SANYANG INDUSTRY CO. XS125-K Service Manual Download Page 45

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CYLINDER HEAD/

VALVE

5-9

VALVE SEAT INSPECTION/ REFACING

Clean in

take 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.

Inspect the valve seat.
If the seat is too wide or too narrow, the seat must be
refinished.

VALVE SEAT

CONTACT AREA

SERVICE LIMIT

1.5mm

SERVICE LIMIT

1.8mm

Summary of Contents for XS125-K

Page 1: ...SERVICE MANUAL XS 125 K DK Version 1 0 2009 ...

Page 2: ...the SANYANG XS125 K l All information illustrations directions and specifications included in this publication are base on SANYANG XS125 K l SANYANG reserves the right to make changes at any time without notice and without incurring any obligation whatever SANYANG INDUSTRY CO LTD SERVICE DIVISION ...

Page 3: ...TALLATION 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 4: ...ts and lubricants or those equivalent When parts are to be reused they must be inspected carefully to make sure they are not damaged or deteriorated and in good usable condition 7 Upon assembling check every possible part for proper installation and movement or operation 4 Use special tool when use of such a tool is specified 8 Work safely and give your work your undivided attention Exchange signa...

Page 5: ... Single cylinder 15 inclinde from vertical Bore stroke 56 5 x49 5mm Displacement 124 1c c Compression ratio 9 0 1 Oil capacity 0 80 0 95liter 0 9 liter for change opens 5 BTDC Intake valve closes 35 ABDC opens 30 BBDC Exhaust valve closes 5 ATDC IN 0 10mm Valve clearance EX 0 15mm ENGINE Idle speed 1400 100 rpm Clutch Wet muti plate type Transmission 5 speed internationl Primary reduction ratio 4 ...

Page 6: ...80 320 280 320 400 500 80 120 80 120 80 120 80 120 40 50 40 70 FRAME TIGHTEN LOCATION Q TY THREAD DIA mm TORQUE kgf cm Front wheel axle nut Rear wheel axle nut Rear fork pivot nut Engine upper hanger nut Engine front hanger nut Handle pipe upper holder bolt Steering stem nut Front fork nut Rear shock absorber Rear brake torque link Front fork top bridge Front fork bottom bridge Final drive sprocke...

Page 7: ...nd carburetor clogged float chamber fuel tube clogged gasoline cover air hole clogged fuel filter clogged fuel filter screen clogged gasoline auto fuel cup faulty spark plug faulty fouled spark plug CDI unit fualty pulse coil faulty high voltage coil cable open or short high voltage coil open or short main switch faulty A C G faulty Battery faulty valve too tight no gap valve seat faulty cylinder ...

Page 8: ... C Generator fualty valve seat cylinder piston worn gasket leak valve timing incorrect piston ring worn remove and clean remove dirt spark plug improper heat range spark plug clearance misadjustment no fouled discolored dirt and color change valve clearance misadjustment valve seat worn check crankcase oil level for too much or dirt oil lever normal oil too much too much oil too little oil oil no ...

Page 9: ... loosen screw rich mixture tighten screw no air inlet has air inlet carburetor gasket has air inlet insulator plate gasket poor carburetor locking nut loose insulator plate gasket torn vacuum tube crack Remove spark plug insert to the plugcap check spark by toucning engine irongrid sparking well poor sparking poor or dirty spark plug faulty CDI unit faulty A C Genertor poor ignition coil spark plu...

Page 10: ...or adjustment valve seat faulty normal abnormal check auto fuel cup for fuel supplied too little fuel in the fuel tank fuel tube fuel filter clogged air hole on the fuel tank colgs auto fuel cup faulty no blocked blocked valve timing adjusting inspection timing correct timing incorrect cam sprocket aligning marks incorrect carburetor blocked check valve spring clean good spring broken loose elasti...

Page 11: ...age red wire and frame body grounding with mult meter terminals normal abnormal after engine starter measure the voltage between voltage regulaton rectifier red wire and green wire connected with frame body voltage over normal voltage normal measure the resistance of AC generator coil check voltage regulator rectifier coupler for poor contact coil faulty connector poor contact AC generator white w...

Page 12: ...park plug cap slack check CDI unit plug for slack normal abnormal plug poor contact Check the resistance between the wires terminals of CDI unit normal abnormal Check related portions normal abnormal use CDI tester for CDI unit normal abnormal use CDI tester to check ignition voltage coil abnormal fualty main switch faulty trigger magntic coil faulty CDI unit faulty IGN coil control cable open con...

