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Sym NCA250 Service Manual

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PREFACE
PREFACE
This shop manual describes the technical feature and
servicing procedures for the SANYANG NCA250.
All information, illustrations, directions and
specifications included in this publication are base on
SANYANG NCA250.
SANYANG reserves the right to make changes at any
time without notice and without incurring any
obligation whatever.
SANYANG INDUSTRY CO.,LTD.
SERVICE DIVISION

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Summary of Contents for Sym NCA250

  • Page 1 PREFACE PREFACE This shop manual describes the technical feature and servicing procedures for the SANYANG NCA250. All information, illustrations, directions and specifications included in this publication are base on SANYANG NCA250. SANYANG reserves the right to make changes at any time without notice and without incurring any obligation whatever.

  • Page 2: Table Of Contents

    CONTENTS CONTENTS GENERAL INFORMATION ................1 INSPECTION/ADJUSTMENT...............2 LUBRICATION SYSTEM................3 ENGINE REMOVAL/INSTALLATION ............4 CYLINDER HEAD/VALVE................5 CYLINDER/PISTON..................6 CLUTCH/OIL PUMP/GEAR SHIFT ..............7 A.C. GENERATOR ..................8 CRANK SHAFT/CRANK CASE/TRANSMISSION ........9 CARBURETOR.....................10 HEADLIGHT/STEERING/FRONT WHEEL/FRONT FORK ......11 REAR WHEEL/REAR SUSPENSION ............12 BATTERY/CHARGING SYSTEM ..............13 IGNITION SYSTEM..................14 SWITCHES/HORN..................15 WIRING DIAGRAM..................16...

  • Page 3: General Information

    1.GENERAL INFORMATION SERVICE RULES .......1-1 TORQUE VALUES ......1-3 SPECIFICATIONS......1-2 TROUBLE SHOOTING ...... 1-4 SERVICE RULES: (1)Use new packings, gaskets,O-rings and cotter (5)Clean all removed parts in or with solvent, and pins space and clipes whenever reassembling. lubricate their sliding surfaces upon disassembly. (2)When tightening bolts or nuts, begin on center or (6)Coat or fill parts with specified grease where larger diameter bolts and tighten them in criss-...

  • Page 4: Specifications

    1.GENERAL INFORMATION SPECIFICATIONS ITEM NCA250 Overall length 2180mm Overall width 960mm Overall height 1130mm DIMENSIONS Wheel base 1480mm Ground clearance 160mm Dry weight 175kg Type Double pipe Front suspension and travel Telescope 165mm Rear suspension and travel Swing arm 63mm...
  • Page 5 1.GENERAL INFORMATION ENGINE TIGHTEN LOCATION Q'TY THREAD DIA(mm) TORQUE(kgf ¡ ¤ Oil plate pan screw 80~120 Crank shaft bolt 180~220 Crank shaft nut 70~110 Cylinder head nut 80~120 Cylinder head cover 80~120 Cam shaft sprocket bolt 80~120 Crank case bolt 80~120 L crank case cover bolt 80~120...

  • Page 6: Inspection/Adjustment

    1.GENERAL INFORMATION Torque specifications listed below for respective locations. TROUBLE SHOOTING A. HARD START OR CANNOT START inspection adjustment cause symptom loosen carburetor drain screw, check inner side for no gasoline in the tank gasoline fuel tube between gasoline tank and carburetor clogged.
  • Page 7 1.GENERAL INFORMATION B. ROTATION ROUGH (LACKS POWER) cause inspection adjustment symptom start engine and slightly air cleaner clogged apply fuel fuel tube clogged air hole on the fuel tank cap blocked exhaust tube clogged engine speed up engine speed can't up auto air cut faulty carburetor vacuum diaphragm worn adjust ignition timing use...
  • Page 8 1.GENERAL INFORMATION C. ROTATION ROUGH (ESPECIALLY IN THE LOW SPEED AND IDLE SPEED) inspection adjustment cause symptom ignition timing adjustment faulty CDI unit normal abnormal faulty A.C.Generator valve gap adjust faulty adjust carburetor fuel adjusting screw lean mixture(loosen screw) adjust OK adjust faulty rich mixture(tighten screw) carburetor gasket...
  • Page 9 1.GENERAL INFORMATION D. ROTATION ROUGH (HIGH SPEED) cause symptom inspection adjustment ignition timing adjustment faulty CDI unit normal abnormal faulty pulse generator valve clearance adjustment poor adjustment normal abnormal valve seat faulty check auto fuel cup for fuel supplied. too little fuel in the fuel tank normal abnormal fuel tube, fuel filter clogged...
  • Page 10 1.GENERAL INFORMATION E. POOR CHARGE (BATTERY OVER DISCHARGE OR OVER CHARGE) inspection adjustment symptom cause measure battery voltage. and then start engine battery voltage battery voltage rise to reach battery life can't rise normal value,after faulty battery engine stops, the voltage return to original.
  • Page 11 1.GENERAL INFORMATION F.SPARK PLUG NO SPARK cause Inspection adjustment symptom replace with new spark plug and test again. spark wear of spark strong original spark no spark plug faulty Check spark cap and high voltage cable for slack no slack slack spark plug cap slack...
  • Page 12 2.INSPECTION/ADJUSTMENT ENGINE FRAME MAINTENANCE SCHEDULE .....2-2 AIR CLEANER........2-12 SERVICE INFORMATION ....2-3 CLUTCH ADJUSTMENT ....2-12 ENGINE OIL/OIL FILTER ....2-4 BRAKE ADJUSTMENT ..... 2-13 SPARK PLUG........2-5 DRIVE CHAIN ADJUSTMENT ..2-14 COMPRESSION TEST.......2-6 WHEELS/RIM........2-15 VALVE CLEARANCE ......2-7 SUSPENSION ........2-16 IGNITION TIMING ......2-8 STEERING ........

