
  • Page 24 RS4 125 Characteristics AIRINGS pos. Description Type Quantity Torque Notes Side fairing fixing screw M5x9 1.7 Nm (1.25 lbf ft) Max 2 Nm (1.47 lbf XHAUST pos. Description Type Quantity Torque Notes Drainage retainer M6x20 10 Nm (7.37 lbf ft)
  • Page 25 RS4 125 Characteristics ADIATOR pos. Description Type Quantity Torque Notes Radiator retainer M6x25 10 Nm (7.37 lbf ft) Expansion tank support fixing screw M6x20 3.5-4 Nm (2.58-2.95 lbf CHAR - 25...
  • Page 26 RS4 125 Characteristics OOTRESTS pos. Description Type Quantity Torque Notes Rider footrest support fixing screw M8x25 25 Nm (18.43 lbf ft) Loctite 243 Footrest protection fixing screw M5x12 5 Nm (3.69 lbf ft) Passenger footrest fixing screw M8x40 20 Nm (14.75 lbf ft)
  • Page 27 RS4 125 Characteristics ENTRAL ODYWORK pos. Description Type Quantity Torque Notes Fairing upper fixing screw M5x9 3 Nm (2.21 lbf ft) Fairing lower fixing screw M4x14 TAND pos. Description Type Quantity Torque Notes Thin nut M10x1.25 10 Nm (7.38 lb ft)
  • Page 28 RS4 125 Characteristics pos. Description Type Quantity Torque Notes TCEI screw M8x30 25 Nm (18.43 lb ft) Loctite 243 TCEI screw M8x45 25 Nm (18.43 lb ft) TE Screws Flang. M5x25 3 Nm (2.21 lb ft) TE Screws M6x30 10 Nm (7.38 lb ft) LOCKS pos.
  • Page 29 RS4 125 Characteristics Back side EAR SUSPENSION pos. Description Type Quantity Torque Notes Upper retainer 58 Nm (42.78 lbf ft) Lower retainer 58 Nm (42.78 lbf ft) Loctite 243 CHAR - 29...
  • Page 30 RS4 125 Characteristics WINGARM pos. Description Type Quantity Torque Notes Swingarm to chassis adjustment nut M25x1.5 15 Nm (11.06 lbf ft) Swingarm pin nut 78 Nm (57.52 lbf ft) Chainguard fixing screw M 4.8x13 1 Nm (0.74 lbf ft) Chainguard fixing screw Self-tap.
  • Page 31 RS4 125 Characteristics EAR LIGHTS pos. Description Type Quantity Torque Notes Turn indicator retainer 3 Nm (2.21 lbf ft) Turn indicator cover retainer 0.3 Nm (0.22 lbf ft) CHAR - 31...
  • Page 32 RS4 125 Characteristics EAR MUDGUARD pos. Description Type Quantity Torque Notes Rear mudguard to swingarm fixing Self-tap. 3 Nm (2.21 lbf ft) Max 4.5 Nm (3.31 screw lbf ft) Engine RANKSHAFT pos. Description Type Quantity Torque Notes Countershaft gear retainer nut 35 - 45 Nm (25.81 -...
  • Page 33 RS4 125 Characteristics YLINDER ISTON pos. Description Type Quantity Torque Notes Chain tensioner screw 6 Nm (4.43 lbf ft) HROTTLE BODY pos. Description Type Quantity Torque Notes Intake manifold fixing screw M6x20 10 Nm (7.38 lbf ft) CHAR - 33...
  • Page 34 RS4 125 Characteristics LUTCH COVER pos. Description Type Quantity Torque Notes Clutch cover fixing screw M6x35 11 - 13 Nm (8.11 - 9.58 lbf ft) Oil filter cover M56x1.5 24 - 26 Nm (17.70 - 19.17lbf ft) Oil pressure sensor 12 - 14 Nm (8.85 - 10.32...
  • Page 35 RS4 125 Characteristics EAD COVER pos. Description Type Quantity Torque Notes Spark plug 12 - 14 Nm (8.85 - 10.32 lbf ft) Head cover fixing screw 10 - 12 Nm (7.38 - 8.85 lbf ft) LYWHEEL COVER pos. Description Type...
  • Page 36 RS4 125 Characteristics IMING SYSTEM pos. Description Type Quantity Torque Notes Chain tensioner slider fulcrum fixing M6x16 10 Nm (7.38 lbf ft) Loctite 243 screw Transmission timing gear fixing M8x40 27 Nm (19.91 lbf ft) Loctite 243 screw CHAR - 36...
  • Page 37 RS4 125 Characteristics LUTCH pos. Description Type Quantity Torque Notes Clutch spring screw 3.5 - 4.5 Nm (2.58 - 3.31 lbf ft) Clutch housing retainer nut 35 - 45 Nm (25.81 - 33.19 lbf ft) TARTER OTOR pos. Description Type...
  • Page 38 RS4 125 Characteristics ATER PUMP pos. Description Type Quantity Torque Notes Water pump fixing screw 5 - 6 Nm (3.68 - 4.42 lbf pos. Description Type Quantity Torque Notes Oil pump fixing screw M6x25 10 Nm (7.38 lbf ft) Loctite 243...
  • Page 39 RS4 125 Characteristics EAR SELECTOR pos. Description Type Quantity Torque Notes Selector spider screw 3.5 - 4.5 Nm (2.58 - 3.31 lbf ft) Engaging lever screw 8 - 10 Nm (5.90 - 7.38 lbf CHAR - 39...
  • Page 40 RS4 125 Characteristics NGINE RANKCASE pos. Description Type Quantity Torque Notes Crankcase halves union 11 - 13 Nm (8.11 - 9.58 lbf ft) ALVES pos. Description Type Quantity Torque Notes Head fastener screw, chain side M6x130 11 Nm (8.11 lbf ft)
  • Page 41 RS4 125 Characteristics IGNITION UNIT pos. Description Type Quantity Torque Notes Flywheel rotor fixing screw M14x1.5 83 - 90 Nm (61.21 - 66.38 lb ft) EVERS pos. Description Type Quantity Torque Note Pinion retainer nut M12x1.25 30 Nm (22.12 lb ft)
  • Page 42 RS4 125 Characteristics pos. Description Type Quantity Torque Note Pinion cover fixing screw TEF M5x16 4 Nm (2.95 lb ft) Maximum torque: 5.0 Nm (3.68 lb ft) TCEI Screws pinion retainer M5x10 4 Nm (2.95 lb ft) Maximum torque: 5.0 Nm (3.68 lb ft) - Loct.
  • Page 43 RS4 125 Characteristics Recommended products chart RECOMMENDED PRODUCTS TABLE Product Description Specifications ENI I-RIDE PG 5W - 40 Engine oil SAE 5W - 40. As an alternative for rec- ommended oils, top-branded oils that meet or exceed the requirements of CCMC G-4 A.P.I.
  • Page 44 INDEX OF TOPICS S-TOOLS PECIAL TOOLS...
  • Page 45 RS4 125 Special tools PECIFIC TOOLS Stores code Description AP8140266 Dial gauge mounting 866380 Water pump tool set 865259 Flywheel retainer 864868 Flywheel extractor 020911Y Fitting adaptor engine RS 125 + 020710Y 864567 Locking pins timing camshafts S-TOOLS - 45...
  • Page 46 RS4 125 Special tools Stores code Description 864486 Blocking the countershaft 00H05600351 Guide for oil seal 020382Y011 Tool to remove/fit valves 020287Y tool for sealing ring fitting 865261 Piston locking pin 00H05300041 Clutch retainer 865260 Camshaft sprocket lock S-TOOLS - 46...
  • Page 47 RS4 125 Special tools Stores code Description 020376Y Adapter handle 020359Y 42 x 47-mm adaptor 020358Y 37 x 40-mm adaptor 020357Y 32 x 35 mm adaptor 020439Y Shaft 2 oil seal punch 17 mm 020891Y Adapter 25 mm (0.98 in)
  • Page 48 RS4 125 Special tools Stores code Description 020412Y Clutch oil seal punch D 15 mm 020375Y 28x30 mm punch 020483Y 30 mm guide 020364Y 25 mm Adaptor 866714 Swingarm adjustment S-TOOLS - 48...
  • Page 49 INDEX OF TOPICS MAIN AINTENANCE...

  • Page 50: Maintenance Chart

    Correct maintenance is fundamental for ensuring the longevity of your vehicle and maintaining optimum function and performance. To this end, Aprilia offers a set of checks and maintenance services (at the owner's expense), that are summarised in the table shown on the following page. Any minor faults must be reported without delay to an Authorised Aprilia Dealer or Sub-Dealer without waiting until the next scheduled service to solve it.
  • Page 51 RS4 125 Maintenance km(mi)x1000 (0.621) (3.728) (7.456) (1.184) (14.913) (18.641) (22.369) (26.097) (29.826) Callipers and brake disc Tyres Tyres pressure (4) Radiator - External cleaning Valve adjustment Odometer gear Wheels (4) Discharge Tightening screws Front suspension: oil (6) Warning lights...

  • Page 52: Engine Oil

    RS4 125 Maintenance Engine oil Check Check the engine oil level frequently. NOTE CARRY OUT MAINTENANCE OPERATIONS AT HALF THE INTERVALS SPECIFIED IF THE VEHICLE IS USED IN PAR- TICULAR RAINY OR DUSTY CONDITIONS, OFF ROAD OR FOR TRACK USE.

  • Page 53: Engine Oil Replacement

    RS4 125 Maintenance • Otherwise, top-up until the indicated level. Fill with engine oil as required: • Unscrew and remove the cap (1). When using a funnel or any other element, make sure it is perfectly clean. DO NOT ADD ADDITIVES OR OTHER SUBSTANCES TO THE OIL.

  • Page 54: Engine Oil Filter

    RS4 125 Maintenance • Drain the oil into the container; allow several minutes for oil to drain out com- pletely. • Remove any metal scrap attached to the drainage plug (2) magnet. • Check and, if necessary, replace the drainage plug (2) sealing washer.