Page 13: ... TEST 2 6 VALVE CLEARANCE 2 7 IGNITION TIMING 2 8 CAM CHAIN TENSION ADJUSTMENT 2 9 THROTTLE GRIP ADJUSTMENT 2 10 IDLING SPEED ADJUSTMENT 2 11 FRAME AIR CLEANER 2 12 CLUTCH ADJUSTMENT 2 12 BRAKE ADJUSTMENT 2 13 DRIVE CHAIN ADJUSTMENT 2 14 WHEELS RIM 2 15 SUSPENSION 2 16 STEERING 2 17 BATTERY 2 17 HEAD LIGHT AIM 2 18 STOPLIGHT SWITCH 2 18 ...

Page 14: ... bearing L L 17 Variomatic components I I 18 Fuel cock og hoses I I I 19 Fuel filter I R R 20 Throttle function and cable A A A 21 Bolts and nuts engine I I 22 Bolts and nuts chassis I I 23 Head cylinder and piston I I 24 Exhaust system I I I 25 Cam chain I I I 26 Valve clearance A A A 27 Front fork inner tubes C L C L C L 28 Suspension front and rear I I I 29 Main side stand I I L I L 30 Speedome...

Page 15: ...er free play 10 20mm Drive chain stack 10 20mm Front brake lever free play 10 20mm Rear brake pedal free play 20 30mm Throttle grip free play 2 6mm SPECIAL TOOL Valve clearance adjuster TORQUE VALVES Right crankcase cover 80 120 kgf cm Front fork top bridge bolt 100 140 kgf cm Front fork bottom bridge bolt 200 250 kgf cm Rear wheel axle nut 400 550 kgf cm Rear shock absorber nut 300 400 kgf cm Rea...

Page 16: ...l the crankcase to the upper level mark with the recommended grade oil OIL REPLACEMENT NOTE Remove the oil filter screen cover and drain the engine oil NOTE Always replace the oil filter screen cover O ring when disassembled Fill the crankcase up to the upper level mark on the oil level gauge with the recommended oil 10W 40 LIQUI MOLY Racing 4T 10W 40 API SL Drain the engine oil while the engine i...

Page 17: ...spark plug cap and remove the spark plug Visually inspect the spark plug electrodes for wear The center electrode should have square edges and side electrode should have a constant thickness Discard the spark plug if there is apparent wear or if the insulator is cracked and or chipped If the spark plug deposits can be removed by sandblasting or wire brushing the spark plug can be reused Inspect th...

Page 18: ...c 1kg c Low compression can be caused by Ÿ Improper calve adjustment Ÿ Valve leakage Ÿ Blown cylinder head gasket Ÿ Worn piston rings or cylinder Ÿ Worn piston High compression can be caused by Ÿ Carbon deposits in combustion chamber or on piston head Ÿ Watch for compression leaking at the gauge connection Ÿ Crank the engine until the gauge reading stops rising The maximum reading is usually reach...

Page 19: ...compression stroke Inspect the intake and exhaust valve clearance by inserting a feeler gauge between the adjusting screw and valve stem valve clearance Intake 0 10mm Exhaust 0 15mm Adjust by loosening the lock nut and turning the adjusting screw until there is a slight drag in the feeler gauge NOTE Inspect and adjust the valve clearance while the engine is cold Inspect the valve clearance again a...

Page 20: ...ion timing with a timing light Timing is correct if the index mark aligns with the F mark within 3 at 1500rpm Ignition timing 10 BTDC 1500rpm Ignition coil continuity test Check the resistance of the primary coil and secondary coil 1 Primary coil 0 31 0 03Ω 2 Secondary coil 4 0 0 4kΩ Check the O ring for damage and spread oil before installing the caps The C D I ignition timing is not adjustable I...

Page 21: ...EXT 4 ONI 5 ONZ no sparks no sparks no sparks sparks sparks sparks no sparks no sparks CAM CHAIN TENSIONER ADJUESTER The cam chain tension is kept by the tensioner push rod that is compressed by the spring CAUTION If remove any parts that is related with the cam chain remove the cam chain tensioner adjuester first CAM CHAIN TENSIONER ADJUESTER ...

Page 22: ...2 INSPECTION ADJUSTMENT 2 10 CARBURETOR THROTTLE GRIP FREE PLAY Check throttle grip free play Free play 2 6mm THROTTLE GRIP ADJUSTMENT Loosen the lock nut and turn the adjuster to adjust ADJUSTER NUT ...

