Derbi GP1 50 cc Workshop Manual
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Derbi GP1 50 cc Workshop Manual

Derbi GP1 50 cc Workshop Manual

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ORKSHOP MANUAL
GP1 50 cc

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  • Page 1 ORKSHOP MANUAL GP1 50 cc...
  • Page 2 The intention is to provide as much assistance as possible to mechanics working for our brand’s dealers and sub-dealers. Due to its constant commitment to improving its products, DERBI - NACIONAL MOTOR, S.A. Sociedad Unipersonal reserves the right to introduce any modifications it deems fit, without prior warning.
  • Page 4 Page 1 INTRODUCTION Page 8 GENERAL INFORMATION Page 9 GENERAL TECHNICAL DATA Page 18 RECOMMENDED TOOLS Page 24 REGULAR MAINTENANCE DISMANTLING Page 35 SEAT SIDE TRIM Page 35 COWLING Page 36 COWLING BOTTOM COVER Page 36 WATER-OIL TANK COVER Page 36 SIDE COVERS Page 37 SHIELD BOTTOM COVER...
  • Page 5 Page 49 ASSEMBLING CLUTCH Page 50 FITTING DRIVEN PULLEY Page 50 TRANSMISSION BELT Page 51 DISMANTLING DRIVING PULLEY Page 51 MIXER GEARING AND BELT Page 51 CHECKING ROLLER CONTAINER Page 52 FITTING DRIVING PULLEY FINAL REDUCTION Page 53 DISMANTLING ENGINE PINION Page 53 DISMANTLING HUB COVER Page 54...
  • Page 6 Page 63 CHECKING THE OIL SEALS Page 63 FITTING THE PISTON Page 64 CHECKING TIMING COMPONENTS CRANKCASE Page 65 OPENING THE CRANKCASE Page 65 DISMANTLING THE CRANKSHAFT Page 65 DISMANTLING THE MAIN BEARINGS Page 66 FITTING THE MAIN BEARINGS Page 67 CHECKING THE CRANKSHAFT ALIGNMENT Page 67 FITTING THE CRANKSHAFT...
  • Page 7 REAR WHEEL AND BRAKES Page 91 REAR WHEEL DIAGRAM Page 92 DISMANTLING Page 92 DISMANTLING THE REAR DISK CALLIPER Page 99 INSPECTING THE REAR WHEEL Page 99 REFITTING THE REAR WHEEL TRANSMISSION Page 100 DISMANTLING Page 101 INSPECTING THE TRANSMISSION CHAIN Page 101 CROWN WHEEL Page 102...
  • Page 8 Page 118 CHECKING THE STATOR Page 118 CHECKING THE VOLTAGE REGULATOR Page 119 OPERATIONS Page 122 FUSES Page 122 DISMANTLING THE BATTERY Page 124 BATTERY-INITIAL CHARGE Page 124 CAPACITY Page 125 INSPECTING THE CHARGING CONDITIONS Page 126 RECHARGING Page 127 CHECKING THE ELECTRICAL SYSTEM TROUBLESHOOTING Page 128...
  • Page 9 MAINTENANCE REGULATIONS MAINTENANCE REGULATIONS - Use genuine DERBI spare parts and lubricants recommended by the manufacturer. Non-genuine or unau- thorised parts may damage the engine. Always use new gaskets and oil seals during re-assembly.
  • Page 10 MACHINE ENGINE PREFIX FRAME PREFIX GP1 50 c.c. GP1 50 c.c. C451M VTHPR1A1A IMENSIONS AND WEIGHT CHARACTERISTIC DIMENSION/VALUE Maximum length 1875 mm. Maximum height 1212 mm. Length between axles 1338 mm. Handlebar width 705 mm. Handlebar height 1050 mm. Total weight of machine 117 kg.
  • Page 11 NGINE CHARACTERISTIC DIMENSION/VALUE Alimentación Depression fuel pump supplying lead free petrol via the carburettor. Sistema de refrigeración By forced circulation of liquid. Embrague Dry automatic centrifugal Piñón salida cambio Z 19 Plato de arrastre Z 45 RANSMISSION CHARACTERISTIC DIMENSION/VALUE Automatic speed variator with expandable pulleys, tra- Transmission pezoidal belt, automatic clutch, gear reducer.
  • Page 12 RAME AND SUSPENSIONS CHARACTERISTIC DIMENSION/VALUE Frame Aluminium, Delta Box type Front suspension Telescopic forks with inverted bars Diameter / Travel 35 mm / 80 mm Oil capacity 95 c.c. Oil type SAE 7,5 W Rear suspension Swinging arm with single shock absorber. Travel 80 mm RAKING SYSTEM...
  • Page 13 ARBURETTOR CHARACTERISTIC DIMENSION/VALUE Emulsifier 209HA Idle jet Minimum air jet Libre Secondary minimum air orifice Ø 2.5 mm Minimum mixture screw initial opening 1 1/2 Choke jet Choke air jet Ø 1.5 mm Choke needle travel 11 mm Fuel entry orifice Ø...
  • Page 14 HASSIS TIGHTENING TORQUES DESCRIPTION TORQUES (N.M) TORQUES (M.KG) SEALER Top shock absorber - chassis securing device M10x150 8.8 30 ÷ 40 3 ÷ 4 Bottom shock absorber – engine securing device M10x150 8.8 30 ÷ 40 3 ÷ 4 Engine Silent bloc – chassis securing device M10x150 8.8 30 ÷...
  • Page 15 NGINE TIGHTENING TORQUES DESCRIPTION TORQUES (N.M) TORQUES (M.KG) Clutch bell housing nut 40 ÷ 44 4 ÷ 4.4 Clutch locking nut 55 ÷ 60 5.5 ÷ 6 Nut for locking the driving pulley on the crankshaft 40 ÷ 44 4 ÷ 4.4 Kick start lever bolt 12 ÷...