  • Page 13: Maintenance Schedule

    2.INSPECTION/ADJUSTMENT MAINTENANCE SCHEDULE Maintenance Every Every Every Every 300KM kilometer 1000KM 3000KM 6000KM 12000KM Item Maintenance 1 Month 3 Months 6 Months 1 Year Check Items Interval Air cleaner Gasoline filter Oil filter Replacement for every 5000KM R Oil filter screen Cleaning for every 5000km C Engine Oil Replacement for every 1000KM R...

  • Page 14: Service Information

    2.INSPECTION/ADJUSTMENT SERVICE INFORMATION SPECIFICATLON ENGINE Clutch lever free play 10-20mm Drive chain stack 10-20mm Oil capacity 1.1¡ « 1.5 liter Front brake lever free play 10-20mm Spark plug gap A6RTC Rear brake pedal free play 20-30mm Spark plug gap 0.6-0.7mm Throttle grip free play 2-6mm Valve clearance IN...
  • Page 15 2.INSPECTION/ADJUSTMENT OIL/OIL FILTER OIL LEVEL CHECK Start and warm up the engine for few minutes,then stop the engine. Check the oil level with oil level gauge after a few minutes. If the oil level is near the lower mark,fill the crankcase to the upper level mark with the recommended grade oil.

  • Page 16: Spark Plug

    2.INSPECTION/ADJUSTMENT OIL FILTER SCREEN CLEANING Remove the drain bolt, and drain the engine oil. Remove the right crankcase cover. Remove the pump. Clean the oil filter screen with compressed air. Assemble the filter screen in reverse order of disassemble. OIL FILTER SPARK PLUG Disconnect the spark plug cap and remove the spark plug .

  • Page 17: Compression Test

    2.INSPECTION/ADJUSTMENT COMPRESSION TEST Warm up the engine. Stop the engine .Remove spark plug .Insert the compression gauge. ELECTRICAL Push in the choke lever .Open the throttle grip fully. START ENGINE Electrical start engine several times. NOTE: Watch for compression leaking at the gauge connection.
  • Page 18 2.INSPECTION/ADJUSTMENT VALVE CLEARANCE ALIGN MARK NOTE: Inspect and adjust the valve clearance while the engine is cold. Remove the timing inspection hole cap and crankshaft hole cap. Rotate the generator rotor counterclockwise and align the “T”mark on the generator rotor with the index mark in the left crankcase ALIGN (piston must be at T.D.C.of the compression...

  • Page 19: Ignition Timing

    2.INSPECTION/ADJUSTMENT Install the valve adjuster caps and generator cap. NOTE: Check the O-ring for damage and spread oil before installing the caps. O-RING IGNITION TIMING The C.D.I.ignition timing is not adjustable. If the ignition timing is not correct ,check the C.D.I.unit and A.C.generator and replace any faulty parts.
  • Page 20 2.INSPECTION/ADJUSTMENT Inspect the C.D.I unit with C.D.I tester. Replace the faulty C.D.I unit. SWITCH C.D.I. normal C.D.I faulty 1. OFF no sparks ------- 2. P no sparks ------- 3. EXT no sparks sparks 4. ONI sparks no sparks 5. ONZ sparks no sparks CAM CHAIN TENSIONER...

  • Page 21: Throttle Grip Adjustment

    2.INSPECTION/ADJUSTMENT CARBURETOR THROTTLE GRIP FREE PLAY Check throttle grip free play. Free play:2-6mm ADJUSTER NUT THROTTLE GRIP ADJUSTMENT Loosen the lock nut and turn the adjuster to adjust. 2-10...

  • Page 22: Idling Speed Adjustment

    2.INSPECTION/ADJUSTMENT IDLING SPEED ADJUSTMENT Warm up the engine. Turn the stop screw to obtain the idling speed of 1100rpm. Turn the air screw to the maximum speed,then turn the stop screw to obtain the specified idling speed. Idling speed:1500¡ À 100 rpm NOTE: Turn the air screw clockwise for making fuel –air mixture lean.

  • Page 23: Air Cleaner

    2.INSPECTION/ADJUSTMENT AIR CLEANER Remove the left side cover. Remove the air cleaner cover. Remove the air cleaner element. NOTE: Clean the cleaner element periodically.(Refer to maintenance schedule.) SCREWS Assemble air cleaner element in reverse order of AIR CLEANER ELEMENT disassemble. CLUTCH ADJUSTMENT CLUTCH LEVER FREE PLAY Measure the clutch free play at the tip of the clutch...