Page 23: ...crew 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 100 rpm NOTE Turn the air screw clockwise for making fuel air mixture lean Turn counterclockwise for rich STOP SCREW AIR SCREW ...

Page 24: ... the air cleaner element NOTE Clean the cleaner element periodically Refer to maintenance schedule Assemble air cleaner element in reverse order of disassemble CLUTCH ADJUSTMENT CLUTCH LEVER FREE PLAY Measure the clutch free play at the tip of the clutch lever Free play 10 20mm SCREWS AIR CLEANER ELEMENT ...

Page 25: ...T FRONT BRAKE LEVER FREE PLAY Measure the brake free play at the tip of the brake lever Free play 10 20mm BRAKE PAD WEAR INSPECTION Check for brake pad wear by operating the bake lever Check the brake pads for wear by looking through the slot indicated by the arrow cast on the caliper assembly Replace the brake pads if the wear line on the pads reaches the edge of the brake disc ADJUSTER NUT LOCK ...

Page 26: ...ckwise to decrease the free play and counterclockwise to increase the play CAUTION The adjuster nuts indentation should seat against the brake arm pin properly DRIVE CHAIN ADJUSTMENT Place the motorcycle on its main stand and shift the transmission into neutral Remove chain cap and check the drive chain slack by moving up and down with the fingers Chain slack 10 20mm 20 30mm 10 20m m ADJUSTING NUT...

Page 27: ...slack and free wheel rotation Lubricate the drive chain with chain lubricant WHEEL RIM Stand the motorcycle check the tires for cuts imbedded nails or other sharp objects Check the tire pressure One rider Front 2 25 kg c Rear 2 50 kg c Cold tire Two riders pressure Front 2 50 kg c Rear 2 50 kg c Max load 120kg Tire size Front 2 75 18 Rear 90 90 15 Min depth of tread Front 1 5mm Rear 2 0mm ADJUSTIN...

Page 28: ...en them to the specified torque TORQUE Front fork top bridge bolt 100 140 kgf cm Frint fork bottom bridge bolt 240 300 kgf cm Axle nut 600 800 kgf cm REAR SUSPENSION Check for abnormal noises and leaks by compressing the rear suspension several times Check the rear suspension nut for loosing Torque 300 400 kgf cm Move the rear wheel side ways with force to see if the swing arm bushings are worn Re...

Page 29: ...e battery fluid level if the fluid level nears the lower level mark fill with distilled water to the upper level mark Clean the battery terminals with warm water Check the specific gravity of the battery electrolyte 13 3 NOTE Do not overfill Add only distilled water Tap water will shorten the service life of the battery WARNING Keep the electrolyte away from eyes skin and clothes If touched it was...

Page 30: ...he headlight bolts loosening Fasten the bolts after adjustment 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 ADJUST NUTS STOPLIGHT SWITCH ADJUSTING NUT ...

Page 31: ...3 LUBRICATION SYSTEM 3 0 CAM SHAFT OIL LINE OF CAM SHAFT PISTON OIL FILTER OIL ORIFICE OF CRANKSHAFT OIL PUMP MAIN SHAFT COUNTER SHAFT ...

Page 32: ...l filter clogged 2 Oil pump damaged OIL PRESSURE TOO HIGH 1 Oil filter or line clogged 2 Oil not recommended NO OIL PRESSURE 1 Oil level too Iow 2 Oil pump damaged SERVICE INFORMATION NOTICE Inspection and service of oil pump can be serviced with the engine installed on the frame Oil pump service 7 9 Oil filter cleaning 2 4 2 5 SPECIFICATIONS Oil capacity Oil recommended Oil pump delivery 0 85 0 9...

Page 33: ...arm Ÿ Shift spindle Ÿ Cam chain tensioner Ÿ Kick starter arm The following parts must be serviced with the engine removed off the frame Ÿ Cylinder head Ÿ Cylinder Ÿ Piston Ÿ Crankshaft Ÿ Transmission Ÿ Kick starter shift During removal and installation jack or adjustable support is required to maneuver the engine TORQUE VALUES Engine hanger 10mm bolt nut 450 550 kgf cm Drain bolt 300 500 kgf cm Ge...