  • Page 16 ONECTION PISTON AND CYLINDER NAME PLAY INITIALS CYLINDER PISTON PLAY ON FITTING Standard fitting <⁄> 39,997-40,004 39,943-39,95 0,047-0,061 Standard fitting <⁄> 40,004-40,011 39,95-39,957 0,047-0,061 Standard fitting <⁄> 40,011-40,018 39,957-39,964 0,047-0,061 Standard fitting <⁄> 40,018-40,025 39,964-39,971 0,047-0,061 1st oversize fitting <⁄> 40,197-40,204 40,143-40,15 0,047-0,061...
  • Page 17 ND PLAY BETWEEN CRANKCASE CRANKSHAFT AND CONNECTING ROD NAME DESCRIPTION DIMENSIONS INITIAL QUANTITY Play E=0,25÷0,50 Connecting rod Connecting rod 11,750 ÷ 0,05 Play F= 2,20÷0,75 Play E=0,25÷0,50 Packing washer Packing washer 0,5 ÷ 0,03 Play F= 2,20÷0,75 Play E=0,25÷0,50 Half shaft transmission side Half shaft transmission side 13,75 ÷...
  • Page 18 ISTEMA DE MONTAJE DE ESPESORES NAME MEASURE A THICKNESS Packing 2,80 ÷ 3,04 Packing 3,04 ÷ 3,24 Spacing 3,24 ÷ 3,48...
  • Page 19 PREPARATION FOR REMOVAL AND DISMANTLING PREPARATION FOR REMOVAL AND DISMANTLING 1. Remove all the dirt, grime, dust and other foreign material before removing and dismantling. 2. Use properly cleaned tools and equipment. See “SPECIAL TOOLS”. 3. On dismantling the motorcycle, always keep paired parts together.
  • Page 20 EPLACEMENT PARTS 1. Use only genuine DERBI spare parts. For all lubrication tasks use oils and greases recommended by DERBI. Other makes make seem similar in their function and appearance, but are inferior in quality. EALS EALS RETAINING RINGS AND O...
  • Page 21 OCKING RINGS 1. Examine all the locking rings carefully before fitting. Always replace the gudgeon pin circlips after every use. Re- place distorted locking rings. On fitting a locking ring (1), ensure that the sharp edge (2) is on the opposite side to the force to be applied to it.
  • Page 22 STORES CODE DESCRIPTION IMAGE 020151Y Air heater Flywheel extractor 020162Y 020163Y Crankc splitting plate 020164Y Half-pulleys fixing sheath 020451Y Starter sprocket retainer Piston rings fixing tool 020166Y 020163Y Bearing fitting stand 020167Y Impeller retaining spanner...
  • Page 23 REFERENCIA DESCRIPCIÓN IMAGEN 020168Y Oil seal fitting drift on half crankcase 020169Y Water pump drive shaft spanner 020170Y Extractor engagement sends mixer 020325Y Pliers for brake-shoe springs 020331Y Digital multimeter 020332Y Digital rpm counter 020334Y Multiple battery charger 020335Y Magnetic stand and comparator...
  • Page 24 REFERENCIA DESCRIPCIÓN IMAGEN 020350Y Electric system diagnostic device 020656Y Compass flywheel stop spanner 020340Y Crankshaft sela punch 020080Y Needle bearing punch Crankcase-half water-seal 020168Y assembly punch 020341Y Piston ring assembly tool 020342Y Compressor crankshaft pulley retaiting tool 00G05300131 Change output pinion tool...
  • Page 25 AINTENANCE CHART BEFORE EVERY START-UP ACTION Check the oil level Check the brake fluid level Check the coolant level Check wear on brake pads/shoes Check light mechanism operation Check horn operation Check chain tension Check tyre pressure and wear Check for possible fluid leaks (petrol, oil, coolant, brake fluid) Check for possible cracks in the fuel pipes Check that all the control elements are operating correctly Check that the brakes are operating correctly...
  • Page 26 AT 1000 KM OR 4 MONTHS ACTION Hub oil - Replacement Oil mixter / Throttle linkage - Adjust Speedometer cable - Grease Steering - Adjust Brake levers - Grease Brake fluid level - Check Nuts, bolts and fasteners - Check Electrical system and battery - Check Tires-inflation and wear - Check Vehicle and brake test - Road test...
  • Page 27 AT 10000 KM OR 24 MONTHS AND 50000 KM ACTION Hub oil - Replacement Spark plug / spark gap - Replacement Air filter - Cleaning Idle speed / Fuel - Adjust Oil mixer / Throttle linkage - Adjust Variators rollers - Change Speedometer cable - Grease Transmition Belt - Check Cooling fluid level - Check...
  • Page 28 AT 20000 KM AND 40000 KM ACTION Hub oil - Replacement Spark plug / electrode gao - Change Air filter - Cleaning Idle speed / Fuel - Adjust Cylinder cooling system - Check / Clean Oil mixer / throttle linkage- Adjust Transmission Belt - Check Variatos roller - Change Fuel-oil mixer belt - Change...
  • Page 29 AT 30000 KM ACTION Braking circuit hose - Replacement Brake fluid level - Check Transmisions - Lubricate Buts, bolts and fasteners - Check Suspensions - Check Electrical system and battery - Check Headlight - Adjust Tires-inflation and wear - Check SAS box (esponge) - Clean Vehicle and brake test -Road test AT 60000 KM...
  • Page 30 PARK PLUG PARK PLUG - Rest the vehicle on its centre-stand; - Detach the spark plug flap by removing the two fixing screws; - Detach the H.T. cable cap from the spark plug; - Remove the spark plug using the box-spanner provided; - Examine the conditions of spark plug, the integrity of the insulator, and measure the spark gap with the aid of a feeler gauge.
  • Page 31 UB OIL UB OIL Check To check the level, proceed as follows: 1) Rest the vehicle onto its centre-stand, on flat ground; 2) Remove dipstick «A»; dry it with a clean cloth and reinsert it, using the whole thread; 3) Remove the dipstick and check the oil mark reaches just below the second notch from the bottom;...
  • Page 32 IR FILTER IR FILTER - Remove the cleaner plug by unloosing the 6 fixing screws. Remove the filtering element. Cleaning: -Wash with water and neutral soap. -Dry with a clean cloth and small jets of compressed air. -Soak with a 50 fuel/oil mixture. -Let the filtering element drain and then squeeze it with your hands without crushing it.