  • Page 55: Gearbox Oil

    RS4 125 Maintenance • Unscrew and remove the oil filter plug. • Remove the spring and oil filter. Gearbox Oil Air filter • Remove the passenger saddle and collect the supporting rod of the fuel tank. • Lift the fuel tank and fasten it with the supporting rod.

  • Page 56: Cooling System

    RS4 125 Maintenance • Lower the tank, unscrew and remove the two screws (2) collecting the nuts underneath. • Operating on the rear area of the tank, lift the filter box cover (3) and sliding it together with the filtering element (4), making it slide upwards and back- wards.
  • Page 57 WHEN CARRYING OUT MAINTENANCE OPERATIONS, IT IS ADVISABLE TO WEAR LATEX GLOVES. TAKE YOUR SCOOTER TO AN OFFICIAL aprilia DEALER TO HAVE COOLANT CHANGED. Coolant solution is 50% water and 50% antifreeze fluid. This is the ideal mixture for most operating temperatures and provides good corrosion protection.

  • Page 58: Braking System

    IF THERE IS AN EXCESSIVE CONSUMPTION OF COOLANT OR WHEN THE EXPANSION TANK REMAINS EMPTY, CHECK THAT THERE ARE NO LEAKS IN THE CIRCUIT. NOTE FOR REPAIRS, CONTACT AN aprilia official Dealer. Once the check is performed, if necessary top up the cooling liquid; proceed as follow: •...
  • Page 59 RS4 125 Maintenance THE FLUID IN THE BRAKING CIRCUIT IS HYGROSCOPIC, THAT IS, IT ABSORBS MOISTURE FROM THE SUR- ROUNDING AIR. IF THE MOISTURE CONTENT IN THE BRAKE FLUID EXCEEDS A CERTAIN VALUE, WATER VA- POUR BUBBLES MAY FORM IN THE CIRCUIT, OR THE PUMP AND CALLIPERS MAY SEIZE, CAUSING THE BRAKES THEMSELVES TO SEIZE.
  • Page 60 RS4 125 Maintenance Top-up • The following operations refer to one braking system but they are valid for both braking systems: 1. Front brake fluid reservoir (1); 2. Rear brake fluid reservoir (2). CAUTION RISK OF BRAKE FLUID SPILLS. DO NOT PULL THE...
  • Page 61 RS4 125 Maintenance • In case of excessive travel of the brake lever or poor performance of the braking system, purge the air in the system. RISK OF BRAKE FLUID SPILLS. DO NOT OPERATE THE BRAKE LEVER WITH BRAKE FLUID RESERVOIR CAP LOOSENED OR REMOVED.

  • Page 62: Clutch System

    RS4 125 Maintenance level, that is between the two "MIN" and "MAX" reference marks. Clutch system Adjusting the lever Adjustment clutch when the engine stops or the vehicle tends to move forward even when clutch lever is operated and the gear engaged, or if the clutch "slides", resulting in acceleration delay con-...
  • Page 63 INDEX OF TOPICS ELE SYS LECTRICAL SYSTEM...
  • Page 64 RS4 125 Electrical system Components arrangement KEY: 1. Stop switch 2. Taillight 3. Injector ELE SYS - 64...
  • Page 65 RS4 125 Electrical system 4. Battery 5. Main fuses 6. Fan relay 7. Light relay 8. Front headlight assembly 9. Start-up relay 10.Electric fan 11.Lambda probe 12.Fuel reserve sensor 13.Oil pressure sensor 14.Fuel pump 15.Coil/ECU 16.Injection relay 17.Secondary fuses 18.Instrument panel 19.Turn indicators...
  • Page 66 RS4 125 Electrical system • No. 1 H.V. Cable • No. 1 Starter relays 12 V / 80 A • No. 3 Relays 12 V / 30 A Small parts and mountings: • No. 7 Large black clamps 290x4.5 (11.42x0.18 in) •...
  • Page 67 WIRING DIAGRAM Ensure that you have the most up to date electrical circuit diagram, downloading it from the network. Electrical circuit diagrams RS4 125 MY2011 - 898459. The installation is shown on the three ideal divi- sions of the vehicle: 1.
  • Page 68 RS4 125 Electrical system TABLE A2 - Running of headlight cables: left side 1. Daylight running light (5W). 2. Cable guide. 4. Low beam light 17. Turn indicator cable harness. 18. Headlight cable harness. TABLE A3 - Headlight cable running: right side 1.
  • Page 69 RS4 125 Electrical system TABLE A5 1. Daylight running light (5W). 4. Low beam light (35W). 6. High beam light (35W). TABLE B - SPEED SENSOR The speed sensor must be fixed with a clamp (11) on the clutch cable (9) and must be positioned with a wide radius bend in order to avoid damage.
  • Page 70 RS4 125 Electrical system C TABLES - LEFT AND RIGHT POSITIONING OF CABLES TABLE C1 12. Rubber clamp TABLE C2 12. Rubber clamp ELE SYS - 70...
  • Page 71 RS4 125 Electrical system D TABLES - SUPPORT TABLE D1 13. Clamp: the clamp must secure all cables inside the instrument holder support; the main cable har- ness must be secured with the clamp on the grey taping. 14. Main cable harness.
  • Page 72 RS4 125 Electrical system TABLE E - LIGHTS DETAIL 16. Clamps 17. Left light switch: The clamp must secure the light switch cable. 18. Right light switch: The clamp must secure the light switch cable. TABLE F - KEY SWITCH 19.
  • Page 73 RS4 125 Electrical system TABLE G - INSTRUMENT PANEL 21. Engine oil pressure warning light. TABLE H - REGULATOR POSITIONING 22. Main cable harness 23. Regulator CAUTION CHECK THE CORRECT CONNECTION OF THE REGULA- TOR. IN THE AREA HIGHLIGHTED IN RED (REGULATOR CA-...
  • Page 74 RS4 125 Electrical system TABLE I - FLYWHEEL POSITIONING CAUTION CHECK THE CORRECT CONNECTION OF THE FLY- WHEEL. ELE SYS - 74...
  • Page 75 RS4 125 Electrical system Central part TABLE A - PRE-FITTING CHASSIS TABLE A1 1. Retaining clip. 2. Cable guide. 3. Cable guide (throttle cable). TABLE A2 ELE SYS - 75...
  • Page 76 RS4 125 Electrical system TABLE A3 TABLE A4 TABLE A5 Free hole for chassis ground TABLE B - FUEL RESERVE PROBE PRE-FIT- TING 4. Fuel pump 5. Fuel reserve sensor ELE SYS - 76...
  • Page 77 RS4 125 Electrical system TABLE C 6. Main cable harness CAUTION THE ADHESIVE CABLE TIES (6) MUST BE POSITIONED WITH THE CABLE INTAKE OPENING UPWARD SO THAT THE CABLE HARNESS IS INSERTED FROM THE TOP SIDE. D TABLES - COIL PRE-FITTING - H.V. CABLE -...
  • Page 78 RS4 125 Electrical system TABLE E2 12. Protective rubber 13. Bracket retainer screw 14. Metallic bracket 15. Free hole for running injector cable and water sensor cable cable ties. CAUTION POSITION THE METAL BRACKET (14), BLOCKING THE ECU AND FIXING WITH SPECIFIC SCREW (13).
  • Page 79 RS4 125 Electrical system TABLE E5 19. Clamp CAUTION JOIN THE TWO CABLES (WATER SENSOR - INJECTOR), SECURE THEM WITH A CLAMP ANCHORING THEM TO THE METALLIC BRACKET THROUGH THE FREE HOLE ON THE BRACKET ITSELF. TABLE F - PRE-FITTING OF THE RADIATOR...
  • Page 80 RS4 125 Electrical system TABLE H - FUSES 21. Main fuses. 22. Auxiliary fuses. 23. Reserve fuses (auxiliary). 24. Reserve fuses (main) CAUTION POSITION THE FUSES ON THE METALLIC BRACKET OB- SERVING THE POSITION: - GREEN AND BROWN FUSES (RIGHT) - Main (21)
  • Page 81 RS4 125 Electrical system TABLE J - BATTERY AREA COMPONENTS TABLE J1 27. Turn indicators 28. 12V 30A Fan relay 29. 30A 12V Injection relay TABLE J2 30. Electric fan connector: insert the connector in the specific tongue in the battery support after con- necting it.
  • Page 82 RS4 125 Electrical system TABLE J4 • Correct positioning of the battery. TABLE J5 - RUNNING REAR BRAKE SENSOR ELE SYS - 82...
  • Page 83 RS4 125 Electrical system TABLE J6 32. Horn cable: the horn cable must be secured with the two indicated clamps. 33. Five clamps for fixing horn cable, stand sensor cable, neutral cable. 34. Neutral cable. 35. Stand sensor cable. TABLE K1 - Lambda probe and engine oil sen- sor cable run 36.
  • Page 84 RS4 125 Electrical system TABLE K2 - Starter motor cable run CAUTION ENSURE CORRECT CONNECTION (39); CHECK LOCKING OF THE GREY SECURITY LOCK. TABLE L - Starter motor cable run 40. Starter motor ground screw. 41. Starter motor positive screw.
  • Page 85 RS4 125 Electrical system N TABLES - Fuel tank cable harness TABLE N1 35. Fuel pipe 36. Clamp. 37. Fuel sensor and pump cable. 38. Clamps CAUTION ANCHOR THE CABLE HARNESS BRANCH (37) (FUEL RE- SERVE SENSOR AND PUMP) WITH THE FUEL HOSE (35), USING TWO CLAMPS (38) IN CORRESPONDENCE WITH THE GREY TAPINGS.
  • Page 86 RS4 125 Electrical system TABLE N3 6. Pre-fitted cable ties. 37. Fuel sensor and pump cable. CAUTION PASS THE BRANCH ON THE LEFT SIDE OF THE TANK, INSERTING IT ON THE SPECIFIC CABLE TIES (6) PREVI- OUSLY FITTED. TABLE N4 39.
  • Page 87 RS4 125 Electrical system TABLE O - QUICK SHIFT PREPARATION 42. The connector for Quick Shift preparation is not connected and should be left free. Back side TABLE A - REAR LIGHT PRE-FITTING 1. Grey sheathing that indicated the left turn indicator 2.
  • Page 88 RS4 125 Electrical system B TABLES - REAR LIGHT UNIT TABLE B1 1. Rear left turn indicator. 2a-2b. Faston: light blue and blue wires. 3a-3b. Faston: red and blue wires. 4. Rear left turn indicator cable harness run. 5. License plate frame cable harness 6.
  • Page 89 RS4 125 Electrical system TABLE C • Breather pipe D TABLES: DIAGNOSTICS CABLE DETAIL (STEPS FOR CORRECT FITTING) TABLE D1 - Step 1 TABLE D2 - Step 2 TABLE D3 9. Insert the diagnostics plug in the specific sup- port.
  • Page 90 RS4 125 Electrical system E TABLES - TAIL FAIRING CABLE HARNESS CLAMP TABLE E1 10. Pay close attention to the positioning of the cable harness. TABLE E2 11. Taillight Cable harness 12a. Clamps: join the taillight cable harness and the diagnostics cable.
  • Page 91 RS4 125 Electrical system TABLE E4 11. Taillight cable harness. 14. LED Rear light 15. Cable guide. ELE SYS - 91...
  • Page 92 RS4 125 Electrical system General wiring diagram 1. MULTIPLE CONNECTORS 2. ECU 3. FRONT LEFT TURN INDICATOR 4. TAIL LIGHT BULB ELE SYS - 92...
  • Page 93 RS4 125 Electrical system 5. LOW BEAM BULB 6. HIGH BEAM BULB 7. COMPLETE HEADLAMP 8. FRONT RIGHT TURN INDICATOR 9. SIDE STAND SWITCH 10.FAN 11.SPEED SENSOR 12.INSTRUMENT PANEL 13.CLUTCH SWITCH 14.TURN INDICATORS 15.LEFT LIGHT SWITCH 16.HORN 17.Right light switch 18.IGNITION SWITCH...
  • Page 94 RS4 125 Electrical system 43.Water Temperature Sensor 44.ECU DIAGNOSIS 45.- 46.- 47.ELECTRONIC TRANSMISSION 48.FUEL RESERVE SENSOR Colour key: Ar Orange Az Sky blue B Blue Bi White G Yellow Gr Grey M Brown N Black R Red Ro Pink V Green...
  • Page 95 RS4 125 Electrical system If the failure persists, check the alternator and the stator components as follows: After a sight control of the electrical connections, use a specific tester to measure the stator winding and the pick-up. If checks on the loading coil, pick-up detect irreg- ularities, replace the stator and the failing com- ponents.
  • Page 96 RS4 125 Electrical system • In case the circuit is interrupted the general warning light does not turn on, no icon and no reference notch turn on. Even when the tank is empty the low fuel warning light does not turn on.
  • Page 97 RS4 125 Electrical system Following the diagram indicated, it is possible to scroll through the display functions: • • TRIP I • TRIP II • The switch from km to miles is achieved by holding in the SET A (2) and SET B (1) buttons for ten seconds from 1 to 5 seconds after switching on the key.
  • Page 98 RS4 125 Electrical system Battery recharge circuit KEY: 1. MULTIPLE CONNECTORS 27. Battery 28. MAIN FUSES 30. Voltage regulator 31. ALTERNATOR RECHARGING SYSTEM • Disconnect the six-way connector (1) (black colour) located behind the left side cover. NOTE THE ENGINE SIDE IS IDENTIFIED WITH THE LETTER "A"...
  • Page 99 RS4 125 Electrical system Measurement of resistance (with engine off) • For a correct detection of the alternator resistance, an ambient temperature measurement must be carried out and afterwards a heat stabilisation (after turning fan on) by using a tester, using alternatively 3 of the 5 connector pins (no.
  • Page 100 RS4 125 Electrical system • Effective resistance stage 1 = 0.67-0.47 = 0.20 Ohm • If there is a significant difference between one stage and another (other than 0.20 Ohm), this means that the alternator is defective and must be replaced.
  • Page 101 RS4 125 Electrical system • If there is a significant difference between one stage and another (other than 15 V), this means that the alternator is defective and must be replaced. CAUTION WITH THE ENGINE HOT THE VALUES RECORDED ARE ON AVERAGE 4-5 V LESS THAN THOSE DETECTED WITH THE ENGINE COLD.
  • Page 102 RS4 125 Electrical system OLD SHORT CIRCUIT CURRENT 2000 4000 6000 8000 RMS DC current (Arms) (average of the 3 stage 12 - 18 12 - 18 12 - 18 12 - 18 currents) Voltage on battery poles with engine speed always between 3000 - 5000 RPM •...
  • Page 103 RS4 125 Electrical system Start-up system check KEY: 1. MULTIPLE CONNECTORS 2 ECU control unit 9. SIDE STAND 13. CLUTCH SWITCH 17. Right light switch 18. IGNITION SWITCH 25. START-UP RELAY 26. STARTER MOTOR 27. Battery 29. Secondary fuses 33. GEAR IN NEUTRAL SWITCH STARTER MOTOR - CHECK •...
  • Page 104 RS4 125 Electrical system START- UP RELAY CHECK • To check relay operation: • Supply 12 V voltage to the two male terminals (85 - 86). • Use a tester (in Ohm meter function) to check the circuit continuity between the other two terminals (87 - 30).
  • Page 105 RS4 125 Electrical system Horn control Testing voltage: 13 V (nominal 12 V) Input: < 3.5 A level indicators Sensor operation check • Lift the fuel tank. • Disconnect the connector. • With a tester check the values between the male terminals inside the connec- tor.
  • Page 106 RS4 125 Electrical system Lights list key: 1. Electronic instrument panel 2. Turn indicators 3. Left light switch 4. Rear right turn indicator 5. Twin tail light/stop light bulb 6. License plate light 7. Rear right turn indicator 8. Rear stop switch 9.
  • Page 107 RS4 125 Electrical system Operating voltage: Vdc 5÷20 V Maximum applicable voltage (for 1 minute): 24 V Maximum reverse voltage: -16 V Maximum power consumption: 10 mA (not includ- ing pull-up resistance) Maximum input current (sink): 20 mA Maximum output voltage - low level: 500 mV...