Page 34: ...he fuel tubes and all connect tubes Remove the right and left side covers Remove the gear change pedal and left crank case rear cover Disconnect the A C generator wire of the connector and remove the generator wire Remove the wire clamp screw and clamp A C GENERATOR WIRE LEFT CRANKCASE RR COVER GEAR CHANGE PEDAL ...

Page 35: ...arate the carburetor pipe and the cylinder head by removing the attaching bolts Remove the crankcase breather tube Loosen the rear wheel axle nut Loosen the drive chain adjusting nut and push the rear wheel forward Remove the drive chain clip and remove the drive chain CLIP BREATHER TUBE CLUTCH CABLE WHEEL AXLE NUT ADJUSTING NUT ...

Page 36: ...ge to wire harnesses and cables during operation ENGINE INSTALLATION Follow the reverse procedure of removal to install the engine Notice the following items during installation Ÿ Route all wire harnesses and cables properly Ÿ Adjust the throttle grip free play P2 10 Ÿ Adjust the clutch lever free play P2 12 Ÿ Adjust the drive chain slack P2 14 Ÿ Fill the crankcase with the recommended grade oil t...

Page 37: ...DER HEAD INSTALLATION 5 14 CAM SHAFT INSTALLATION 5 15 TROUBLE SHOOTING LOW COMPRESSION 1 Valve Incorrect valve clearance Burned or bent valves Incorrect valve timing Broken valve spring 2 Cylinder head Leaking or damaged head gasket Warped or cranked cylinder head HIGH COMPRESSION 1 Excessive carbon buildup on piston or combustion chamber ABNORMAL NOISE I Incorrect valve clearance 2 Broken valve ...

Page 38: ...QUE VALUES Cylinder head bolt 280 300 kgf cm Cylinder 6mm bolt 140 180 kgf cm Cam sprocket 80 120 kgf cm SPEClFICATIONS ITEM STANDARD SERVICE LIMIT IN 32 382mm 31 25mm below Cam lift EX 31 987mm 30 87mmbelow Camshaft Runout 0 02mm Rocker arm I D I D 12 000 12 018mm 12 018mm above Rocker arm shaft O D 11 966 11 984 mm 11 966mm below Free length 39 95 40 55mm 39mm below Valve spring Stall length 36 ...

Page 39: ... hole cap and the timing inspection hole cap Rotate the generator rotor counterclockwise and locate the piston at the T D C of the compressing stroke Remove the cam sprocket bolts and remove the cam sprocket NOTE Take care not to drop then bolt into the crankcase Suspend the cam chain with a wire to prevent it from falling into the crankcase Remove the camshaft INDEX MARK O MARK CAM SPROCKET COVER...

Page 40: ...AL Remove the cam chain tensioner bolt Remove the 8mm bolt Remove the 4 cylinder head nuts Remove the dowel pins Remove cam chain tensioner Remove the cylinder head Remove the rocker arm shaft Remove the rocker arms CAM CHAIN TENSIONER BOLT 8mm BOLT ...

Page 41: ... 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 φ12 018mm ROCKER ARM SHAFT INSPECTION Inspect rocker arm shaft for wear or damage Rocker arm shaft O D Service limit φ11 966mm ...

Page 42: ... 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 Service limit 0 10mm VALVE SPRING INSPECTION Measure the free length of the inner and outer valve spring Service limit 39mm below SPRING RETAINER VALVE COTTER VALVE ...

Page 43: ... Exhaust 5 40mm NOTE Guide I D service limit Intake 5 50mm Exhaust 5 50mm Measure the valve guide I D and calculate the stem to guide clearance Service limit Intake 0 08mm Exhaust 0 10mm If the stem to guide clearance exceeds the service limit replace the valve or guide to fit NOTE Remove any carbon buildup before checking the valve guide I D The guide must be reamed when replacing a new one ...

Page 44: ...uide 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 VALVE GUODE REMOVER ...

Page 45: ...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 Inspect the valve seat If the seat is too wide or too narrow the seat must be refinished VALVE SEAT CONTACT AREA SERVICE LIMIT 1 5mm SERVICE LIMIT 1 8mm ...

Page 46: ... instruction manual Remove any roughness from the seat by applying 4 5 kg pressure turning the cutter left and right NOTE Add engine oil to the face when operating Using a 45 degree cutter remove any roughness from the seat 4 5kg CUTTER HOLDER TURN RIGHT AND LEFT CUTTER ROUGHNESS VALVE SEAT 45 45 32 60 ...