  • Page 33 HECKING THE IGNITION TIMING HECKING THE IGNITION TIMING Adjust the control cables: Mixer cable: see “Mixer timing” procedure, below. Throttle cable: Adjust the screw on the carburettor so that there is no play on the sheath. Splitter control cable: Adjust the screw on the throttle grip on the handlebar so that there is no play on the twist grip.
  • Page 34 RAKING SYSTEM RAKING SYSTEM Level check Proceed as follows: - Rest the vehicle onto its centre-stand and align the han- dlebars; - Check the liquid level through the inspection hole «A». A certain decrease in the liquid level is due to the wear of the pads.
  • Page 35 EADLIGHT ADJUSTMENT EADLIGHT ADJUSTMENT Proceed as follows: 1. Position the vehicle in riding conditions, and with the tyres inflated at the prescribed pressure, on a horizontal surface 10m away from a half-lit white screen, ensuring the vertical axis of the vehicle is perpendicular to the screen; 2.
  • Page 36 1. SEAT SIDE TRIM • Extract the 3 securing screws (2 Philips 3.6x14 self- tappers and one 5x16 Allen M3) from each cover. Time taken: 4 Minutes 2. COWLING • Extract the 6 screws (5x12 Allen M3) from under the cowling.
  • Page 37 3. LOWER COWLING COVER • Extract the 2 securing screws (Philips 6x16 with was- her) Time taken: 17 Minutes N.B. TO CONTINUE WITH THE HELMET HOLDER WE NEED TO CONTINUE DISMANTLING THE FRONT PART, SIN- CE THE PETROL TANK FRONT BREATHER PIPE PASSES THROUGH THE HELMET HOLDER.
  • Page 38 6. SHIELD INNER COVER • Extract the 2 screws (5x12 Allen M3). • Extract the 3 top screws (2 Philips 3.6x14 self-tappers and one6x16 Allen screw with washer). Time taken: 23 Minutes 7. PETROL TANK COVER • Extract the bottom covers (left and right), by remo- ving the 6 screws (Philips 5x16 with washer) and the two air inputs, 3 screws (1 Philips 3x10 self-tapper, 1 Philips 3.6x10 self-tapper and 1 Philips 5x16), as there are 2...
  • Page 39 • After extracting the 6 side screws and the central one (Allen M3 5x12) from the tank cover, lift the front of this removing the 2 lugs, and then remove the back part as in the image. Time taken: 35 Minutes ATTENTIÓN TO PREVENT THE SHIELD FROM DROPPING, THE USE OF A UNEX CLAMP OR SIMILAR IS RECOMMENDED.
  • Page 40 9. FOOTRESTS • Remove the 5 securing screws (2 Philips 6x16 with large washer, 2 Philips 6x16 with small washer and 1 Philips 4.8x25 self-tapper), and the one joining the two fairings. Time taken: 53 Minutes 10. SIDE COVERS • Remove the 2 securing screws (1 Philips 6x16 with l washer and 1 Philips 3.6x10 self-tapper), and the turn indicator wire.
  • Page 41 1. DISMANTLING FOOTRESTS • See step 9 of the dismantling guide. 2. EXTRACTING COMPLETE FILTER BOX • Extract the 4 (front ) ALLEN Ø 5 screws. • Extract Ø 6 screw (top rear) with back nut. 3. DISCONNECT THE SECONDARY AIR PIPE. 4.
  • Page 42 Remove the water pipe to the carburettor from the supporting tab and pull out the filter, starting at the rear. 6 EXTRACT CARBURETTOR • Loosen the clamp using a ratchet-type tool. • Disconnect the choke cable, petrol pipe and air inlet pipe from the carburettor.
  • Page 43 • Extract the carburettor to gain access to all its parts. N.B. FIT IN REVERSE ORDER, TAKING SPECIAL CARE WITH THE WIRING (PETROL, OIL, WATER).
  • Page 44 ’ ISMANTLING THE MACHINE ISMANTLING THE MACHINE S ENGINE S ENGINE 1) Disconnect the battery. 2) Completely remove the exhaust pipe. 3) Remove the rear wheel. 4) Disconnect the electrical wiring from the magneto. 5) Disconnect the throttle and mixer activating transmis- sions.
  • Page 45 Meters Lithium soap grease, NLGI 33 - Remove the split ring positioned on the external side of the transmission cover. - Remove the drive gear from its housing, de- creasing the tension that the toothed segment applies via the spring; to do so, it is necessary to slightly rotate the toothed segment (see figure).
  • Page 46 EMOVING THE DRIVEN PULLEY EMOVING THE DRIVEN PULLEY - Lock the clutch bell housing with the specific tool. - Remove the nut, the clutch bell housing and the whole of the driven pulley assembly. N.B. THE ASSEMBLY CAN ALSO BE REMOVED WITH THE DRIVE PULLEY IN PLACE.
  • Page 47 - Using a 34 mm socket wrench, remove the clutch locknut. - Loosen the central screw, unloading the spring of the driven pulley assembly. - Separate the components. Specific tooling 020444Y Driven half pulley spring compressor tool NSPECTING THE CLUTCH NSPECTING THE CLUTCH - Check the thickness of the clutch mass friction material.
  • Page 48 - Remove the three guide pins and the movable half pulley. EMOVING THE DRIVEN HALF EMOVING THE DRIVEN HALF PULLEY BEARING PULLEY BEARING - Remove the roller bearing using the specific extractor inser- ted from the lower side of the stationary half pulley CAUTION POSITION THE SEALING EDGE OF THE EXTRACTION PLIERS BETWEEN THE END OF THE BEARING AND THE BUILT-IN...
  • Page 49 Characteristic Standard diameter 0 33,965 ÷ 33,985 mm Stationary driven half pulley/ Minimum diameter allowed after use 0 33,96 mm NSPECTING THE DRIVEN SLIDING HALF NSPECTING THE DRIVEN SLIDING HALF PULLEY PULLEY - Remove the two inner seal rings and the two 0-rings. - Measure the inside diameter of the movable half pulley bushing.