  • Page 108: Control Unit

    RS4 125 Electrical system Fuses AUXILIARY FUSES - 20A fuse: rear light unit, blinker, light relay, front headlight assembly - 15A fuse: start-up relay, injection relay, instru- ment panel, fan relay, control unit. - 20A and 15A fuses: spare fuses...
  • Page 109 RS4 125 Electrical system IN CASE OF A FAILURE IN THE BATTERY OR A BUMP STARTER, THE CORRECT OPERATION OF THE VEHICLE AND THE RESPECT FOR THE REGULATIONS IN FORCE ARE NOT GUARAN- TEED. WARNING BATTERY ELECTROLYTE IS TOXIC AND IT MAY CAUSE SERIOUS BURNS. IT CONTAINS SUL- PHURIC ACID.
  • Page 110 RS4 125 Electrical system Specific tooling 020333Y Single battery charger 020334Y Multiple battery charger WARNING BATTERY ELECTROLYTE IS TOXIC AND IT MAY CAUSE SERIOUS BURNS. IT CONTAINS SUL- PHURIC ACID. AVOID CONTACT WITH YOUR EYES, SKIN AND CLOTHING. IF IT ACCIDENTALLY COMES INTO CONTACT WITH YOUR EYES OR SKIN, WASH WITH ABUNDANT WATER FOR APPROX.
  • Page 111 RS4 125 Electrical system Make sure air bubbles are rising from all six filling holes. Leave the container in this position for 20 minutes or more. Note:If there are no air bubbles coming out of the filling holes, lightly tap the bottom of the container two or three times.
  • Page 112 RS4 125 Electrical system d - Press the red button, as shown in figure. e - Press the "MF" black button to activate the bat- tery recharge Maintenance Free as shown in fig- ure. f - Check the ignition of the green LED indicated with a red arrow in figure.

  • Page 113: Speed Sensor

    RS4 125 Electrical system h - Disconnect the clamps from the battery and check the voltage, if voltages are detected of less than 12.8 V, proceed with a new recharge of the battery starting from point c of the recharge pro-...
  • Page 114 RS4 125 Electrical system Maximum output voltage - high level: Vdc of the pull-up resistance Operating temperature range: -20÷60 °C (-4 °F÷ 140 °F) Function To indicate the vehicle speed by reading the front wheel turning speed. Operation / Operating principle Magnetoresistive sensor: generation of a square wave.
  • Page 115 RS4 125 Electrical system On the stator connector PIN 1 (+) and PIN 5 (-) are the ones relative to the engine speed sensor. Engine temperature sensor Resistance (PIN B1 - B2) to 25 °C (77 °F): 2.05 kOhm +/- 100 Ohm Resistance (PIN B1 - B2) to 60 °C (158 °F): 575...
  • Page 116 RS4 125 Electrical system ELECTRICAL ERRORS Engine temperature sensor P0115 - open circuit or shorted to positive / shorted to negative. Error cause Open circuit or shorted to positive: interruption of the circuit or excessive voltage at PIN 13 of the control unit connector.
  • Page 117 RS4 125 Electrical system Lambda sensor Function In charge of telling the control unit whether the mixture is lean or rich. Operation / Operating principle Based on the difference of oxygen in the exhaust fumes and the environment, this generates volt- age which is read and interpreted by the injection control unit.
  • Page 118 RS4 125 Electrical system • Verify continuity of the cabling between the sensor connector and the control unit connector: Control unit PIN 11 - sensor PIN C and control unit PIN 12 - sensor PIN D. Restore the cabling if necessary.