Page 47: ...2 degree cutter remove 1 4 of the existing valve seat material Remove the bottom 1 4 of the old seat by using a 60 degree cutter Finish the seat to the proper width by using a 45 degree cutter 32 o CUTTER VALVE SEAT 60o CUTTER 45o CUTTER ...

Page 48: ...sh with a 45 degree cutter If the contact area is too low on the valve the seat must be raised using a 63 5 degree cutter then finish with a 45 degree cutter After cutting the seat apply lapping compound to the valve face and lap the valve using light pressure CONTACT AREA TOO HIGH CUT TOP END CUT BOTTOM END CONTACT AREA TOO LOW 63 5 o ...

Page 49: ...ve 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 Install the valve spring and retainers NOTE Install the valve springs with the tightly wound coils facing the cylinder head Tap the valve stems gently with a plastic hammer to firmly seat the cotters SPRING RETAINER VALVE COTTER VALVE ...

Page 50: ...r 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 Install the cylinder head NOTE Support the cam chain to keep it from falling into the crankcase Install the cam chain tensioner set and bolt and washer Install dowel pins ROCKER ARM TENSIONER BOLT 8mm BOLT ...

Page 51: ...lder Install the cylinder head nuts TORQUE 280 300 kgf cm CAUTION The cap nut of the four holder nuts must be installed at the left front side Install the 6mm bolts Install the cam chain chain tensioner Install the auto tensioner Lock the spring cap bolt first Release the auto tensioner lock bolt Adjust the valve clearance 2 7 Install the cylinder head cover Install the R L cylinder head side cove...

Page 52: ...L NOISE 1 Worn piston or cylinder 2 Excessive carbon build up SERVICE INFORNATION GENERAL STRUCTIONS XS125 K ITEM STANDARD CERVICE LIMIT Cylinder I D 56 495 56 515mm 56 52mm Runout 0 05mm 0 05mm Cylinder Taper 0 05mm 0 05mm Top 0 025 0 055mm 0 060mm Piston ring to ring groove clearance Second 0 015 0 040mm 0 045mm Top 0 10 0 30mm 0 5mm Second 0 10 0 30mm 0 5mm Piston ring End gap Oil ring 0 30 0 9...

Page 53: ...e cylinder Remove the dowel pins and gasket Clean the cylinder gasket surface of any gasket material NOTE Avoid damaging the cylinder gasket surface during this operation 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 XS125 K Runout 0 05mm Taper 0 05mm I D 56 52mm ...

Page 54: ...p falling into the crankcase 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 Top Second ring 0 5mm ...

Page 55: ...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 05mm Measure the piston pin O D Service limit 14 994mm Measure the top second ring thickness Service limit 1 460mm ...

Page 56: ...ston ring end gaps 120 degree apart Ÿ Avoid piston and piston ring damage during installation Ÿ All rings should be installed with the markings facing up Ÿ After installation the piston rings should be free to rotate in the grooves TOP RING SECOND RING OIL RING TOP RING SECOND RING OIL RING ...

Page 57: ...clip end gap with the piston cutout 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 Install the cylinder NOTE Avoid piston and piston rings damage during installation Install the cylinder gasket and dowel pins Install the cylinder head 5 8 NOTE Coat the cy...

Page 58: ... T RETURN 1 Return spring broken or weak 2 Shift spindle bent JUMPS OUT OF GEAR 1 Stopper arm spring broken LOW OIL PRESSURE 1 Oil pump drive gear worn 2 Faulty oil pump 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 ...

Page 59: ...t the clutch cable Remove the kick starter arm Remove the right crankcase cover CLUTCH CLUTCH REMOVAL Remove the clutch lifter rod Remove the oil filter rotor cover Remove the 16mm lock nut with a lock nut wrench Remove the oil filter rotor LIFTER ROD CLUTCH CABLE FILTER ROTOR COVER OIL FILTER ROTOR ...

Page 60: ...utch bolt clutch lifter plate and clutch spring CLUTCH SPRING INSPECTION Measure the clutch springs free length Service limit 28 6mm Remove the 20mm set ring Remove the clutch center disks plates and pressure plate SET RING CLUTCH LIFTER PLATE CLUTCH BOLT ...

Page 61: ...tch disks if they have any score or discoloration Measure the clutch friction disk thickness SERVICE LIMIT 2 8mm CLUTCH PLATE INSPECTION Check the plates for warpage on a surface plate using a feeler gauge Service limit 0 2mm CLUTCH CENTER CLUTCH OUTER CLUTCH PLATE CLUTCH PRESSURE ...