  • Page 24: Brake Adjustment

    2.INSPECTION/ADJUSTMENT FREE PLAY ADJUSTMENT ADJUSTER Loosen the lock nut and turn the adjuster. Turn the adjuster ,clockwise for decreasing the free play ,counterclockwise for increasing the free play. LOCK LEVER ADJUSTER NUT Or adjust clutch lever adjuster nut. BRAKE ADJUSTMENT FRONT BRAKE LEVER FREE PLAY Measure the brake free play at the tip of the brake 10~20mm...

  • Page 25: Drive Chain Adjustment

    2.INSPECTION/ADJUSTMENT REAR BRAKE PEDAL FREE PLAY Measure the brake pedal free play before the brake start to engage. 20~30mm Free play :20-30mm REAR BRAKE PEDAL ADJUSTMENT Turn the adjuster clockwise for decreasing the clearance ,counterclockwise for increasing the clearance. CAUTION: Keep the adjuster at the right position.
  • Page 26 2.INSPECTION/ADJUSTMENT Loose the rear wheel axle nut for adjusting. Turn the adjusting nuts on both adjusters as necessary. CAUTION: Tighten the axle nut. TORQUE:1000-1200 ¡ ¤ Recheck the drive chain slack and free wheel rotation. Lubricate the drive chain with chain lubricant. ADJUSTING NUTS WHEEL/RIM Front 2.25 kg/c ©...

  • Page 27: Rear Suspension

    2.INSPECTION/ADJUSTMENT SUSPENSION FRONT SUSPENSION Check the action of the front forks by compressing them several times with the front brake applied . If there are abnormal noises or rattles ,check all the fasteners and tighten them to the specified torque. TORQUE: Front fork top bridge bolt :100-140 kgf ¡...
  • Page 28 2.INSPECTION/ADJUSTMENT STEERING Raise the front wheel off the ground and check that the handlebar rotates freely.If the handlebar moves unevenly ,binds or has vertical movement,adjust the steering head nut. BATTERY Inspect the battery fluid level ,if the fluid level nears the lower level mark,fill with distilled water to the upper level mark .

  • Page 29: Stoplight Switch

    2.INSPECTION/ADJUSTMENT HEADLIGHT AIM Adjust vertically by turning headlight up and down with the headlight bolts loosening. Fasten the bolts after adjustment. NUTS ADJUSTING NUT STOPLIGHT SWITCH The stoplight should come on when the brake pedal is depressed 20mm from the standard pedal position.If the action is abmormal, adjust by turning the stoplight switch adjusting nut.

  • Page 30: Lubrication System

    3.LUBRICATION SYSTEM CAM SHAFT OIL LINE OF CAM SHAFT PISTON MAIN SHAFT OIL ORIFICE OF CRANKSHAFT OIL PUMP OIL FILTER COUNTER SHAFT...

  • Page 31: Trouble Shooting

    3.LUBRICATION SYSTEM TROUBLE SHOOTING ...... 3-1 SERVICE INFORMATION ....3-1 TROUBLE SHOOTING OIL LEVEL TOO LOW 1. Natural consumption 2. Oil leaks 3. Worn piston rings OIL CONTAMINATION 1. Oil not changed often enough 2. Faulty cylinder head gasket OIL PRESSURE TOO LOW 1.

  • Page 32: Engine Removal/Installation

    4.ENGINE REMOVAL/INSTALLATION SERVICE INFORMATION ....4-1 ENGINE INSTALLATION ....4-5 ENGINE REMOVAL ......4-2 SERVICE INFORMATION GENERAL INSTRUCTIONS The following parts can be serviced with the engine installed on the frame: Generator Clutch Oil pump Cam shaft / Rocker arm Shift spindle Cam chain tensioner The following parts must be serviced with the engine removed off the frame: Cylinder head...

  • Page 33: Engine Removal

    4.ENGINE REMOVAL/INSTALLATION ENGINE REMOVAL Drain the engine oil. Disconnect the fuel tubes and all connect tubes. Remove the right and left side covers. LEFT CRANKCASE Remove the gear change pedal and left crank case RR.COVER rear cover. GEAR CHANGE Disconnect the A.C. generator wire of the connector and remove the generator wire.
  • Page 34 4.ENGINE REMOVAL/INSTALLATION Remove the clutch cable. CLUTCH CABLE Remove the spark plug cap. Remove the muffler. CLIP Loosen carburetor clip. Separate the carburetor pipe and the cylinder head by removing the attaching bolts. Remove the crankcase breather tube. BREATHER TUBE Loosen the rear wheel axle nut.
  • Page 35 4.ENGINE REMOVAL/INSTALLATION Remove the front engine hanger bolt. NOTE: Places jack or padded block under the engine before removing the front engine hanger. Disconnect the starter motor wire. FRONT ENGINE HANGER BOLT BOLTS Remove the 10mm bolts of the rear engine hanger. Remove the engine.