  • Page 119: Fuel Pump

    RS4 125 Electrical system Injector Function To supply the correct amount of petrol at the right timing. Operation / Operating principle Injector coil is excited for the petrol passage to open. Pin-out: 1. Control unit ground 2. Relay powered CAUTION...
  • Page 120 RS4 125 Electrical system ELECTRICAL ERRORS Fuel pump relay P0230 - shorted to positive / shorted to negative / open circuit. Error cause Shorted to positive: excessive voltage at PIN 22 of the control unit connector. Shorted to negative: null voltage at PIN 2 of the injection relay.
  • Page 121 RS4 125 Electrical system Check A tester can be used for the check. In every case the continuity of the primary and secondary wind- ings must be checked. The reading in ohms does not need to be exact but, if the windings are intact, their continuity must be detected with the resist- ance values indicated above.
  • Page 122 RS4 125 Electrical system • Verify, with the key turned ON, the presence of voltage on the coil connector PIN 1. If no voltage is read, verify the continuity of the cabling between coil and injection relay (No. 35 on the electrical circuit diagram): Coil PIN 1 - relay PIN 3.
  • Page 123 RS4 125 Electrical system BEFORE CARRYING OUT ANY TROUBLESHOOTING, CAREFULLY READ THE GENERAL TROU- BLESHOOTING CONCEPTS FOR ELECTRICAL DEVICES AT THE BEGINNING OF THE CHECK AND CONTROL SECTION IN THE ELECTRICAL SYSTEM CHAPTER. ELECTRICAL ERRORS Fan relay P0480 - shorted to positive / shorted to negative / open circuit.
  • Page 124 RS4 125 Electrical system 1. COIL (orange - white) 2. INSTRUMENT PANEL (grey - blue) 3. NEUTRAL SENSOR (green - black) 4. RIGHT LIGHT SWITCH (pink - yellow) 5. RIGHT LIGHT SWITCH (yellow - red) 6. ECU CONTROL UNIT (green - red) 7.
  • Page 125 RS4 125 Electrical system 34.INJECTOR (grey - red) Dashboard key: 1. GROUND 2. + LIVE 3. (Not connected) 4. GROUND FOR SENSORS 5. RIGHT TURN INDICATOR WARNING LIGHT 6. EFI WARNING LIGHT 7. HIGH BEAM WARNING LIGHT 8. LEFT TURN INDICATOR WARNING LIGHT 9.
  • Page 126 INDEX OF TOPICS ENG VE NGINE FROM VEHICLE...
  • Page 127 RS4 125 Engine from vehicle Vehicle preparation • Rest the vehicle on its stand • Support the vehicle rear part using belts and hoist. • Drain off the cooling system. • Beforehand, remove the lug, the side fairings, the battery, the fuel tank, the side fairings, the drive chain, the air filter box, the radiator and the expansion tank.
  • Page 128 RS4 125 Engine from vehicle Vehicle preparation • Unhook the clutch cable and free it from the cable grommet. • Undo and remove the screw and dis- connect the starter ground cable. • Remove the rubber plug and loosen the screw.
  • Page 129 RS4 125 Engine from vehicle • Unhook the chain and remove it. • Water temperature connector. • Disconnect the neutral sensor connec- • Remove the oil temperature sensor. ENG VE - 129...
  • Page 130 RS4 125 Engine from vehicle • Remove the oil temperature sensor. • Remove the battery compartment. • Remove the coil. • Remove the clamp. • Remove the breather pipe. ENG VE - 130...
  • Page 131 RS4 125 Engine from vehicle • Remove the screw. • Remove the cable guide. • Disconnect the injector connector. • Remove the main cable harness cable grommet. • Working on both sides, unscrew and remove the two fixing screws. ENG VE - 131...
  • Page 132 RS4 125 Engine from vehicle • Secure the vehicle adequately. • - Working on the left side, loosen the swingarm pin. • Operating from both sides, remove the pass through screws and collect the retaining nuts. • Operating from both sides, remove the upper fixing screws.
  • Page 133 RS4 125 Engine from vehicle • Collect the ring nut. Installing the engine to the vehicle • Place the ring nut and tighten it to the prescribed torque. Specific tooling 866714 Swingarm adjustment • Insert the swingarm pin from the right side and slide it until it reaches the oth- er side.
  • Page 134 RS4 125 Engine from vehicle • Working from both sides, start the through screw with the nut. • Tighten the screws to the prescribed torque. • On the left side place the washer on the swingarm pin and start the nut.
  • Page 135 RS4 125 Engine from vehicle • Connect the injector connector to the main cable harness. • Place the cable guide. • Tighten the screw to the prescribed tor- que. • Place the breather pipe and secure it with the clamp.
  • Page 136 RS4 125 Engine from vehicle • Place the battery compartment and in- sert the relays in the appropriate seats. • Tighten the battery compartment screw to the prescribed torque. • Connect the horn. • Connect the oil temperature sensor. •...
  • Page 137 RS4 125 Engine from vehicle • Connect the water temperature sen- sor. • Place and reconnect the chain. • Place the gear lever and tighten the screw to the prescribed torque. • Place the pinion cover and tighten the two screws to the prescribed torque.
  • Page 138 RS4 125 Engine from vehicle • Connect the starter motor cable and tighten the screw to the prescribed tor- que. • Fit the rubber hose. • Connect the starter motor ground wire and tighten the screw to the prescribed torque.
  • Page 139 INDEX OF TOPICS NGINE...
  • Page 140 RS4 125 Engine Gearbox Gearbox shafts Disassembling the gearbox • Open the crankcase halves. • Remove the gaskets from the crank- case. • Take out both fork rods and the trans- mission forks (1) (2). • Take out the desmodromic control (3).
  • Page 141 RS4 125 Engine THE CLASS AS WELL AS BEING REPRODUCED ON TWO COUPLING ELEMENTS IS ALSO SHOWN ON THE TWO CRANKCASE HALVES OF THE CRANKCASE. NOTE CRANKCASE SPARE PARTS ARE ALWAYS CLASS X. Checking the desmodromic drum • Check the contact zone on fork (1) and the driving pin (2) of the forks for wear.

  • Page 142: Starter Motor

    RS4 125 Engine • Position the desmodromic drum in the crankcase (3). • Fit the two axles of the transmission forks (1)(2). • Fit the two transmission forks. • Finally, fit the crankshaft. Specific tooling 00H05600351 Guide for oil seal...
  • Page 143 RS4 125 Engine Removing the starter motor • Undo and remove the two fixing screws (1). • Remove the starter motor (2). NOTE THE STARTER MOTOR CAN ALSO BE REMOVED IF THE ENGINE IS FITTED TO THE VEHICLE. Installing the starter motor •...
  • Page 144 RS4 125 Engine pos. Description Type Quantity Torque Notes Timing control cover 3.5 - 4.5 Nm (2.58 - 3.31 lbf ft) Oil dipstick M12x1.5 4 - 6 Nm (2.95 - 4.42 lbf IGNITION UNIT pos. Description Type Quantity Torque Notes Flywheel rotor fixing screw M14x1.5...
  • Page 145 RS4 125 Engine Magneto flywheel removal • Remove the starter motor gear. • Position the locking tool. • Unscrew and remove the hex head screw and retrieve the washer. Specific tooling 865259 Flywheel retainer • Position the tool. • Remove the flywheel and its spline.
  • Page 146 RS4 125 Engine • Remove the oil filter. ENG - 146...
  • Page 147 RS4 125 Engine Freewheel removal • Undo and remove the screw from the lock. • Remove the freewheel. Installing the flywheel For refitting follow the operations described previously in reverse order. See also Magneto flywheel removal ENG - 147...
  • Page 148 RS4 125 Engine Clutch side LUTCH COVER pos. Description Type Quantity Torque Notes Clutch cover fixing screw M6x35 11 - 13 Nm (8.11 - 9.58 lbf ft) Oil filter cover M56x1.5 24 - 26 Nm (17.70 - 19.17lbf ft) Oil pressure sensor 12 - 14 Nm (8.85 - 10.32...
  • Page 149 RS4 125 Engine LUTCH pos. Description Type Quantity Torque Notes Clutch spring screw 3.5 - 4.5 Nm (2.58 - 3.31 lbf ft) Clutch housing retainer nut 35 - 45 Nm (25.81 - 33.19 lbf ft) Removing the clutch cover •...
  • Page 150 RS4 125 Engine • Unscrew and remove the oil filter plug. • Remove the spring and oil filter. ENG - 150...
  • Page 151 RS4 125 Engine • Unscrew and remove the ten clutch cover screws. • Remove the clutch cover and the gas- ket. • Collect the dowel pins. WARNING REPLACE THE GASKET DURING REFITTING. • Remove the lubrication circuit by-pass spring. Disassembling the clutch •...
  • Page 152 RS4 125 Engine • Remove the thrust bearing. • Remove the discs. • Release the screw by lowering the lock tab. • Block clutch bell rotation using the spe- cific tool. • Unscrew and remove the clutch bell fixing nut.