  • Page 50 EFITTING THE DRIVEN HALF PULLEY BEARING - Fit a new ball bearing with the specific tools. - Fit the ball bearing circlip. - Fit the new roller bearing so that the lettering is visible from the outside. CAUTION ADEQUATELY SUPPORT THE HALF PULLEY TO AVOID DA- MAGING THE THREADED END WHILE FITTING THE BEA- RINGS.
  • Page 51 - Reassemble the nut securing the clutch and tighten to the prescribed torque. CAUTION TO AVOID DAMAGING THE CLUTCH NUT, USE A SOCKET WRENCH WITH A SMALL BEVEL. CAUTION POSITION THE UNBEVELLED SURFACE OF THE NUT IN CONTACT WITH THE CLUTCH. Locking torques (N*m) Nut locking clutch assembly on pulley 55 - 60 Nm EFITTING THE DRIVEN PULLEY...
  • Page 52 EMOVING THE DRIVING PULLEY EMOVING THE DRIVING PULLEY - Lock the pulley with the specific tool. - Remove the central nut with the related washer, then remo- ve the drive and the plastic fan. - Remove the fixed half pulley. - Remove the belt, washer and remove the mobile half pulley with its bushing, being careful of the rollers and contrast pla- te fitted loosely on it.
  • Page 53 3) Make sure that the rollers do not have marked facing on the sliding surfaces and that the metal insert does not pro- trude from the edges of the plastic cover. 4) Make sure that the contact plate sliding blocks are intact. - Check that the internal bronze bushing shown in the figure is not abnormally worn and measure inside diameter «A».
  • Page 54 N.B. REPLACE THE NUT WITH A NEW ONE EVERY TIME THE PAR- TS ARE REASSEMBLED ATENCIÓN IT IS VERY IMPORTANT THAT WHEN THE DRIVE PULLEY IS SECURED THAT THE BELT IS FREE INSIDE IT, TO AVOID IN- CORRECTLY TIGHTENING IT WITH LATER DAMAGE TO THE ENGINE SHAFT MM SCALE.
  • Page 55 ISMANTLING OUTPUT PINION SHAFT ISMANTLING OUTPUT PINION SHAFT - Remove the intermediate gearing and the output pinion shaft. - While removing the idler gear, pay attention to the related shoulders. ISMANTLING OUTPUT PINION SHAFT BEARING ISMANTLING OUTPUT PINION SHAFT BEARING - Remove the oil seal and the seeger ring.
  • Page 56 - Position the specific tube on the inner race of the bearing and on the pulley shaft teeth side as shown in the figure. Ex- pel the driven pulley shaft with the aid of a press. Specific tooling 020452y Driven pulley shaft fitting/removing tube NSPECTING THE HUB SHAFT NSPECTING THE HUB SHAFT - Check the three shafts for wear or distortion of the toothed...
  • Page 57 - Heat the hub cover and insert the bearing using the specific punch. - Fit the elastic ring with the concave part on then bearing side. N.B. FIT THE BALL BEARING WITH THE SHIELD FACING THE OIL SEAL. Specific tooling 020151Y Air heater 020376Y Handle for punches 020439Y 17mmguide...
  • Page 58 EFITTING THE UB COVER EFITTING THE UB COVER - Refit the wheel, axle assembly. - Refit the intermediate gear paying attention to the two shim washers. - Apply LOCTITE 510 on the hub cover and refit it with driven pulley shaft. - Refit the 5 screws arid tighten to the, prescribed N.B.
  • Page 59 EFITTING THE FLYWHEEL COVER EFITTING THE FLYWHEEL COVER - Fit the rubber seal on the flywheel connector and around the inlet coolant hose. - Keeping the flywheel connector rubber clamp on the coolant inlet hose, refit the flywheel cover paying attention in inserting the strap in the groove.
  • Page 60 - Extract the flywheel with the specially designed extractor. Specific tooling 020565Y Compass flywheel stop spanner 020162y Flywheel extractor NSPECTING THE FLYWHEEL COMPONENTS NSPECTING THE FLYWHEEL COMPONENTS - Check the flywheel for any distortion that might cause rub- bing on the stator and the pick-up. EFITTING THE FLYWHEEL MAGNETO EFITTING THE FLYWHEEL MAGNETO - Fit the flywheel taking care to properly insert the key.
  • Page 61 EFITTING THE STARTER MOTOR EFITTING THE STARTER MOTOR - Fit a new 0-ring on the starter motor and lubricate it. - Install the starter motor on the crankcase and tighten the two screws with the prescribed torque. N.B. FIT THE REMAINING PARTS AS DESCRIBED IN THE CHAP- TERS CYLINDER, CYLINDER HEAD, VALVE GEAR, LUBRICA- TION, FLYWHEEL AND TRANSMISSION.
  • Page 62 EMOVING THE CYLINDER EMOVING THE CYLINDER PISTON ASSY PISTON ASSY - Carefully remove the cylinder. - Remove the split rings and the wrist pin. CAUTION ALWAYS REPLACE THE WRIST PIN SPLIT RINGS WITH NEW ONES NSPECTING THE SMALL END NSPECTING THE SMALL END - Using an inside micrometer, measure the small end dia- meter N.B.
  • Page 63 NSPECTING THE PISTON NSPECTING THE PISTON - Using a suitable instrument measure the piston diameter. - Evaluate the piston-wrist pin fitting clearance. Characteristic Wrist pin housing: standard diameter 12+0,007+0,012 Wrist pin housing: standard tolerance 0,002-0,011 mm - Measure the external diameter of the piston according to a direction orthogonal to the pin axis.
  • Page 64 NSPECTING THE PISTON RINGS NSPECTING THE PISTON RINGS - Alternatively insert the two piston rings inside the cylinder. - Insert the piston rings in the direction orthogonal to the cylinder axis, using the piston to push them through. - Measure the rings gap using a feeler gauge as shown in the picture.
  • Page 65 Recommended products Selenia Hi Scooter 2 Tech Oil Recommended oil NSPECTING THE TIMING SYSTEM COMPONENTS NSPECTING THE TIMING SYSTEM COMPONENTS CAUTION CHECK THE LEAK TIGHTNESS OF THE REED VALVE ASSY.; NO LIGHT BE VISIBLE BETWEEN VALVE AND HOUSING.