  • Page 36: Engine Installation

    4.ENGINE REMOVAL/INSTALLATION ENGINE INSTALLATION Follow the reverse procedure of removal to install the engine. Notice the following items during installation: Route all wire harnesses and cables properly. Adjust the throttle grip free play (P2-10) Adjust the clutch lever free play (P2-12) Adjust the drive chain slack (P2-14) Fill the crankcase with the recommended grade oil to the proper level.

  • Page 37: Cylinder Head/Valve

    5. CYLINDER HEAD/ VALVE TROUBLE SHOOTING.......5-1 VALVE GUIDE REPLACEMENT..5-8 SERVICE INFORMATION ....5-2 ... 5-9 VALVE SEAT INSPECTION/REFACING CAM SHAFT REMOVAL ....5-3 VALVE SEAT GRINDING....5-10 ..5-4 CYLINDER HEAD ASSEMBLY ..5-13 CYLINDER HEAD/ROCKER ARM REMOVAL CYLINDER HEAD DISASSEMBLY ..5-6 CYLINDER HEAD INSTALLATION ..

  • Page 38: General Instructions

    5.INSPECTION/ADJUSTMENT SERVICE INFORMATION GENERAL INSTRUCTIONS Camshaft, rocker arm shaft and rocker arm can be serviced with the engine installed on the frame. Camshaft lubrication oil is fed to the cylinder head through an oil control orifice in the engine case. Be sure this orifice is not clogged and the O-ring and dowel pins are in place before installing the cylinder head.
  • Page 39 5. CYLINDER HEAD/ VALVE CAMSHAFT REMOVAL special bolts NOTE: The camshaft, rocker arm and rocker arm shaft can be serviced with the engine installed on the frame. Remove the 6mm special bolts. Remove the R/L cylinder head side cover and cylinder head side.
  • Page 40 5.INSPECTION/ADJUSTMENT CYLINDER HEAD REMOVAL Remove the 6mm bolts. Remove the dowel pins. Remove cam chain tensioner. Remove the cylinder head. CAM CHAIN GUIDE BOLT Remove the rocker arm shaft. HOLDER Remove the rocker arms.

  • Page 41: Camshaft Inspection

    5. CYLINDER HEAD/ VALVE CAMSHAFT INSPECTION Inspect the cams of the camshaft for wear. Service limit: Inlet: 31.25mm Exhaust: 30.87mm ROCKER ARM INSPECTION Inspect the rocker arm I.D. and the rocker arm for wear, damage or clogged oil holes. Rocker arm I.D. Service limit: ¦...

  • Page 42: Cylinder Head Inspection

    5.INSPECTION/ADJUSTMENT CYLINDER HEAD DISASSEMBIY Remove carbon deposits from the combustion chamber. Remove valve spring and valve spring and valve with a valve spring compressor. CYLINDER HEAD INSPECTION Remove gasket from cylinder head with a scraper. Check the cylinder head for crack. Check the cylinder head for warpage with a straight edge and a feeler gauge.
  • Page 43 5. CYLINDER HEAD/ VALVE VALVE/VALVE GUIDE INSPECTION Inspect valves for scratches, burning or wear. Check the valve movement in the guide. Measure the valve stem O.D. Service limit: Intake: ¡ Ó 5.42mm Exhaust:¡ Ó 5.40mm NOTE: Remove any carbon buildup before checking the valve guide I.D.

  • Page 44: Valve Guide Replacement

    5.INSPECTION/ADJUSTMENT VALVE GUIDE REPLACEMENT Drive out the valve guide from the combustion chamber side with a 5mm valve guide remover. NOTE: When driving out the valve guide, do not damage the cylinder head. Install the new valve guide from the top of the cylinder head, and ream it with a reamer, then clean the cylinder head.
  • Page 45 5. CYLINDER HEAD/ VALVE VALVE SEAT INSPECTION/ REFACING Clean intake and exhaust valves to remove carbon deposits. Apply a light coating of prussian blue to each valve face. Insert each valve into the guide and rotate them two cycles. Remove the valve and inspect the face. CAUTION: If the valve face is burned or damaged or unevenly, replace the valve.
  • Page 46 5.INSPECTION/ADJUSTMENT VALVE SEAT GRINDING 60° NOTE: Follow the instructions described in the cutter instruction manual. 32° 45° Remove any roughness from the seat by applying 4~5 kg pressure, turning the cutter left and right. 4~5kg NOTE: Add engine oil to the face when operating. CUTTER CUTTER HOLDER TURN RIGHT AND LEFT...
  • Page 47 5. CYLINDER HEAD/ VALVE Using a 32 degree cutter, remove 1/4 of the existing valve seat material. CUTTER VALVE SEAT Remove the bottom 1/4 of the old seat by using a 60 degree cutter. CUTTER Finish the seat to the proper width by using a 45 CUTTER degree cutter.
  • Page 48 5.INSPECTION/ADJUSTMENT If the contact area is too high on the valve,the seat must be lowered using a 37.5 degree cutter, then finish CUT TOP END with a 45 degree cutter. CONTACT AREA TOO HIGH If the contact area is too low on the valve,the seat must CONTACT AREA TOO LOW be raised using a 63.5 degree cutter, then finish with a 45 degree cutter.