  • Page 153: Checking The Clutch Plates

    RS4 125 Engine • Remove the shim. Checking the clutch plates Characteristic Driving plates thickness 2.85 - 2.95 mm (0.112 - 0.116 in) Number of driving plates Driven plates thickness 1.46 - 1.53 mm (0.057 - 0.06 in) Number of driven plates...
  • Page 154 RS4 125 Engine Check the primary driven gear for damage and wear and, if necessary, replace the primary driven gear and the clutch bell all together. Make sure there is not excessive noise during op- eration; if necessary, replace the primary drive gear and the clutch bell all together.
  • Page 155 RS4 125 Engine Checking the springs • Check the springs for damage and, if necessary, replace the them all togeth- • Measure the clutch spring length when unloaded; if necessary, replace the springs all together. Characteristic Minimum wear limit in the release position of the individual clutch springs 31.6 mm (1.24 in)
  • Page 156 RS4 125 Engine • Insert the clutch hub. • Screw in the retainer nut locking the rotation of the clutch housing with the specific tool. Specific tooling 00H05300041 Clutch retainer • Lift one side of the lock tab. • Insert the disc covered with the friction material into the bell.
  • Page 157 RS4 125 Engine • Insert a new gasket. • Position the dowel pins and the cover. • Position the clutch cable support. • Screw in the ten screws, tightening di- agonally and in stages. • Refit the water pump. •...
  • Page 158 RS4 125 Engine RANKSHAFT pos. Description Type Quantity Torque Notes Countershaft gear retainer nut 35 - 45 Nm (25.81 - 33.19 lbf ft) Balancing countershaft removal • Before taking out the balancing coun- tershaft the clutch cover and flywheel cover must be removed.
  • Page 159 RS4 125 Engine Removing the clutch cover Removing the flywheel cover • Remove the countershaft gear. • Remove the countershaft from the al- ternator side. Balancing countershaft fitting • Insert the countershaft from the alter- nator side. • Insert the gear aligning its reference to the primary gear.
  • Page 160 RS4 125 Engine Crankcase opening • Beforehand remove the clutch cover and the clutch. • Remove the gear selector. • Install the countershaft blocking tool. Specific tooling 864486 Blocking the countershaft • Remove the primary gear unscrewing and removing the nut.
  • Page 161 RS4 125 Engine cylinder • Remove the chain guide slider, un- screwing and removing the fixing screw. • Remove the timing chain gear. • Remove the pump drive gear, remov- ing the seeger and recovering the washer. • Remove the base gear of the main shaft.
  • Page 162 RS4 125 Engine • Remove the oil pump unscrewing the three fixing screws. • Collect the gasket. • Remove the gear spider screw, un- screwing and removing the fixing screw. • Moving from the left side of the engine, remove the flywheel and all of its com- ponents beforehand.
  • Page 163 RS4 125 Engine • Unscrew and remove the five screws (3). • Unscrew and remove the short screw (4). • Remove the left crankcase. Bearing removal • Heat the crankcase surface with a heat gun. • Remove the bearing using the specific extractor.
  • Page 164 RS4 125 Engine • Insertion of secondary shaft roller bearing cage: 020363Y Removal of the secondary shaft roller bearing cage: use universal extractor • Insertion of countershaft roller bearing cage: 020483Y Removal of countershaft roller bear- ing cage: 020364Y Crankcase check There are two classes of couplings highlighted on the crankcases (X-Y and S-T).
  • Page 165 RS4 125 Engine Therefore, the couplings will be: COUPLING CLASSES FIRST GEAR SHAFT - BALANCING COUNTERSHAFT Coupling classes on Crankcase Transmission gear Balancing countershaft gear The classes of the transmission elements are also listed on the two crankcase halves. NOTE CRANKCASE SPARE PARTS ARE ALWAYS CLASS X.
  • Page 166 RS4 125 Engine • Check that the surfaces that limit crankshaft axial clearance show no signs of wear. To measure and check sizes follow the procedure described previously for checking crankshaft axial clearance and dimensions. Balancing countershaft check COUPLING CLASSES The gears that are coupled to each other: clutch housing, first gear shaft and balancing countershaft, indicate the coupling classes;...
  • Page 167 RS4 125 Engine • Insertion of desmo bearing: 020439Y+020357Y Removal of desmo bearing: 020891Y • Insertion of secondary shaft roller bearing cage: 020891Y Removal of the secondary shaft roller bearing cage:020363Y • Insertion of countershaft bearing: 020412Y+020358Y Removal of countershaft bearing:...
  • Page 168 RS4 125 Engine • Position and screw the long screw (2). • Moving from the left side of the crank- case, position and screw the six screws (1). • Fit the countershaft. • Position the selection spider screw. • Position and screw the screw.
  • Page 169 RS4 125 Engine • Insert the countershaft gear and posi- tion the washer. • Use the specific tool to tighten the nut. • Apply the cotter to the main shaft. • Position the base gear of the primary, aligning the two references.
  • Page 170 RS4 125 Engine • Insert the timing chain gear, paying at- tention to the direction. The engraving must face upward. • Fit the timing chain. • Position the chain guide slider. • Position and screw the fixing screw. • Fit the rest of the primary gears.
  • Page 171 RS4 125 Engine Head and timing EAD COVER pos. Description Type Quantity Torque Notes Spark plug 12 - 14 Nm (8.85 - 10.32 lbf ft) Head cover fixing screw 10 - 12 Nm (7.38 - 8.85 lbf ft) ENG - 171...
  • Page 172 RS4 125 Engine ALVES pos. Description Type Quantity Torque Notes Head fastener screw, chain side M6x130 11 Nm (8.11 lbf ft) Exhaust side fixing stud bolt M8x40 12 Nm (8.85 lbf ft) Camshaft support fixing screw M6x40 10 Nm (7.38 lbf ft)
  • Page 173 RS4 125 Engine • Unscrew and remove the four cylinder head screws (2). • Remove the cylinder head (3). • Remove the gasket (4). • Remove the spark plug. ENG - 173...
  • Page 174 RS4 125 Engine Removing the timing control • Turn the crankshaft from the hole on the cover (1) • Take the piston to TDC. • The sign (2) must be aligned with the sign (3). • Insert the specific pins (4) on the valves cam tower.

  • Page 175: Cylinder Head

    RS4 125 Engine • Lock the timing gear using the specific tool. Specific tooling 865260 Camshaft sprocket lock • Unscrew and remove the gear. • Repeat the operation with the other gear. Cylinder head Removing the overhead camshaft • Unscrew and remove the six screws (1) and (2).
  • Page 176 RS4 125 Engine • Remove the cylinder head (3). • Remove the two pins from the valves cam tower. • Remove the eight screws (1). • Remove the valve cam tower (2). • Remove the two camshafts, intake and exhaust side.

  • Page 177: Removing The Valves

    RS4 125 Engine Removing the valves • Remove the head. • Place the head on supporting surface. • Number the valves and their bucket tappets in order to position them cor- rectly upon refitting. • Remove the valve bucket tappets.
  • Page 178 RS4 125 Engine • Release the valve springs. • Remove the cap and the valve spring. Checking the overhead camshaft • Check the camshaft bearings for signs of abnormal wear. Characteristic Standard diameter - Bearing A 19.980 - 19.959 mm (0.7866 - 0.7858 in) Minimum diameter allowed - Bearing A 19.95 mm (0.7854 in)
  • Page 179 RS4 125 Engine 3.95 mm (0.1555 in) Standard clearance - Intake: 0.015/0.042 mm (0.00059/ 0.0016 in) Standard clearance - Exhaust: 0.025/0.052 mm (0.00098/ 0.00204 in) Maximum clearance admitted - Intake: 0.060 mm (0.0023 in) Maximum clearance admitted - Exhaust: 0.070 mm (0.0027 in) •...
  • Page 180 RS4 125 Engine • Use a feeler gauge to check clearance on the four valves. • If the values measured differ from the values specified, record the difference between MAXIMUM ALLOWED CLEARANCE e CLEARANCE MEAS- URED. • Remove the chain tensioner.
  • Page 181 RS4 125 Engine • Remove the bucket tappet of the valve in question and read the calibration val- ue for that bowl, found inside the buck- et tappet itself. • Replace the bucket tappet with new one of a size suitable to restore the correct clearance.
  • Page 182 RS4 125 Engine - Measure the sealing surface width on the valve seats. VALVE SEALING SURFACE Specification Desc./Quantity Inlet valve - seal surface 2.30 +/- 0.15 mm (0.0905 +/- 0.0059 in) Outlet valve - seal surface 2.95 +/- 0.15 mm (0.1161 +/- 0.0059 in) Valve chamfering 0.2 +/- 0.1 mm x 45°...

  • Page 183: Checking The Cylinder Head

    RS4 125 Engine Inspecting the springs and half-cones • Check that the spring upper supporting caps and the cotters show no signs of abnormal wear. • Check the unloaded spring length. Characteristic Valve spring length: 33.24 +/- 0.25 mm (1.3086 +/-0.0098 in) Checking the cylinder head •...
  • Page 184 RS4 125 Engine Checking the chain tensioner CHAIN TENSIONER • Remove the central 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 signs of wear are found, replace the whole assembly.
  • Page 185 RS4 125 Engine YLINDER ISTON pos. Description Type Quantity Torque Notes Chain tensioner screw 6 Nm (4.43 lbf ft) Removing the cylinder CYLINDER REMOVAL • Remove the cylinder head gasket (1). • Remove the guide slider (2). • Remove the water sleeve clamp (3).
  • Page 186 RS4 125 Engine • Remove the cylinder (4). • Remove the gasket (5). Disassembling the piston • Apply the tool under the piston (1). • Cover the base of the cylinder with a cloth. Specific tooling 865261 Piston locking pin •...
  • Page 187 RS4 125 Engine Checking the piston • Measure the pin seat diameter on the piston. • Calculate the pin - piston coupling clearance. • Measure the piston outside diameter, perpendicular to the pin axis. • Take the measurement at 6 mm (0.24 in) from the base, at the position shown in the figure.
  • Page 188 RS4 125 Engine - top ring: +0.03 / 0.062 mm (0.0012 / 0.0024 in) - middle ring: +0.02 / 0.052 mm (0.0008 / 0.0020 in) - oil scraper: +0.01 / 0.19 mm (0.0004 / 0.007480 in) cylinder check • Using a bore meter, measure the cyl-...
  • Page 189 RS4 125 Engine Specification Desc./Quantity Oil scraper ring 0.2 / 0.7 mm (0.0079 / 0.027 in) Top ring maximum value 0.45 mm (0.18 in) Middle ring maximum value 0.45 mm (0.18 in) Checking the connecting rod small end • Measure the inside diameter of the connecting rod small end using a spe- cific micrometer.
  • Page 190 RS4 125 Engine • Temporarily install the cylinder on the piston, without the gasket of the cylin- der's base. • Fit a dial gauge on the specific tool. • Take the piston to TDC. • Position the dial gauge on one side of the cylinder and fasten it in order to de- tect the zero position correctly.