  • Page 66 CRANKCASE - CRANKSHAFT PLITTING THE CRANKCASE HALVES PLITTING THE CRANKCASE HALVES Remove the eight crankcase fasteners. Install the special plate on the flywheel-side half crankcase and proceed by splitting the two halves. Specific tooling 020163y Crankcase splitting plate EMOVING THE CRANKSHAFT EMOVING THE CRANKSHAFT - Install the special tool onto the transmission-side half- crankcase using four M6 screws of adequate length.
  • Page 67 Specific tooling 004499y001 Bearing extractor fitted with parts 004499y006 Bearing extractor fitted with parts 004499y002 Bearing extractor fitted with parts 004499y007 Half rings Using the special tool, remove any bearing which remained on the crankcase. Specific tooling 001467Y007 Bell for bearings external 0 54 mm 001467Y006 20-mm pliers EFITTING THE CRANKSHAFT BEARINGS EFITTING THE CRANKSHAFT BEARINGS...
  • Page 68 NSPECTING THE CRANKSHAFT ALIGNMENT NSPECTING THE CRANKSHAFT ALIGNMENT Using the appropriate specific tools, check the eccentricities of the surfaces of diameters «A»-«B»-« C» are within 0.03 mm (top reading limit for the dial gauge clock); check also the eccentricity of diameter «D», for which a maximum mi- salignment of 0.02 mm is allowed.
  • Page 69 - Let the half-crankcase temperature settle with that of the crankshaft. - Reinstall the crankcase splitting plate WITHOUT installing the crankshaft protection. - During the reassembly process keep the centre thrust screw loose. - Tighten the four fixing screws and then loosen them with the same angle (e.g.
  • Page 70 - Move the crankcase splitting plate backwards as shown in the figure. - Install the special magnetic mounting with its dial gauge, at the end of the crankshaft. - Check the crankshaft axial play. - If the measurements do not match those prescribed, repeat the crankshaft reassembly operation.

  • Page 71: Oil Pump

    - Install a new transmission-side oil seal using the special tool fitted with adapter ring. - The transmission-side oil seal may be recognised by its lar- ger diameter. Specific tooling 020340Y Punch for fitting oil guard magneto and trans- mission OIL PUMP EMOVAL EMOVAL...
  • Page 72 UEL SUPPLY UEL SUPPLY The vehicle is fitted with a membrane pump controlled via the vacuum generated in the intake duct. The tank is there- fore fitted with a hole located at its lowest point, which allows fuel to flow to the pump and then to the carburettor. To check the pump performance, the following mass flow measurement may be carried out: 1) Start the engine, warm it up to the standard operating...
  • Page 73 SEBAC F ORKS Forks assembly Stem-plate subassembly Fork stem securing washer Fork arm securing safety ring 10M150x50 hexagonal bolt 8M125x35 ZnB Allen bolt Arm securing bolt washer Fork arm plug Fork pipe plug ring Fork spring Hydraulic piston spring Hydraulic piston ring Fork arm retainer washer Fork arm pipe Hydraulic pipe...
  • Page 74 MARZOCCHI F ORKS 8M125x30 Allen bolt Right hand end point hydraulic assembly Fork arm securing ring Fork arm guide bush Arm guide bush washer Fork arm retainer Oil seal ring Fork arm dust guard Fork arm assembly 8M125x30 Allen bolt Arm securing bolt washer Fork plug ring Fork plug assembly...
  • Page 75 DISMANTLING FRONT SUSPENSION DISMANTLING FRONT SUSPENSION ATTENTION TO CARRY OUT THE PROCESS OF DISMANTLING THE FOR- KS WITHOUT REMOVING THEM FROM THE BOTTOM PLATE. TO DO SO, HOLD THE FORKS IN A BENCH VICE BY THE STEERING COLUMN, THEREBY PREVENTING THEM FROM BEING SCRATCHED.
  • Page 76 Extract the spring and the preload spacer. - Extract the oil seal dust guard together with its security circlip. - Firmly separate the bar from the fork stem. Extract the elements: - Dust guard (1). - Oil seal (2). - Washer (3). - Scraper (4).
  • Page 77 - Proceed with cleaning and degreasing all the front sus- pension components, so that they can be subsequently chec- ked. NSPECTING THE FRONT FORKS NSPECTING THE FRONT FORKS - Check the degree of wear on the suspension bar guide bush. Replace it in the event of it being damaged on over 30% of its total surface.
  • Page 78 Reassemble the assembly, paying special attention to the tig- htening of the fork stem, as well as the fitting of the oil seal, putting a little oil on its edges and inserting it with the aid of the special tool. Refill the hydraulic fluid and do not forget to insert the preload bush between the spring and the closing plug.
  • Page 79 Swinging arm assembly Swinging arm assembly 14M200 ZnB Hexagonal nut Shock absorber assembly 10M150x60 ZnB Allen bolt D10D125 ZnB Washer 10M150 ZnB Hexagonal nut 10M150x60 ZnB Allen bolt Shock absorber bottom separator bush Swinging arm outer stop bush Swinging arm shaft bush Chain cover Bolt 4.8 x 13 Flat washer...
  • Page 80 ISMANTLING ISMANTLING 1. Place the motorcycle on a flat surface. WARNING ENSURE THAT THE MOTORCYCLE IS SUPPORTED FIRMLY AND THERE IS NO RISK OF IT FALLING. 2. Extract: - Rear wheel. - Wheel sprocket. - Brake disk. - Rear calliper. 3.
  • Page 81 RONT WHEEL DIAGRAM Front wheel rim 120/70-14in front tyre Wheel air valve assembly M14x150 wheel axle nut protector Wheel separator bush C/ALL 10M 150x60 D912 8ZnB bolt DIN 125-A-ST front wheel axle. D15 DIN 125-A-ST flat washer D-934 wheel axle head nut D.245 front brake disk FR.(6x20) Zn.B10.9 disk securing bolt Bearing...
  • Page 82 ISMANTLING ISMANTLING WARNING - ENSURE THAT THE MOTORCYCLE IS SUPPORTED FIRMLY AND THERE IS NO RISK OF IT FALLING. - PLACE THE MOTORCYCLE ON A FLAT SURFACE. 1. Extract: - Front brake calliper (Bolts 1 and 2). 2. Extract: - Nut protecting cover. - Nut (left side).