  • Page 49: Cylinder Head Assembly

    5. CYLINDER HEAD/ VALVE CYLINDER HEAD ASSEMBLY Compress the valve springs with a valve spring compressor and install the valve cotters into the valve retainer. CAUTION: Do not compress the valve spring more than necessary. NOTE: Install a new valve stem seal when assembling. Lubricate each valve stem with the engine oil then insert them into the guides.

  • Page 50: Cylinder Head Installation

    5.INSPECTION/ADJUSTMENT CYLINDER HEAD INSTALLATION CAMSHAFT AND CAMSPROCKET ASSEMBLY NOTE: Rocker arms must be installed at the right position. CAMSHAFT COMP Clean the cylinder head gasket surface of any gasket material. Install the new gasket, O-ring and dowel pins and chain guide. NOTE: Do not allow dust and dirt to enter the cylinder.
  • Page 51 5. CYLINDER HEAD/ VALVE CAM SPROCKET INSTALLATION Rotate the generator rotor and align the "T" mark with the index mark. Install the camshaft comp. When intalling camshaft set, please take care that.The line on the camsprocket should be in parallel with the surface of cylinder head.(The IN/EX cam should be faced down).

  • Page 52: Cylinder/Piston

    6. CYLINDER/PISTON TROUBLE SHOOTING.......6-1 ..6-5 PISTON/PISTON RING INSPECTION SERVICE INFORMATION ....6-2 PISTON RING INSTALLATION..6-7 CYLINDER REMOVAL .......6-3 PISTON INSTALLATION ....6-9 PISTON REMOVAL ......6-4 CYLINDER INSTALLATION ....6-10 TROUBLE SHOOTING LOW COMPRESSION 1. Worn cylinder or piston rings. EXCESSIVE SMOKE 1.
  • Page 53 6.CYLINDER/PISTON SERVICE INFORNATION GENERAL STRUCTIONS NCA250 ITEM STANDARD CERVICE LIMIT Cylinder I.D. 53.005¡ « 53.015mm 53.015mm Cylinder Runout 0.05mm Taper 0.05mm Piston ring to 0.025¡ « 0.055mm 0.13mm ring groove Second 0.015¡ « 0.040mm 0.12mm clearance 0.10¡ « 0.25mm 0.5mm...
  • Page 54 6. CYLINDER/PISTON CAM CHAIN GUIDE CYLINDER REMOVAL Remove the cylinder head. Remove the dowel pins and gasket. Remove the cam chain guide. Remove the cylinder. DOWEL PIN NOTE: Avoid the chain falling into the crankcase during removing the cylinder. CAM CHAIN Remove the dowel pins and gasket.

  • Page 55: Cylinder Inspection

    6.CYLINDER/PISTON CYLINDER INSPECTION Inspect the cylinder bore for wear or damage. Measure the cylinder I.D. NOTE: According to the right picture measure the cylinder runout. Service limit: ITEM NCA250 MIDDLE Runout 0.05mm BOTTOM Taper 0.05mm I.D. 53.015mm PISTON REMOVAL Remove the piston pin clip with pliers.
  • Page 56 6. CYLINDER/PISTON PISTON / PISTON RING INSPECTION Measure the piston ring-to-ring groove clearance. Service limit . Top ring: 0.13mm Second ring: 0.12mm Remove the piston rings. Inspect the piston for damage or cracks. Inspect the piston groove for wear. Insert each piston ring into the cylinder and measure the ring end gap.
  • Page 57 6.CYLINDER/PISTON Measure the piston O.D. at the skirt. Service limit: 52.55mm NOTE: Measure the piston O.D. at a point from the bottom. Calculate the piston-to-cylinder clearance. Service limit:0.11mm Measure the piston pin bore I.D. Service limit:15.07mm Measure the piston pin O.D. Service limit:14.85mm...
  • Page 58 6. CYLINDER/PISTON Measure the top/second ring thickness. Service limit: 1.460mm PISTON RING INSTALLATION TOP RING Install the piston rings. NOTE: SECOND RING Avoid piston and piston ring damage during installation. OIL RING All rings should be installed with the markings facing up.
  • Page 59 6.CYLINDER/PISTON TOP RING SECOND RING OIL RING...

  • Page 60: Piston Installation

    6. CYLINDER/PISTON PISTON INSTALLATION Install the piston, piston pin and piston pin clip. NOTE: Position the "IN" mark on the piston to the carburetor side. Do not let the piston pin clip fall into the crankcase. NOTE: PISTON PIN CLIP Use new piston pin clip whenever disassembling.

  • Page 61: Cylinder Installation

    6.CYLINDER/PISTON CYLINDER INSTALLATION Install the cylinder gasket and dowel pins. Clean the cylinder gasket surface of any gasket material. NOTE: Avoid damaging the cylinder gasket surface during this operation. CAM CHAIN GUIDE Install the cylinder. NOTE: Avoid piston and piston rings damage during installation.