  • Page 191: Installing The Cylinder Head

    RS4 125 Engine • Fit a new gasket between the cylinder and the head. • Place the two dowels. • Install the head. Selecting the base gasket BASE GASKET SELECTION Specification Desc./Quantity Size measured: 0.95 / 1.09 mm (0.037 - 0.042 in) Gasket 0.3+/-0.05 mm (0.012+/-0.001 in)
  • Page 192 RS4 125 Engine • Insert the timing control chain on the crankshaft. • Insert the chain tensioner pad of the head and lock it with the fixing screw. • Insert the camshafts in their seats on the head, remember to position the...
  • Page 193 RS4 125 Engine • Place the camshaft gears on the chain, be careful not to invert the original di- rection of rotation. • Keep the camshafts locked with the pins and screw but do not tighten the screws fixing the gears using Loctite 243.
  • Page 194 RS4 125 Engine Lubrication pos. Description Type Quantity Torque Notes Oil pump fixing screw M6x25 10 Nm (7.38 lbf ft) Loctite 243 ENG - 194...
  • Page 195 RS4 125 Engine Conceptual diagrams Removing • Remove the Seeger ring. • Remove the pump gear. ENG - 195...
  • Page 196 RS4 125 Engine • Remove the pump gear. • Separate the components to inspect them. Inspection • Measure distance between rotors with a feeler gauge at the positions shown in the picture. Characteristic Oil intake rotor Thickness: 13.5 mm (0.53 in) Oil supply rotor Thickness: 8.5 mm (0.33 in)
  • Page 197 RS4 125 Engine Installing • Refit the oil pump proceeding in re- verse order of disassembly. Pay atten- tion to the direction of the rotor, the dot should stay on the opposite part of the resting face. ENG - 197...
  • Page 198 INDEX OF TOPICS P SUPP OWER SUPPLY...
  • Page 199 RS4 125 Power supply Circuit diagram key: 1. Fuel tank 2. Fuel pump 3. Fuel pump ring nut 4. Fuel pump gasket 5. Fuel pipe 6. Fuel level sensor 7. Tank opening rod 8. Fuel breather pipe Fuel pump P SUPP - 199...
  • Page 200 RS4 125 Power supply Removing Remove and empty the fuel tank. • Remove the fuel hose (4). • Loosen the ring nut (3) and slide off the gasket (2). • Remove the pump (1). See also Fuel tank Injection P SUPP - 200...
  • Page 201 RS4 125 Power supply Diagram 1. ECU control unit position 2. Ignition switch 3. Fuel pump 4. Instrument panel P SUPP - 201...
  • Page 202 RS4 125 Power supply 5. Air temperature sensor 6. Throttle valve position sensor 7. Injector 8. Coolant temperature sensor 9. Lambda probe position 10.Engine revolution sensor 11.Electric fan Removing the throttle body • Remove the filter box. • Loosen and remove the nut and un- hook the throttle cable.
  • Page 203 RS4 125 Power supply • Loosen the clamp and remove the throttle body. P SUPP - 203...
  • Page 204 INDEX OF TOPICS SUSP USPENSIONS...
  • Page 205 RS4 125 Suspensions Front RONT USPENSION pos. Description Type Quantity Torque Notes Screws fastening lower yoke to 25 Nm (8.43 lbf ft) sleeve Key: SUSP - 205...
  • Page 206 RS4 125 Suspensions 1. Front tyre 2. Wheel bolt special screw 3. Washer 4. TE flanged screw 5. Front brake disc 6. Front wheel right external spacer 7. Sealing ring 8. Circlip 9. Bearing 10.Internal spacer 11.Bare front wheel 12.Front wheel pin 13.Tubeless valve...

  • Page 207: Removing The Front Wheel

    RS4 125 Suspensions Removing the front wheel • Support the vehicle at the front, by fas- tening a suitable belt to the handlebar and a crane. • Slide off the nut cover. • Unscrew and remove the wheel axle fixing nut and collect the washer.
  • Page 208 RS4 125 Suspensions • Check the wheel axle by turning the wheel rim on a flat surface. • If there are bends, replace it. WARNING NEVER TRY TO STRAIGHTEN THE BEND AXLE. Wheel axle bending limit (1): 0.2 mm TYRES •...

  • Page 209: Installing The Front Wheel

    RS4 125 Suspensions • Check wheel bearings. NOTE BEARINGS MUST ROTATE FREELY, WITHOUT JAMMING AND/OR NOISE, OTHERWISE, THEY NEED TO BE RE- PLACED. • Check the spacer. • Replace together with the retaining ring if there are scorings or signs of de- terioration.

  • Page 210: Front Fork

    RS4 125 Suspensions Handlebar ANDLEBAR AND ONTROLS pos. Description Type Quantity Torque Notes Semi-handlebar retainer M8x30 25 Nm (18.44 lbf ft) Loctite 243 Handlebar counterweight retainer M5x50 5 Nm (3.69 lbf ft) Loctite 243 Front fork Removing the fork legs The following operations are described for the Mingxing fork, but are identical for the operation with the fork model Paioli, except where specified.
  • Page 211 RS4 125 Suspensions • Loosen the fixing screw at the upper steering plate. See also Rear mudguard Removing the front wheel • For the operation with Mingxing fork, loosen the two fixing screw at the lower plate. • For the operation with fork Paioli, loos- en the fixing screw at the lower plate.
  • Page 212 RS4 125 Suspensions • Undo the cap and partially pull out the piston • Using a wrench to prevent the internal piston from rotating • Remove the cap CAUTION BEFORE PROCEEDING WITH THE FOLLOWING OPERATIONS GET A SUITABLE COLLECTION CONTAINER.
  • Page 213 RS4 125 Suspensions • Reposition the stem in the vice using the specific Teflon shoes. • Remove the dust gaiter, taking care for the surface of the stem and the integrity of the dust gaiter. • Remove the retainer ring.
  • Page 214 RS4 125 Suspensions • Remove the complete piston MINGXING FORK CAUTION THE FOLLOWING PROCEDURES ARE FOR A SINGLE WHEEL CARRIER STANCHION/SLEEVE ASSEMBLY, BUT ARE APPLICABLE TO BOTH. • Fit the fork in the vice using the special Teflon grips. •...
  • Page 215 RS4 125 Suspensions • Remove the internal piston and, lower- ing the lock washer, remove the two half cylinders • Remove the lock washer CAUTION BEFORE PROCEEDING WITH THE FOLLOWING OPERATIONS GET A SUITABLE COLLECTION CONTAINER. • Remove the stem from the vice and drain off the oil inside it into the collec- tion container.
  • Page 216 RS4 125 Suspensions • Remove the stem from the sleeve. CAUTION BE CAREFUL NOT TO DAMAGE THE SLEEVE INTERIOR WHEN REMOVING THE DIFFERENT COMPONENTS. • Remove the oil seal from the sleeve, taking care not to damage it Checking the components...
  • Page 217 RS4 125 Suspensions - O-ring gasket on the cap. • Check that there are no damages and/ or cracks; otherwise, replace it. • Check that the sliding bushings (1) for good conditions. • If there are signs of excessive wear or damage, replace the affected compo- nent.
  • Page 218 RS4 125 Suspensions Reassembling the fork PAIOLI FORKS CAUTION ONLY FOR THE RIGHT STEM IT IS POSSIBLE TO INSTALL THE COMPLETE PISTON OPERATING AS FOLLOWS • Tighten the piston retaining screw on the foot of the fork and tighten it to the...
  • Page 219 RS4 125 Suspensions • After inserting the dust gaiter in the stem as well as the retainer ring, insert the stem itself in the sleeve • Position the retainer and push the dust gaiter into its seat • Position the fork vertically in a vice •...
  • Page 220 RS4 125 Suspensions • Screw the cap on the sleeve MINGXING FORK CAUTION THE FOLLOWING PROCEDURES ARE FOR A SINGLE WHEEL CARRIER STANCHION/SLEEVE ASSEMBLY, BUT ARE APPLICABLE TO BOTH. • Insert the oil seal in the sleeve • After inserting the dust gaiter in the...

  • Page 221: Installing The Fork Legs

    RS4 125 Suspensions • Insert the retainer ring • Position the two half cylinders and lock them in place with the retainer ring • Position the fork vertically in a vice • Fill the fork with oil Characteristic Fork MingXing oil quantity Right stem: 355+/-5 ml (0.0781+/-0.0011 UK gal;...
  • Page 222 RS4 125 Suspensions • Insert the sleeve together with the wheel holder stem on the lower and upper plates. • Insert the wheel pin through both stems to align the holes. • Insert the stems holding pipe on the lower plate, in the clamps of the front headlamp and on the upper plate.
  • Page 223 RS4 125 Suspensions • Tighten the screw that tightens the up- per plate to the sleeve. • Tighten the two screws on the front headlamp clamp. • Fasten the brake piping to the left sheath. • Slide off the wheel axle.
  • Page 224 RS4 125 Suspensions • Lower the hoist arm. CAUTION BEFORE RELEASING THE BELTS MAKE SURE THAT THE OPTIONAL REAR SERVICE STAND IS ADEQUATELY POSITIONED. • Correctly fit the lower shield, the mudguard, the front wheel, the brake callipers. • Release the belts from the chassis.

  • Page 225: Removing The Rear Wheel

    RS4 125 Suspensions 9. Circlip d47 10.Bare rear wheel blue 11.Sprocket carrier 12.Bearing 25x47x14 13.Sealing ring 30x47x7 14.Int. spacer 15.Anti-vibration rubber buffer 16.Master link 17.Rear brake disc 18.TSPEI screw m8x20 19.Crown z=40 20.TE flanged screw m10x30 EAR WHEEL pos. Description...
  • Page 226 RS4 125 Suspensions UPON REMOVING, PAY ATTENTION NOT TO DAMAGE THE BRAKE HOSES, DISCS AND PADS. CAUTION TO REMOVE THE REAR WHEEL, GET THE APPROPRIATE REAR SERVICE STAND (OPTIONAL). • Place the vehicle on its optional rear stand. • Remove the drive chain.