Page 62: ...heck the clutch outer for cracks or indentation CLUTCH OUTER INSTALLATION Install the clutch outer 20mm washer on the main shaft NOTE When installing the washer it should fit with the main shaft groove Install the clutch pressure plate friction discs clutch plates and clutch center WASHER 20mm WASHER ...

Page 63: ...ock washer and 16mm lock nut Tighten the 16mm lock nut TORQUE 400 500 kgf cm Install the filter rotor cover Check the oil through for a smooth operation without binding Install the lifter rod Install the dowel pins and a new gasket Install the right crankcase cover Connect the clutch cable Install the exhaust muffler and step bar Fill the crankcase with the recommended oil Adjust the clutch lever ...

Page 64: ... oil filter rotor Remove the oil pump cover Remove the oil pump drive gear Remove the 6 mm screws and oil pump OIL PUMP DISASSEMBLY Remove the oil pump plate OIL PUMP INSPECTION Measure the inner rotor to outer rotor clearance SERVICE LIMIT 0 35mm OIL PUMP OIL PUMP DRIVE GEAR 6mm SCREWS OIL PUMP PLATE ...

Page 65: ...TE Service limit 0 11mm OIL PUMP ASSEMBLY Install the oil pump drive gear and gear shaft on the pump body Install the oil pump cover NOTE Align the cutout in inner rotor with the cutout on the shaft Check the oil pump for rotating freely DRIVE SHAFT OIL PUMP COVER DRIVE GEAR OIL PUMP BODY Measure the clearance with the gasket installed ...

Page 66: ... PUMP INSTALLATION Install new O rings Install the oil pump to the right crankcase GEARSHIFT LINKAGE GEARSHIFT LINKAGE DISASSEMBLY Remove the clutch Remove the gearshift pedal Remove the gearshift spindle OIL PUMP O RING GEARSHIFT SPINDLE ...

Page 67: ...T LINKAGE ASSEMBLY Install the four 4mm roller Align the hole of the gearshift cam with the roller then install the gearshift cam Install the gearshift drum stopper NOTE After installation check the drum stopper operation GEARSHIFT CAM GEARSHIFT DRUM STOPPER ARM 4MM ROLLER GEARSHIFT CAM GEARSHIFT SPINDLE GEARSHIFT CAM GEARSHIFT DRUM STOPPER ...

Page 68: ...ge for smooth operation Install the clutch oil pump and oil filter rotor RIGHT CRANKCASE COVER INSTALLATION Install the dowel pins and a new gasket Install the right crankcase cover and tighten the screws Connect the clutch cable Install the kick starter pedal Fill the crankcase with the recommended oil Adjust the clutch lever free play OIL PUMP CLUTCH DRIVE GEAR ...

Page 69: ...LATION 8 3 STARTER MOTOR REMOVAL 8 4 STARTER DRIVEN GEAR REMOVAL 8 4 STARTER MOTOR GEAR SET 8 4 SERVIE INFORMATION GENERAL INSTRUCTION This section covers removal and installation of the AC generator and starter motor These operation can be done with the engine installed in the frame Special tool Rotor puller TORQUE VALVE Flywheel bolt 260 320kgf cm ...

Page 70: ...r and pulse generator wire connector Remove the left crankcase cover NOTE Generator stator is in the left crankcase cover it can be removed by removing the attaching screws FLYWHEEL REMOVAL Remove the flywheel bolt Remove the flywheel with the rotor puller FLYWHEEL SETTING BOLT GEARSHIFT PEDAL LEFT CRANKCASE REAR COVER LEFT CRANKCASE COVER ...

Page 71: ...lse generator assembly if necessary FLYWHEEL INSTALLATION Reverse the procedure of removal to assembly NOTE Ÿ Check wire for security in its place Ÿ Do not interfere the wire with the flywheel Install and tighten the flywheel TORQUE 400 500 kgf cm LEFT CRANKCASE COVER INSTALLATION Install the left crankcase cover with stator coil Connect the generator wire connectors Route the neutral switch wire ...

Page 72: ...IVEN GEAR REMOVAL Remove the left crankcase cover Remove the flywheel Remove the starter driven gear STARTER MOTOR GEAR SET 1 Starter driven gear 2 Starter reduce gear 3 Starter motor Install the starter motor and gear in the reverse order of removal ELECTRIC CONNECTOR STARTER DRIVEN GEAR BOLTS STARTER DRIVEN GEAR STARTER REDUCE GEAR STARTER MOTOR ...