  • Page 62: Clutch/Oil Pump/Gear Shift

    7.CLUTCH/OIL PUMP/GEAR SHIFT TROUBLE SHOOTING.......7-1 OIL PUMP .......... 7-7 SERVICE INFORMATION ....7-2 GEARSHIFT LINKAGE ...... 7-10 .7-3 ..7-12 RIGHT CRANKCASE COVER REMOVAL RIGHT CRANKCASE INSTALLATION CLUTCH ..........7-3 TROUBLE SHOOTING Faulty clutch operation can be corrected by adjusting the clutch lever free play. CLUTCH SPINS WHEN ACCELERATING 1.
  • Page 63 7.CLUTCH/OIL PUMP/GEAR SHIFT SERVICE INFORMATION GENERAL INSTRUCTION This section covers removal, installation and servicing of the clutch, oil pump, filter and gearshift linkage. All these operations can be accomplished with the engine in the frame. COMMON TOOLS 22mm wrench socket Air wrench TORQUE VALUES Right crankcase cover...
  • Page 64 7.CLUTCH/OIL PUMP/GEAR SHIFT RIGHT CRANKCASE COVER REMOVAL Drain oil from the engine. Disconnect the clutch cable. Remove the right crankcase cover. BEARING CLUTCH CLUTCH REMOVAL Remove the clutch bearing. LOCK NUT Remove the 16mm lock nut with the wrench socket and air wrench.
  • Page 65 7.CLUTCH/OIL PUMP/GEAR SHIFT Remove the clutch center, friction disc. clutch plate and pressure plate. CLUTCH CENTER CLUTCH OUTER CLUTCH PLATE CLUTCH PRESSURE PLATE CLUTCH FRICTION DISC INSPECTION Measure the friction discs, replacing them if they are discolored or worn. Service limit: 2.5mm...
  • Page 66 7.CLUTCH/OIL PUMP/GEAR SHIFT CLUTCH PLATE INSPECTION Check the plates for warpage on a surface plate using a feeler gauge. Service limit: 0.2mm CLUTCH SPRING INSPECTION Measure the clutch springs free length. Service limit: 27.9mm CLUTCH OUTER INSPECTION Check the clutch outer for cracks or indentation.
  • Page 67 7.CLUTCH/OIL PUMP/GEAR SHIFT CLUTCH OUTER INSTALLATION Install the clutch outer, 20mm washer. NOTE: When installing the washer, it should fit with the main shaft groove. WASHER Install the clutch pressure plate, friction discs, clutch plates and clutch center. Install and tighten the 16mm lock nut. TORQUE: 500¡...
  • Page 68 7.CLUTCH/OIL PUMP/GEAR SHIFT Install the clutch springs, lifter plate and tighten the bolts. Install the bearing. NOTE: Tighten the bolts in a crisscross pattern in two or three steps. TORQUE :500-700 kgf ¡ ¤ BEARING Install the dowel pins and gasket. Install the right crankcase cover.

  • Page 69: Oil Pump Inspection

    7.CLUTCH/OIL PUMP/GEAR SHIFT Remove the 6mm screws, remove the oil pump. 6mm screws OIL PUMP DISASSEMBLY Remove the oil pump drive gear. Remove the oil pump drive gear and oil pump plate. OIL PUMP INSPECTION Measure the inner-to-outer rotor clearance of the oil pump.

  • Page 70: Oil Pump Assembly

    7.CLUTCH/OIL PUMP/GEAR SHIFT Measure the outer rotor to oil pump body clearance. Service limit: 0.40mm Measure the oil pump upper clearance. Service limit: 0.11mm DRIVE GEAR DRIVE SHAFT OIL PUMP ASSEMBLY Install the inner and outer rotors into the oil pump body. Install the oil pump drive shaft.
  • Page 71 7.CLUTCH/OIL PUMP/GEAR SHIFT Check the oil pump for rotating freely. OIL PUMP INSTALLATION Install a O-rings. Install the oil pump to the right crankcase. O-RING OIL PUMP GEARSHIFT SPINDLE GEARSHIFT LINKAGE GEARSHIFT LINKAGE DISASSEMBLY Remove the clutch (7-3). Remove the gearshift pedal. Remove the gearshift spindle.
  • Page 72 7.CLUTCH/OIL PUMP/GEAR SHIFT Remove the gearshift drum stopper. GEARSHIFT CAM GEARSHIFT DRUM Remove the gearshift cam. STOPPER Check each part for wear or damage. GEARSHIFT LINKAGE ASSEMBLY ROLLER Install the four 10mm rollers. Align the hole of the gearshift cam with the roller, then install the gearshift cam.
  • Page 73 7.CLUTCH/OIL PUMP/GEAR SHIFT Install the gearshift spindle. DRIVE GEAR NOTE : Hook the gearshift return spring on the crankcase abutment. Install the clutch. Install the primary drive gear. Install the oil pump drive gear. Install the drive gear. Install the oil through pin. Install the oil pump.

  • Page 74: A.c. Generator

    8. A.C.GENERATOR TROUBLE SHOOTING ......8-1 ..8-4 LEFT CRANKCASE COVER INSTALLATION ...8-2 STARTER MOTOR REMOVAL ..8-4 LEFT CRANKCASE COVER REMOVAL GENERATOR ROTOR REMOVAL ..8-2 STARTER MOTOR GEAR SET ..8-5 ....8-3 GENERATOR ROTOR INSTALLATION...