  • Page 83 3. Check: - Spokes. Warps/damage => Replace. 4. Measure: - Distortion of the front wheel Above that specified => Replace. Distortion limits for the front wheel: Radial (a): 0,5 mm Lateral (b): 0,8 mm 5. Check: - Front wheel bearings. Bearings allow play in the wheel hub or the wheel does not turn freely =>...
  • Page 84 ISMANTLING THE FRONT DISK CALLIPER ISMANTLING THE FRONT DISK CALLIPER - Loosen the banjo bolt (1) from the bottom end of the brake pipe and tighten it slightly. - Unscrew the calliper mounting bolts (2) and separate the calliper (3) backwards from the disk. PRECAUTION CLEAN OFF ANY SPILT BRAKE FLUID REMAINS IMMEDIA- TELY.
  • Page 85 Extracting the front brake pads. - Remove the front brake calliper (see “Dismantling the front brake calliper” in this chapter). Extract: - Pad springs (1). - Pin. - Brake pads (2). Fitting the front brake pads - Press the calliper pistons in manually. - Fit the pads inside the calliper.
  • Page 86 N.B. THE MASTER CYLINDER (1) IS INCORPORATED INTO THE FRONT BRAKE LEVER ASSEMBLY. - EXTRACT THE SCREWS (2) AND THE FRONT BRAKE LEVER ASSEMBLY. PRECAUTION CLEAN OFF ANY SPILT BRAKE FLUID REMAINS IMMEDIA- TELY. Extract: - Brake lever mounting bolt and nut. - Brake lever.
  • Page 87 Checking the brake calliper main cylinder: - Check that the anti-dust boots are not damaged. If they are, change them. - Check that the piston return is not damaged. If it is, renew it. - Check that the relief port and feed port are not blocked. if the relief port is blocked, the brake pads will bind on the disk.
  • Page 88 Brake disk distortion: - Raise the motorcycle on the jack so that the tyre is clear of the ground. - To check the front disk, turn the handlebars completely to one side. - Place a dial calibrator against the disk (A) as shown, and measure the disk’s deviation from centre as the tyre is turned by hand (B).
  • Page 89 Purge the air completely from the master cylinder using this procedure. - Remove the transparent plastic cap from the bleed nipple and place the other end of the pipe in a container. - Repeat the following procedure until there is no air left emerging from the plastic pipe: - Pump the brake lever until it becomes hard and holds the brakes down.
  • Page 90 3) DO NOT MIX TWO TYPES OR BRANDS OF FLUID FOR USE IN THE BRAKE. THIS LOWERS THE BRAKE FLUID EVA- PORATION POINT AND MAY RESULT IN THE BRAKES NOT WORKING EFFICIENTLY. IN ADDITION, IT MAY CAUSE DE- TERIORATION OF THE BRAKE PARTS. 4) DO NOT LEAVE THE RESERVOIR CAP OFF AT ANY TIME, TO PREVENT CONTAMINATION OF THE FLUID.
  • Page 91 SSEMBLING THE FRONT WHEEL SSEMBLING THE FRONT WHEEL Reverse the “DISMANTLING” procedures. Take care with the following points: 1. Lubricate: - Front wheel axle. - Bearing. - Retaining rings. Recommended lubricant: Lithium soap based grease 2. Fit: - Front wheel 3.
  • Page 92 HEEL DIAGRAM Brake pad securing spring GP1 front wheel Rear brake calliper bleed nipple 120/70-14in rear tyre 5M80 DIN-982 self-locking nut Air valve assembly D5 ZnB flat washer Rear wheel axle assembly Rear brake puller 14M200 ZnB nuts Main connecting rod securing bolt GP1 drag plate Washer (6x20) Zn.B10.9 brake disk securing bolt...
  • Page 93 ISMANTLING ISMANTLING WARNING - ENSURE THAT THE MOTORCYCLE IS SUPPORTED FIRMLY AND THERE IS NO RISK OF IT FALLING. - PLACE THE MOTORCYCLE ON A FLAT SURFACE. 1. Extract: - Wheel axle (1). - Spacer. N.B. ON WITHDRAWING THE WHEEL AXLE, THE SPACER WILL DROP DOWN.
  • Page 94 Fitting the rear calliper - Fit the bottom end of the flexible brake pipe and the calliper. Fit the wheel axle, the brake puller and the flexible hose se- curing clips. Nominal torque (wheel axle): 110-130 N.m (11-13 kgf.m) Tighten to nominal torque (brake puller): 35-40 N.m (3,5 –...
  • Page 95 WARNING DO NOT ATTEMPT TO RIDE THE MOTORCYCLE UNTIL THE BRAKE PEDAL IS OPERATING FULLY. PUMP THE LEVER UN- TIL THE PADS ARE AGAINST THE DISK. IF NOT, THE BRAKE WILL NOT WORK THE FIRST TIME THE PEDAL IS USED. Inspecting the pads for wear - Removing the rear brake pads.
  • Page 96 Checking the rear main cylinder (visual check) - Extract the main cylinder (consult “Extracting the rear main cylinder” in this section). - Dismantle the rear main cylinder. - Check that there are no scratches, corrosion or holes in the inner walls of the main cylinder and on the outer part of each piston.
  • Page 97 Brake disk wear - Measure the thickness of the disks (A) at the point where they are most worn. - If the disk is more worn than specified in the service limit, renew it. Measurement area (B). Standard brake disk thickness: 3.3 ÷...
  • Page 98 Extract: - Bolts (1). - Reservoir cap (2). - Fill the reservoir with brake fluid up to the top reservoir line. - With the cap removed, pump the brake lever slowly several times until no bubbles can be seen rising through the liquid. Purge the air completely from the master cylinder using this procedure.
  • Page 99 WARNING WHEN WORKING WITH THE DISK BRAKE, TAKE THE FO- LLOWING PRECAUTIONS: 1) NEVER RE-USE BRAKE FLUID. 2) DO NOT USE FLUID FROM A CONTAINER THAT HAS BEEN LEFT OPEN OR HAS BEEN LEFT UNUSED FOR A PRO- LONGED PERIOD OF TIME. 3) DO NOT MIX TWO TYPES OR BRANDS OF FLUID FOR USE IN THE BRAKE.