  • Page 227: Checking The Rear Wheel

    RS4 125 Suspensions • Slide the rear wheel completely off and check the mechanical components. Checking the rear wheel CAUTION CHECK THAT ALL PARTS ARE IN GOOD CONDITION, ES- PECIALLY THOSE LISTED AS FOLLOWS. BEARINGS, GASKETS, WHEEL PIN, RIM. FLEXIBLE COUPLING Check that the anti-vibration buffer is not damaged and/or excessively worn.

  • Page 228: Installing The Rear Wheel

    RS4 125 Suspensions Installing the rear wheel • Follow the removal steps but in reverse order, be careful to adequately position the spacers on the left side as indicated in the figure. • Tighten the nuts to the prescribed tor- que.
  • Page 229 RS4 125 Suspensions Removing • Remove both central side fairings. • Place the vehicle on its optional front service stand. • Support the vehicle rear part using belts and hoist. • Place a support under the swingarm, so that it stays in neutral position.
  • Page 230 INDEX OF TOPICS CHAS HASSIS...
  • Page 231 RS4 125 Chassis CHASSIS pos. Description Type Quantity Torque Notes Support coil fixing screw 20 Nm (14.75 lbf ft) TCEI screw 25 Nm (18.43 lbf ft) TCEI screw M10x45 50 Nm (36.88 lbf ft) TE screw M8x40 25 Nm (18.43 lbf ft)
  • Page 232 RS4 125 Chassis Swinging arm WINGARM pos. Description Type Quantity Torque Notes Swingarm to chassis adjustment nut M25x1.5 15 Nm (11.06 lbf ft) Swingarm pin nut 78 Nm (57.52 lbf ft) Chainguard fixing screw M 4.8x13 1 Nm (0.74 lbf ft) Chainguard fixing screw Self-tap.
  • Page 233 RS4 125 Chassis • Operating on both sides, loosen the swingarm pin tightening nut. • Working on the left side, unscrew and remove the nut and collect the washer. See also Removing the rear wheel • Working from the right side of the ve- hicle, unscrew and remove the nut and retrieve the washer.
  • Page 234 RS4 125 Chassis SWINGARM PIN With a dial gauge check if the pin eccentricity ex- ceeds the limit value. Otherwise, replace the pin. Maximum pin eccentricity: 0.3 mm (0.01 in) Installing • To install the swingarm follow the operations described for removal in reverse order, being careful to tighten the ring nuts, nuts and screws to the prescribed torque.
  • Page 235 RS4 125 Chassis Removing • Remove the pinion cover crankcase. • Increase the chain clearance to allow removal of the pinion OPTION 01 • Remove fixing screws of the pinion lock plate • Rotate the pinion lock plate to remove it the from the shaft.
  • Page 236 RS4 125 Chassis • Unscrew and remove the pinion lock • Remove the Belleville spring • Remove the pinion Installing OPTION 01 • Insert the pinion on the shaft. CHAS - 236...
  • Page 237 RS4 125 Chassis • Insert the pin retainer plate and rotate it to match the holes. • Insert the fixing screws of the pinion and tighten them to the prescribed tor- que. OPTION 02 • Insert the pinion on the shaft.

  • Page 238: Drive Chain

    RS4 125 Chassis • Place the nut and tighten it to prescri- bed torque • Insert the pinion cover crankcase. • Tension the chain so that there is a correct clearance See also Adjusting Drive chain Removing • Support the vehicle with the optional rear stand.
  • Page 239 RS4 125 Chassis IF THE CHAIN ROLLERS ARE DAMAGED AND / OR THE PINS ARE LOOSE, THE ENTIRE CHAIN UNIT (PINION, CROWN AND CHAIN) SHOULD BE REPLACED. LUBRICATE THE CHAIN ON A REGULAR BASIS, PARTICULARLY IF YOU DETECT DRY OR RUSTY PARTS.
  • Page 240 RS4 125 Chassis IF CLEARANCE IS GREATER AT SOME POSITIONS, THIS MEANS THAT SOME CHAIN LINKS ARE FLATTENED OR JAMMED. TO AVOID RISK OF SEIZURE, LUBRICATE THE CHAIN ON A REGULAR BASIS. CAUTION GET A SPECIFIC REAR SERVICE STAND (OPT) TO AD- JUST THE CHAIN.

  • Page 241: Chain Tensioner

    RS4 125 Chassis Chain tensioner TAND pos. Description Type Quantity Torque Notes Thin nut M10x1.25 10 Nm (7.38 lb ft) TCEI screw M8x30 25 Nm (18.43 lb ft) Loctite 243 TCEI screw M8x45 25 Nm (18.43 lb ft) TE Screws Flang.
  • Page 242 RS4 125 Chassis • In case replacing the roller bearings only, be careful to retrieve the spacer between the two. • Remove the screw and the relative re- tainer nut of the chain tensioner plate. • If necessary, replace the spring.

  • Page 243: Side Stand

    RS4 125 Chassis • Insert the screw with related washer and the special nut to secure the chain tensioner plate paying attention to cor- rect positioning of the spring. • Fit the roller on the chain tensioner plater after having assembled it complete with bearings and spacer.
  • Page 244 RS4 125 Chassis Exhaust XHAUST pos. Description Type Quantity Torque Notes Drainage retainer M6x20 10 Nm (7.37 lbf ft) Footrest retainer M8x40 25 Nm (18.43 lbf ft) Removing the tail pipe • Undo and remove the two upper stay- screws and collect the relative nuts and washers.
  • Page 245 RS4 125 Chassis • Beforehand, remove the side fairings and the fairing lug. • Loosen the clamp. See also Side fairings • Remove the exhaust end. CHAS - 245...
  • Page 246 RS4 125 Chassis Removing the exhaust manifold • Unscrew and remove the two screws. • Remove the manifold. • Remove the muffler. • Lift the saddle and disconnect the lambda probe connector. See also Removing the tail pipe CHAS - 246...
  • Page 247 INDEX OF TOPICS BRAK SYS RAKING SYSTEM...
  • Page 248 RS4 125 Braking system RONT BRAKE PUMP pos. Description Type Quantity Torque Notes Front brake pump fixing screw 5 Nm (3.68 lbf ft) Brake pipe clamp fixing screw M5x16 5 Nm (3.68 lbf ft) RONT ALLIPER pos. Description Type Quantity...
  • Page 249 RS4 125 Braking system RAKING YSTEM pos. Description Type Quantity Torque Notes Brake lever fixing screw M6x40 12 Nm (8.85 lbf ft) Rear brake pump fixing screw M6x30 10 Nm (7.37 lbf ft) Brake pump joint retainer 10 Nm (7.37 lbf ft)
  • Page 250 RS4 125 Braking system Removal • Release the chain. • Loosen the wheel axle, acting on the nut, from the right side of the vehicle and on the pin, from the left side. • Move the rear wheel. • Move the rear brake calliper plate until the end and slide it one off.
  • Page 251 RS4 125 Braking system Installing • Place the complete calliper on the spe- cific lodging on the swingarm. • Connect the drive chain after position- ing the wheel and insert the retaining • Insert the washer, the nut and fix the pin at the prescribed torque •...
  • Page 252 RS4 125 Braking system • Unscrew and remove both calliper fixing screws (2). • Slide off the front brake calliper. See also Bleeding the braking system Rear brake disc Removal • Remove the wheel. • Unscrew and remove the six disc fixing screws.
  • Page 253 RS4 125 Braking system • Check the decentralisation with a mi- crometer by placing it on the disc (A) and turning the wheel. • If the decentralisation exceeds the serviceability limit, replace the disc. Decentralisation of the disc: 0.2 mm...

  • Page 254: Front Brake Pads

    RS4 125 Braking system • Check the decentralisation with a mi- crometer by placing it on the disc (A) and turning the wheel. • If the decentralisation exceeds the serviceability limit, replace the disc. Decentralisation of the disc: 0.2 mm...
  • Page 255 RS4 125 Braking system • On the front brake calliper on the left hand side of the vehicle, undo and remove the two brake calliper fastener screws. • Remove the circlip. • Remove the pad fastener pin. • Remove the pads.

  • Page 256: Rear Brake Pads

    RS4 125 Braking system • Measure the thickness of the brake pads. If one of the two falls under the serviceability limit, replace them. Serviceability limit 1.5 mm (0.05 in). WARNING IF THE BRAKE LEVER STARTS WITHOUT THE CALLIPER IT MAY BE NECESSARY TO CARRY OUT THE CORRESPONDING BLEEDING.
  • Page 257 RS4 125 Braking system Bleeding the braking system NOTE IF AIR CONTINUES TO COME OUT DURING THE BLEED OPERATION EXAMINE ALL THE FIT- TINGS: IF SAID FITTINGS DO NOT SHOW SIGNS OF BEING FAULTY, LOOK FOR THE AIR INPUT AMONG THE VARIOUS SEALS ON THE PUMP AND CALLIPER PISTONS.
  • Page 258 RS4 125 Braking system OF BRAKE FLUID. CHECK THAT, DURING THE OPERATION, THERE IS ALWAYS BRAKE FLUID IN THE RESERVOIR. • Remove the rubber protection cover from the bleed valve. • Insert the transparent plastic pipe in the front brake calliper bleed valve and slide the other end of this pipe in a container to collect the fluid.