  • Page 75: Left Crankcase Cover Removal

    8. A.C.GENERATOR LEFT CRANKCASE COVER REMOVAL Remove the gearshift pedal. Remove the left crankcase rear cover. NOTE: Generator stator is in the left crankcase cover, it can be removed by removing the attaching screws. GENERATOR ROTOR REMOVAL Remove the left crankcase cover. Remove the rotor bolt.

  • Page 76: Generator Rotor Installation

    8. A.C.GENERATOR STATOR INSPECTION Check the stator for continuity. GENERATOR ROTOR INSTALLATION Reverse the procedure of removal to assembly. NOTE : Check wire for security in its place. Do not interfere the wire with the rotor. Install and tighten the rotor. TORQUE: 400~500 kgf ¡...

  • Page 77: Left Crankcase Cover Installation

    8. A.C.GENERATOR LEFT CRANKCASE COVER INSTALLATION Install the left crankcase cover (with stator coil) Connect the generator wire connectors. Route the neutral switch wire through the groove in the left crankcase cover. Install the left crankcase rear cover. Install the gearshift pedal. STARTER MOTOR REMOVAL Disconnect the starter motor wire connector.

  • Page 78: Starter Motor Gear Set

    8. A.C.GENERATOR STARTER MOTOR GEAR SET 1. Starter driven gear 2. Washer 3. Starter reduce gear 4. Starter motor...

  • Page 79: Crankshaft/Crankcase/Transmission

    9.CRANKSHAFT/CRANKCASE/TRANSMISSION TROUBLE SHOOTING.......9-1 TRANSMISSION DISASSEMBLY ..9-6 SERVICE INFORMATION ....9-2 TRANSMISSION ASSEMBLY .... 9-9 CRANKCASE SEPARATION .....9-3 CRANKSHAFT INSTALLATION..9-11 CRANKSHAFT REMOVAL ....9-4 CRANKCASE ASSEMBLY ....9-11 TROUBLE SHOOTING HARD TO SHIFT 1. Shift fork bent 2. Shift fork shaft bent TRANSMISSION JUMPS OUT OF GEAR 1.
  • Page 80 9.CRANKSHAFT/CRANKCASE/TRANSMISSION SERVICE INFORMATION GENERAL INSTRUCTION Transmission and crankshaft repairs require crankcase separation. Remove the following parts before separating the crankcase: Engine removal Cam shaft removal Cylinder / Piston removal Clutch / oil pump / Gearshift linkage removal Left crankcase cover removal SPECIAL TOOLS Bearing driver Bearing driver pilot...
  • Page 81 9.CRANKSHAFT/CRANKCASE/TRANSMISSION CRANKCASE SEPARATION Remove the right crankcover and interial parts. (7-3~ 7-13) Remove left cover and interial parts. Remove the left crankcover all 6mm attaching bolts. Separate the left crankcase from the right crankcase. Remove the gasket and dowel pins.

  • Page 82: Crankshaft Removal

    9.CRANKSHAFT/CRANKCASE/TRANSMISSION CRANKSHAFT REMOVAL CRANKCASE Remove the left crankcase. Remove the crankshaft. CRANKCASE CRANKSHAFT INSPECTION Measure the connecting rod big end side clearance with a feeler gauge. Service limit: 0.60mm FEELER GAUGE Follow the arrow indicated direction to measure the connecting rod big end radial clearance. Service limit:0.05mm...
  • Page 83 9.CRANKSHAFT/CRANKCASE/TRANSMISSION Place the crankshaft on a V-block and measure the runout using a gauge. NOTE: Coat the bearing and connecting rod big end with engine oil before installation. Runout Service limit: 0.01mm Measure the connecting rod small end I.D. Connecting rod small end I.D. Service limit: ¡...

  • Page 84: Transmission Disassembly

    9.CRANKSHAFT/CRANKCASE/TRANSMISSION SHIFT DRUM COUNTER TRANSMISSION SHAFT DISASSEMBLY Remove the crankshaft. Remove the shift fork shaft. Remove the shift drum. Remove the shift forks. MAIN SHAFT SHIFT FORK SHIFT FORK SHAFT SHIFT DRUM SHIFT FORK AND SHIFT FORK SHAFT INSPECTION Check the shift fork for wear, bending or damage. Measure the shift fork I.D.
  • Page 85 9.CRANKSHAFT/CRANKCASE/TRANSMISSION Measure the shift fork shaft O.D. Service limit: 11.976mm SHIFT DRUM INSPECTION Check the gearshift drum for wear or damage. Disassemble the transmission gears. Check each gear for wear or damage and replace if necessary.
  • Page 86 9.CRANKSHAFT/CRANKCASE/TRANSMISSION Check the crankcase oil orifice for clogged, blowing through with compressing air if necessary. Check the crankcase bearings, replace them if they have excessive free play or noisy. FREE PLAY FREE PLAY AXIAL RADIAL BEARING INSTALLATION Install the bearings into the left, right crankcase with special tools.