  • Page 100 NSPECTING THE REAR WHEEL NSPECTING THE REAR WHEEL 1. Inspect: - Rear wheel axle - Rear wheel - Rear wheel bearings - Retaining rings See the “WHEEL AND REAR BRAKE” section 2. Measure: - Distortion of the rear wheel See the “WHEEL AND REAR BRAKE” section ITTING THE REAR WHEEL ITTING THE REAR WHEEL Reverse the “DISMANTLING”...
  • Page 101 ISMANTLING ISMANTLING 1. Place the motorcycle on a flat surface. WARNING ENSURE THAT THE MOTORCYCLE IS SUPPORTED FIRMLY AND THERE IS NO RISK OF IT FALLING. 2. Extract: - Pinion See the “DISMANTLING THE ENGINE” section in CHAP- TER 5. 3.
  • Page 102 NSPECTING THE DRIVE CHAIN NSPECTING THE DRIVE CHAIN 1. Inspect: - Chain stiffness Stiffness => Clean and lubricate, or replace. 2. Inspect: - Drive chain (1). - Chain sprocket (2). More than ½ tooth of wear => Replace the whole chain. 3.
  • Page 103 ITTING THE CHAIN SPROCKET AND THE DRIVE CHAIN ITTING THE CHAIN SPROCKET AND THE DRIVE CHAIN 1. Fit: - Chain sprocket assembly 2. Fit: - Drive chain (1). - Coupling link (2). - Coupling plate (3). 3. Fit: - Circlip (1). ATTENTION FIT THE CHAIN COUPLING CIRCLIP FACING IN THE DIREC- TION INDICATED IN THE FIGURE...
  • Page 104 YSTEM BLEED YSTEM BLEED Fill up the circuit through the expansion tank up to the max level mark. Secure a rubber hose to the bleed joint on the head and insert it inside the expansion tank filler hole. Loo- sen the joint and, if necessary, top-up with fresh coolant. Start up the engine and wait until only coolant exits the hose, hence tighten the joint on the cylinder head.
  • Page 105 - Remove the split ring from the shaft together with the bea- rings. - Remove the steel washer. - Using the air heater, warm up the crankcase in the area around the water pump bearings as shown in the picture. -With the aid of the special tool, loosen the impeller shaft turning the spanner clockwise (left-handed thread).
  • Page 106 - For refitting use a new oil seal. - Position the new oil seal on the special tool with the main lip facing the bearings as shown in the picture. - Lubricate the oil seal and push it home using the special tool as shown in the picture Specific tooling 020168y Oil seal fitting drift on half-crankcase.
  • Page 107 Using the air heater, warm up the water pump bearing housing, without directing the air flux directly aginst the oil seal. - Lubricate the end of the water pump shaft on the oil seal side, using the recommended product. Recommended products Lithium soap grease NLGI 33 THERMOSTAT EMOVAL...
  • Page 108 CAUTION AVOID CONTACT BETWEEN THERMOSTAT AND CONTAI- NER AND BETWEEN THERMOMETER AND CONTAINER FOR A CORRECT TEST PERFORMANCE. Specific tooling 020331 Y Digital multimeter 020151Y Air heater Characteristic Thermostat check: Opening start temperature 60±2°C EFITTING EFITTING - Refit the thermostat onto the head, following the removal operations in the reverse order, and paying attention in in- serting the groove on the thermostat on the reference on the head.
  • Page 109 GP1 50 WIRING DIAGRAM O - Orenge GR - Green B - Black BR - Brown W - Whaite G - Grey Y - Yellow BL - Blue R - Red P - Pink VI - Violet Starter relay Front headlight Starter motor 12v 35W/H8 front right hand dipped headlight 4 amp fuse...
  • Page 110 GP1 50 SWITZERLAND WIRING DIAGRAM O - Orenge GR - Green B - Black BR - Brown W - Whaite G - Grey Y - Yellow BL - Blue R - Red P - Pink VI - Violet Front headlight Oil reserve sensor 12v 35W/H8 front right hand dipped headlight Choke resistance...
  • Page 111 HECKING CONNECTORS HECKING CONNECTORS Check for corrosion, damp etc. in the connectors. 1. Disconnect: - Connectors 2. Dry each of the terminals with compressed air. 3. Connect and disconnect two or three times. 4. Pull the conductor to check if it is loose. 5.
  • Page 112 NSPECTION STEPS NSPECTION STEPS Using a multimeter, check the circuit between the terminals to make sure that they are correctly connected. Replace the component if any of the combinations gives an incorrect rea- ding. N.B. - SWITCH THE “ON” AND “OFF” SWITCH ON AND OFF SEVERAL TIMES.
  • Page 113 GNITION Electronic central unit Magneto Pick-Up Ignition key switch Spark plug Control circuit Digital instruments unit...
  • Page 114 UTOMATIC CHOKE AND LIGHTS Magneto Voltage regulator Automatic choke Rear light Digital instruments unit Front sidelight bulbs Dipped headlight bulbs Main beam headlight bulbs...
  • Page 115 ATTERY RECHARGE AND STARTING Magneto Voltage regulator 7.5 amp fuse 12v 6AH battery Starter relay Starter motor Rear light with LED Ignition key switch Starter button Stop buttons...
  • Page 116 EVEL INDICATORS Voltage regulator Ignition key switch 7.5 amp fuse 12v 6AH battery Starter button Starter relay Starter motor Stop buttons Fuel level sensor Coolant temperature sensor Mixer oil level sensor Phonic wheel Digital instruments unit Check Control...
  • Page 117 URN INDICATORS AND HORN Voltage regulator Ignition key switch 7.5 amp fuse 12v 6AH battery Horn button Horn Turn indicator bulbs Turn indicator switch Digital instruments unit Diode box...
  • Page 118 HECKS AND INSPECTIONS HECKS AND INSPECTIONS Checks to be carried out in the event of ignition faults and/or missed sparking. Check the spark plug (clean with a metal brush. Remove all incrustations. Blow with an air jet and replace if necessary). Without removing the stator, perform the inspections given below.