Page 73: ...sion gears 2 Worn spline shafts SERVICE INFORMATION GENERAL INSTRUCTION Transmission and crankshaft repairs require crankcase separation Remove the following parts before separating the crankcase Engine removal 4 2 Cylinder head removal 5 2 Cylinder Piston removal 6 2 Clutch oil pump Gearshift linkage removal 7 2 Left crankcase cover removal 8 2 Flywheel removal 8 2 SPECIAL TOOLS Bearing driver Be...

Page 74: ...9 CAMSHAFT CRANKSHAFT CRANKCASE TRANSMISSION KICKSTARTER 9 2 CRANKCASE SEPARATION Remove the right crankcover and interial parts 7 3 7 13 Remove left cover and interial parts ...

Page 75: ...kcase from the right crankcase Remove the gasket and dowel pins CRANKSHAFT REMOVAL Remove the left crankcase Remove the crankshaft CRANKSHAFT INSPECTION Measure the connecting rod big end side clearance with a feeler gauge Service limit 0 60mm Measure the connecting rod big end radial clearance Service limit 0 05mm CRANKCASE CRANKCASE ...

Page 76: ...ng and connecting rod big end with engine oil before installation Service limit 0 050mm Measure the connecting rod small end I D Connecting rod small end I D Service limit 15 08mm CRANKSHAFT BEARING INSPECTION Spin the crankshaft bearing by hand and check for play The bearing must be replaced if it is noisy or has excessive play FREE PLAY FREE PLAY AXIAL RADIAL ...

Page 77: ...hift drum Remove the shift forks SHIFT FORK AND SHIFT FORK SHAFT INSPECTION Check the shift fork for wear bending or damage Measure the shift fork I D Service limit 12 05mm Measure each shift fork claw thickness Service limit 4 80mm CHECK FOR WEAR OR DAMAGE SHIFT FORK SHAFT SHIFT FORK SHIFT DRUM MAIN SHAFT COUNTER SHAFT SHIFT DRUM SHIFT FORK SHAFT ...

Page 78: ...haft 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 Check the crankcase oil orifice for clogged blowing through with compressing air if necessary ...

Page 79: ...k the crankcase bearings replace them if they have excessive free play or noisy BEARING INSTALLATION Install the bearings into the left right crankcase with special tools NOTE Install the bearing horizontally to prevent bearing damage FREE PLAY FREE PLAY AXIAL RADIAL ...

Page 80: ... 9 8 TRANSMISSION ASSEMBLY NOTE Before assembling coat each gears with engine oil Assemble the gears of the countershaft and mainshaft NOTE Seat the snap ring in the ring groove properly Counter shaft Main shaft C1 C3 C4 C5 C5 Driver sprocket C2 M2 M5 M4 M3 ...

Page 81: ...ight crankcase NOTE Keep the thrust washers in place during installation Install the mainshaft countershaft and shift forks Install the 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 CRANKSHAFT MAINSHAFT SHIFT FORK SHAFT GEARSHIFT DRUM SHIFT FORK ...

Page 82: ...SSEMBLY Remove the kick starter spindle assembly Remove the kick starter spindle from the engine Remove the thrust washer and drive ratchet Measure the I D of the pinion Service limit 24 96mm Measure the pinion sliding O D of the spindle Service limit 24 80mm KICK STARTER SPINDLE ...

Page 83: ...SSION KICKSTARTER 9 11 KICK STARTER ASSEMBLY Reverse the operation of diassembly for assembing CRANK CASE ASSEMBLY Install the gasket and dowel pins Install the left crankcase on the right crankcase NOTE Make sure that the gasket is in place ...

Page 84: ...r clogged ENGINE IDLE ROUGHLY 1 Idling speed incorrect 2 Ignition malfunction 3 Low compression 4 Rich mixture 5 Lean mixture 6 Air cleaner clogged 7 Air leaking into intake pipe 8 Fuel contaminated LEAN MIXTURE 1 Carburetor jets clogged 2 Float chamber vent clogged 3 Fuel filter clogged 4 Fuel line restricted 5 Float level too Iow 6 Float valve faulty RICH MIXTURE 1 Choke stuck closed 2 Float val...