  • Page 259: Changing The Brake Fluid

    RS4 125 Braking system • Insert the transparent plastic pipe in the rear brake calliper bleed valve and insert the other end of this pipe into a container to collect the fluid. • Remove the rear brake fluid reservoir cap.
  • Page 260 RS4 125 Braking system IF THE BRAKE LEVER STARTS WITHOUT THE CALLIPER IT MAY BE NECESSARY TO CARRY OUT THE CORRE- SPONDING BLEEDING. Front brake pump • Unscrew and remove the screw and, by disconnecting the hoses, collect the brake oil in the tank, in an adequate container.
  • Page 261 RS4 125 Braking system Rimozione • Unscrew the screw, disconnect the pipe, collect the break fluid in an ade- quate container. • Unscrew and remove the two screws and collect the corresponding nuts. • Unscrew and remove the nut, retriev- ing the nut.
  • Page 262 INDEX OF TOPICS COOL SYS OOLING SYSTEM...
  • Page 263 RS4 125 Cooling system ADIATOR pos. Description Type Quantity Torque Notes Radiator retainer M6x25 10 Nm (7.37 lbf ft) Expansion tank support fixing screw M6x20 3.5-4 Nm (2.58-2.95 lbf COOL SYS - 263...

  • Page 264: Circuit Diagram

    RS4 125 Cooling system ATER PUMP pos. Description Type Quantity Torque Notes Water pump fixing screw 5 - 6 Nm (3.68 - 4.42 lbf Circuit diagram key: 1. Breather pipe 2. Radiator - expansion tank pipe 3. Cooling liquid reservoir 4.

  • Page 265: Coolant Replacement

    RS4 125 Cooling system 16.Cable grommet rubber ring 17.Pump-radiator pipe 18.Head-radiator pipe 19.Electric fan 20.Washer 21.Pin 22.Washer 23.Screw 24.Screw Electric fan • Remove the radiator • Undo and remove the three screws and collect the washers; remove the electric fan.

  • Page 266: Water Pump

    RS4 125 Cooling system Side fairings • Release the clamp. Slide the pipe off and let the cooling liquid spill out, by pouring it into a container of a suitable capacity. CAUTION DO NOT DISPOSE OF THE FLUID INTO THE ENVIRON- MENT.
  • Page 267 RS4 125 Cooling system • Remove the clutch cover; • Heat the clutch cover to facilitate extraction of the water pump spindle assembly; • Support the clutch cover on a press and with the specific tool "B", remove the water pump shaft group, acting from the external part to the internal one.
  • Page 268 RS4 125 Cooling system ALWAYS REPLACE THE BEARINGS, THE OIL SEAL, AND THE SEALING RING, WHENEVER IT IS NECESSARY TO REMOVE THE WATER PUMP. • Place the new bearings on the press and with the specific tool "B" push the shaft until it stops;...
  • Page 269 RS4 125 Cooling system • Place the gear paying attention that the operation is oriented to the cover; • Use the specific tool "B" as an endstop in order to push the gear, with the press, until it is in line with the shaft.
  • Page 270 RS4 125 Cooling system • Lift the fuel tank and disconnect the electric fan connector. See also Removing the expansion tank • Unscrew the radiator cover and let it connect to the hoses. • Loosen the clamp with a screwdriver.
  • Page 271 RS4 125 Cooling system • Sliding it off the fitting slots, remove the radiator. • Remove the electric fan if necessary. Radiator installation • Install the radiator following the removal operations but in reverse order. • Fill the coolant tank with the recommended product.
  • Page 272 RS4 125 Cooling system • Loosen the clamp and slide off the ho- ses. See also Side fairings Coolant replacement • Unscrew and remove the tank fixing screw. • Slide off the coolant tank. INSTALLATION • For the installation, proceed in reverse...
  • Page 273 INDEX OF TOPICS BODYW ODYWORK...
  • Page 274 RS4 125 Bodywork pos. Description Type Quantity Torque Notes Rear tank fixing screw M8x40 25 Nm (18.44 lbf ft) Front tank fixing screw M6x35 10 Nm (7.37 lbf ft) Fastener screw M5x9 3 Nm (2.21 lbf ft) Tank cover fixing screw M5x9 3 Nm (2.21 lbf ft)

  • Page 275: Instrument Panel

    RS4 125 Bodywork Driving mirrors • Unscrew and remove the two nuts in- side the top fairing, two for each mirror. • Remove the rear-view mirrors. Instrument panel • Remove the windshield. • Lift the instrument panel and discon- nect the connector.
  • Page 276 RS4 125 Bodywork INSTRUMENT PANEL SUPPORT REMOVAL • Unscrew and remove the two stay- bolts and retrieve the washer from the left side and the nut from the right side. • Unscrew and remove the six perimeter screws and remove the two shells.
  • Page 277 RS4 125 Bodywork pos. Description Type Quantity Torque Notes Turn indicator fixing screw 1.5 Nm (1.11 lbf ft) • Remove the top fairing. • Disconnect the two bulb connectors. • Operating from both sides, disconnect the connectors from the turn indicators.
  • Page 278 RS4 125 Bodywork • Remove the two side screws fixing the top fairing to the chassis. • Unscrew and remove the two top fair- ing side screws. • Unscrew and remove the two screws on the front fairing. • Disconnect the instrument panel con- nector.
  • Page 279 RS4 125 Bodywork • Remove the windshield. Front wheelhouse • Remove the fairing from the side of the wheel housing that you want to re- move. • Operating from the left shield, unscrew and remove the regulator fixing screw, collecting the nut and the washer.
  • Page 280 RS4 125 Bodywork Taillight assy. • Remove the tail fairing and the pas- senger saddle. • Remove the two side screws (1). • Remove the two upper screws (2). • Disconnect the connector. See also Tail guard • Take off the rear light unit, by removing it from the hooks.
  • Page 281 RS4 125 Bodywork Footrest PASSENGER FOOTREST The following procedures only refer to one foot- rest, but they are applicable to both. • Remove the tail fairing. • Unscrew and remove the two fixing screws. • Remove the passenger footrest. See also...
  • Page 282 RS4 125 Bodywork License plate holder • Remove the passenger saddle. • Remove the lower licence plate sup- port cover. • Unscrew and remove the central lower screw. • Unscrew and remove the two lower screws. • Remove the three clamps.
  • Page 283 RS4 125 Bodywork • Disconnect the connector. • Remove the license plate support. Air box • Remove the passenger footrest, the saddle, the tank, the fairing and the splash guard. • Unscrew and remove the four screws (1). • Loosen the clamp and remove the in- take tube.
  • Page 284 RS4 125 Bodywork • Remove the air filter box. Rear mudguard • Unscrew and remove the screw. • Slide off the pipe grommet. • Operating from the right side, unscrew and remove the central screw. • Working on the left side, unscrew and remove the two screws.
  • Page 285 RS4 125 Bodywork Lower cowl • Remove the side fairings. • Position the vehicle on the optional rear stand, with the vehicle on the open side stand. • Remove the side rivet. • Carry out the following operations on one side of the vehicle and then on the other.

  • Page 286: Fuel Tank

    RS4 125 Bodywork • Remove the lower rivet. • Slide the right semi-lug off from the right side. • Slide off the left semi-lug from the left side, along the stand profile. Fuel tank • Remove the rider saddle. •...
  • Page 287 RS4 125 Bodywork Central part • Slide off the fuel breather pipe. • Operating from both sides, unscrew and remove the screw and collect the nut on the internal side. • Keeping the tank in position, lower it by removing the supporting rod.
  • Page 288 RS4 125 Bodywork Radiator cover • Unscrew and remove the central screw. • Unscrew and remove the two upper screws. • Retrieve the corresponding washers. • Unscrew and remove the two lower screws. • Slide off the radiator cover. •...
  • Page 289 RS4 125 Bodywork Tail guard • The following procedures refer to the left side of the vehicle, but apply to both. • Remove the central side fairing and the passenger saddle. • Unscrew and remove the two front screws and the rear screw.
  • Page 290 INDEX OF TOPICS PRE DE DELIVERY...
  • Page 291 RS4 125 Pre-delivery Carry out the listed checks before delivering the motorcycle. WARNING HANDLE FUEL WITH CARE. Carry out the listed checks before delivering the motorcycle. WARNING HANDLE FUEL WITH CARE. Aesthetic inspection - Paintwork - Fitting of Plastic Parts...
  • Page 292 RS4 125 Pre-delivery - Horn - Electric starter - Engine stop via emergency stop switch and side stand - Helmet compartment electrical opening switch (if present) - Through the diagnosis tool, check that the last mapping version is present in the control unit/s and, if required, program the control unit/s again: consult the technical service website to know about available upgrades and details regarding the operation.

  • Page 293: Road Test

    RS4 125 Pre-delivery - Mixer oil level (if present) Road test - Cold start - Instrument panel operation - Response to throttle control - Stability when accelerating and braking - Front and rear brake efficiency - Front and rear suspension efficiency...
  • Page 294 RS4 125 Pre-delivery CHECK AND ADJUST TYRE PRESSURE WITH TYRES AT AMBIENT TEMPERATURE. Specific operations for the vehicle To fit the Quick Shift, follow these assembling in- structions. • Remove the gear tie rod by unscrewing the two fixing screws.
  • Page 295 RS4 125 Pre-delivery • Access the Quick Shift connector by lifting the tank, the connector is placed, as shown in the figure, internally on the left side of the chassis. • Connect the two cables. PRE DE - 295...
  • Page 296 Air filter: 55 Battery: 98, 108 Brake: 249, 251–254, 256, 259, 260 Brake calliper: 249, 251 Brake disc: 252, 253 Brake fluid: 259 Brake pads: 254, 256 Brake pump: 260 Bulbs: Chain: 184, 226, 238, 241 Chain tensioner: 184, 241 Clutch: 62, 148, 149, 151, 153–155, 159 Coil: 120 Connectors: 123...
  • Page 297 Handlebar: 210 Head cover: 172 Headlight: 275–277 Horn: 105 Identification: 9 Instrument panel: 275 License plate holder: 282 Magneto flywheel: 145, 147, 162 Maintenance: 7, 50 Mirrors: 275 Mudguard: 211, 284 Oil filter: 54 Primary shaft: 140 Radiator: 127, 265, 269, 288 Rear wheel: 225, 227, 228, 233 Recommended products: 43 Scheduled maintenance:...
  • Page 298 Windshield: Wiring diagram: 92...

Table of Contents