  • Page 119 GNITION CIRCUIT GNITION CIRCUIT All checks on the electrical equipment involving the discon- nection of cables (checks on ignition circuit connections and devices) are to be carried out while the engine is switched off. Should the engine be running, the C.D.I, module could suffer irreparable damage.
  • Page 120 Interventions FAULT 1 Replace the regulator as definitely faulty. FAULT 2 a) Check the output from the stator gives the correct voltage: detach the stator connector, interpose an AC tester between the grey-blue and black cables, and check the output voltage is within the prescribed limits.
  • Page 121 FAULT 4 a) Interposing the AC tester between the black and yellow cables on the regulator, check the generator output voltage is within the prescribed values (this measurement must be carried out with the battery detached). In the event of ano- malies, replace the stator;...
  • Page 122 - Repeat the same operation with the terminals inserted between pins 5 (+) and 6 (-) and check for the presence of battery voltage with the ignition switch onto ON. If unsucce- ssful, check the ground cable on the regulator. - If the checks given above are unsuccessful, jump pins 5 and 7 on the connector, turn the key-switch onto ON and turn the turn signal switch alternately from left to right to visualize the...
  • Page 123 USES USES The electrical system is protected by a fuse located on the r.h.s. of the battery bay. To replace it, lift the seat, remove the battery access door and then the transparent fuse cover. Ignition system, headlight, and taillight are not protected by the fuses.
  • Page 124 - Upturn the electrolyte container with the six closing surfa- ces aligned with the six battery filling holes. - Push the container down with enough force to break the seals. The electrolyte should then begin to flow into the bat- tery.
  • Page 125 ATTERY INITIAL CHARGE Accepting that a battery requiring no maintenance can be used only once it has been filled with electrolyte, the battery may be incapable of starting the engine in the cases indica- ted in the following table, where it is necessary firstly to give it an initial charge.
  • Page 126 TAKE CARE KEEP THE BATTERY AWAY FROM SPARKS OR NAKED FLA- MES DURING THE CHARGING PROCESS, SINCE THE BAT- TERY GIVES OFF AN EXPLOSIVE MIXTURE OF HYDROGEN AND OXYGEN GASES. WHEN USING A BATTERY CHARGER, CONNECT THE CHARGER TO THE BATTERY BEFORE PLU- GGING IT IN.
  • Page 127 N.B. CARRY OUT THE MEASUREMENT WITH A DIGITAL VOLT- METER (A) THAT CAN READ VOLTAGES WITH DECIMAL FI- GURES. * IF THE READING IS BELOW THAT SPECIFIED, THE BATTERY NEEDS TO BE RECHARGED. Battery terminal voltage Standard: 12.5v or higher - Measure the voltage at the battery terminals.
  • Page 129 This section is for solutions to solve problems. A list of possible causes is provided for each problem and reated operations. ENGINE OOR PERFORMANCE CAUSES POSSIBLE WORK Fuel pump defective or vacuum tube dama- Replaced pump or tubing Carbirettor jets colgged or dirty Remove.
  • Page 130 REAR WHEEL SPINS AT IDLE EAR WHEEL CAUSES POSSIBLE WORK Idle speed set too high Adjust slow running speed and C.O. if necessary Faulty clutch Check springs/weight of friction and clutch housing Air filter box not sealed Refit filter box. Replace if it is damaged TARTING DIFFICULTY CAUSES POSSIBLE WORK...
  • Page 131 EXCESSIVE OIL CONSUMPTION/EXHAUST SMOKE CAUSES POSSIBLE WORK Excessive carbon deposits on cylinder ports Decoke and in combustion chamber ENGINE TENDS TO CUT-OFF AT FULL THROTTLE NGINE STOPS AT FULL THROTTLE CAUSES POSSIBLE WORK Maximum jet dirty - lean carburetion Wash with solvent and dry with compressed air. Fuel cock failure Check that the fuel comes through the feed pipe when the engine is started, with the throttle closed;...
  • Page 132 HIGH FUEL CONSUMPTION XCESSIVE CONSUMPTION CAUSES POSSIBLE WORK Air filter clogged or dirty Clean Inefficient starter Check: electric connections, circuit continuity, mecha- nical sliding, and presence of power EXCESSIVE EXHAUST NOISE OISE INCREASE CAUSES POSSIBLE WORK Secondary air metallic tube deteriorated Check the seal of the tubing against crankcase and secon- dary air box.
  • Page 133 SAS MALFUNCTIONS OOSENESS OF RUBBER UNION OF SECONDARY AIR TUBE TO SILENCER CAUSES POSSIBLE WORK Secondary air reed blocking Replace Secondary air filter clogged Clean filter and box Secondary air union to silencer clogged Decoke the union taking care not to let the carbon deposits fall inside the silencer TRANSMISSION AND BRAKES - CLUTCH GRABBING OR PERFORMING INA- DEQUATELY...
  • Page 134 INSUFFICIENT BRAKING RAKING SYSTEM FAILURE CAUSES POSSIBLE WORK Insufficient braking force The rear brake (drum brake) is adjusted by setting the relative registers (on the wheel), remembering that the wheels must turn freely when the brake levers are fully released. The braking action should start when brake levers are pulled at 1/3 of their travel.

  • Page 135: Electrical System

    ELECTRICAL SYSTEM ATTERY CAUSES POSSIBLE WORK Battery This one component of the system needs checking more frequently and servicing more carefully than any other. If the vehicle is to stand idle for any length of time (one month or longer), the battery will need recharging pe- riodically.
  • Page 136 HEAVY STEERING CAUSES POSSIBLE WORK Unacceptable tightening Check the tightening torque of the upper and lower collar. If the steering fails to turn smoothly even when correctly tightened, inspect the bearing races and re- place if they show signs of uneven wear. EXCESSIVE STEERING PLAY CAUSES POSSIBLE WORK...
  • Page 137 SUSPENSION OIL LEAKAGE CAUSES POSSIBLE WORK Rear shock-absorber faulty Replace the shock-absorber assembly Inner fork hydraulic damper damaged Replace the hydraulic damper...

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