  • Page 87: Transmission Assembly

    9.CRANKSHAFT/CRANKCASE/TRANSMISSION TRANSMISSION ASSEMBLY NOTE: Before assembling,coat each gears with engine oil. Counter shaft Main shaft Driver sprocket Assemble the gears of the countershaft and mainshaft. NOTE: Seat the snap ring in the ring groove properly.
  • Page 88 9.CRANKSHAFT/CRANKCASE/TRANSMISSION OIL PLATE Install the oil plate comp in the right crankcase. CRANKSHAFT Install the crankshaft assemblies in the right crankcase. Install the mainshaft and countershaft MAINSHAFT assemblies in the right crankcase. NOTE: Keep the thrust washers in place during installation. COUNTERSHAFT Install the mainshaft, countershaft and shift forks.
  • Page 89 9.CRANKSHAFT/CRANKCASE/TRANSMISSION Install the gearshift drum. GEARSHIFT DRUM Install the shift fork shaft. NOTE Engage the shift fork guide pin with the drum groove by raising the shift fork. After assembling, check each part for moving freely. SHIFT FORK SHAFT CRANK CASE ASSEMBLY Install the gasket and dowel pins.

  • Page 90: Carburetor

    10. CARBURETOR TROUBLE SHOOTING.......10-2 ..10-6 FLOAT/FLOAT VALVE/JETS ASSEMBLY SERVICE INFORMATION ....10-2 FLOAT/LEVEL ADJUSTMENT... 10-6 CARBURETOR REMOVAL ....10-3 THROTTLE VALVE ASSEMBLY..10-6 THROTTLE VALVE DISASSEMBLY ..10-3 CARBURETOR INSTALLATION ..10-7 10-4 FLOAT/FLOAT VALVE/JETS DISASSEMBLY 10-1...
  • Page 91 10. CARBURETOR TROUBLE SHOOTING ENGINE CRANKS BUT NOT START 1. No fuel in the fuel tank 2. No fuel in the carburetor 3. Too much fuel in the combustion chamber 4. No spark at the spark plug ( ignition malfunction ) 5.

  • Page 92: Carburetor Removal

    10. CARBURETOR CARBURETOR CARBURETOR REMOVAL PROTECT COVER Disconnect the fuel line. Disconnect the all connect tubes. Drain fuel from the carburetor. WARNING: Keep away from flames or sparks. Wipe up spilled gasoline at once. CARBURETOR Loosen the carburetor band. BAND BAND THROTTLE VALVE DISASSEMBLY...
  • Page 93 10. CARBURETOR Remove the carburetor assembly. jet needle spring VACUUM CHAMBER DISASSEMBLE Remove the two screws and remove the vacuum chamber cover. Remove the piston spring. Remove the needle holder, jet needle spring, jet needle and vacuum piston. WARNING: Avoid damage to the vacuum membrane. jet needle vacuum piston Needle holder...
  • Page 94 10. CARBURETOR FLOAT/FLOAT VALVE/JETS DISASSEMBLE Remove the float chamber body. float chamber WARNING: Pour the float chamber gasoline into the tank. Pull out the float pin, remove the float and float valve. float valve float float pin FLOAT VALVE INSPECTION WEAR OR DAMAGE Inspect the float valve surface for wear or damage.
  • Page 95 10. CARBURETOR Remove the main jet, main jet holder and slow jet. NOTE: Avoid damage to the jets. main jet slow jet main jet main jet holder Remove the air screw. air screw NOTE Before removing air screw, record the number of relations until it rests lightly,so it can be returned to its original position.
  • Page 96 10. CARBURETOR FLOAT/FLOAT VALVE/JETS ASSEMBLY Install the stop screw, the main jet, main jet holder and slow jet. NOTE: Do not damage jets at the time of assembly. FLOAT LEVEL ADJUSTMENT If the float level is too high or too low,bend the float arm for adjusting.

  • Page 97: Carburetor Installation

    10. CARBURETOR Connect the throttle cable. NOTE: Make sure that the throttle cable is pulled tightly. throttle cable CARBURETOR INSTALLATION Reverse the procedure of removal to install the carburetor. Then adjust the followings: Throttle grip free play (2-10). Idling speed (2-11). 10-8...

  • Page 98: Ignition System

    14. IGNITION SYSTEM TROUBLE SHOOTING.......14-1 IGNITION COIL ........14-3 SERVICE INFORMATION ....14-2 TROUBLE SHOOTING ENGINE CRANKS BUT NOT START 1. No sparks at the spark plug 2. Improper ignition timing 3. Faulty plug NO SPARKS AT THE SPARK PLUG Black/white Black/red 1.
  • Page 99 14. IGNITION SYSTEM SERVICE INFORMATION GENERAL INSTRUCTION This section contains the ignition system. Be sure that the battery is fully charged before diagnosing troubles in the ignition system. Also refer to the following pages: Spark plug Ignition timing adjustment SPECIFICATIONS Spark plug: A6RTC Spark plug gap:...
  • Page 100 14. IGNITION SYSTEM IGNITION COIL IGNITION COIL IGNITION COIL REMOVAL Remove the seat. Remove the fuel tank. Disconnect all wires to the ignition coil. Remove the ignition coil. IGNITION COIL TEST Check the ignition coil output using a tripolar tester. NOTE: Follow the instructions described in the user manual.

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