Page 85: ...carburetor WARNING Keep away from flames or sparks Wipe up spilled gasoline at once Loosen the carburetor band THROTTLE VALVE DISASSEMBLY Disconnect the throttle cable Remove the needle spring Remove the needle Check the needle and throttle valve for wear or damage CARBURETOR BAND THROTTLE CABLE NEEDLE SPRING NEEDLE ...

Page 86: ... JETS DISASSEMBLE Remove the float chamber body WARNING Pour the float chamber gasoline into the tank Pull out the float pin remove the float and float valve FLOAT VALVE INSPECTION inspect the float valve surface for wear or damage WEAR OR DAMAGE FLOAT PIN FLOAT VALVE ...

Page 87: ...e to the jets Remove the air screw NOTE Before removeing air screw record the number of relations until it rests lightly so it can be returned to its original position Check each part for damage Blow open all body openings with compressed air MAIN JET NEEDLE JET NEEDLE JET HOLDER AIR SCREW ...

Page 88: ... jet and needle jet holder NOTE Do not damage jets at the time of assembly FLOAT LEVEL ADJUSTMENT If the float level is too high or too Iow bend the float arm for adjusting Float level 24mm THROTTLE VALVE ASSEMBLY lnstall the jet needle in the valve and secure it with the clip retainer 24mm MAIN JET ...

Page 89: ...ke sure that the throttle cable is pulled tightly NOTE When installing the throttle valve align the throttle vale groove with the pilot screw CARBURETOR INSTALLATION Installation is essentially in the reverse odrer of removal After Installation adjust Throttle grip free play 2 10 Idling speed 2 11 Throttle stop screw AIR SCREW ...

Page 90: ...ufficient tire pressure STEERS TO ONE SIDE FRONT SUSPENSION NOISE 1 Bent front axle 1 Bent front fork 2 Bent front fork 2 Insufficient fluid in the front fork 3 Faulty front wheel 3 Loose front fork fasteners 4 Misadjusted shock absorber SERVICE INFORMATION GENERAL INSTRUCTIONS This section covers the removal inspection and installation of the front wheel front fork and steering Before removing th...

Page 91: ...eadlight screw Remove the headlight case Disconnect the wire connector HEADLIGHT WIRING Route the wires through the headlight Connect the wires Color to color HEADLIGHT INSTALLATION Install the headlight Install the headlight case aligning the mark to the holder tighten the bolts screw bolt ...

Page 92: ... upper holder bolts Disconnect the front brake and clutch cable from the lever Remove the handlebar holders and take off the handlebar HANDLE BAR INSTALLATION Connect the front brake and clutch cable to the lever Install the handlebar on the lower holder NOTE Install the handlebar holders NOTE TORQUE 100 140 kg m Install the light switch and throttle grip Align the punch marks on the handlebar wit...

Page 93: ...nd by placing a block under the engine Disconnect the speedometer cable and front brake cable Remove the axle nut Pull out the axle remove the front wheel FRONT WHEEL AXLE SHAFT INSPECTION Place the axle on V blocks and measure the runout the actual runout is 1 2 of the total indicator reading Service limit 0 2mm under WHEEL BEARING INSPECTION Shake the bearing back and forth and spin it by hand r...

Page 94: ...DISASSEMBLY Remove the caliper by removing the two caliper mounting bolts Remove the pad guide bolts Remove the brake pads CAUTION Do not operate the brake lever after the caliper removal to avoid brake pads sticky FRONT BRAKE ASSEMBLY Reverse the procedures of disassembly to install the brake pads Tighten the brake pad guide bolts FRONT BRAKE LINING INSPECTION DRUM BRAKE Measure the brake lining ...

Page 95: ...hown in the figure above Install the brake cam and brake arm aligning the punch mark on the brake arm with the panch mark on the cam Install the brake shoes and springs FRONT WHEEL RIM INSPECTION Check the wheel rim runout by placing the wheel on the turning stand Service limit Axial 2 0mm under Radial 2 0mm under FRONT WHEEL ASSEMBLY Apply grease to the wheel bearings Install the right bearing an...

Page 96: ...ht side Tighten the axle nut TORQUE 600 800 kgf cm Connect the speedometer cable FRONT FORK FRONT FORK REMOVAL Remove the front wheel Remove the brake caliper bolts Remove the front fender Remove the fork top bridge bolts Loosen the fork bottom bridge remove the front shock absorber assembly BOLTS TOP BRIDGE BOLTS BOTTOM BRIDGE BOLTS ...

Page 97: ...ATION Install the front fork from the bottom NOTE Turn the front fork left and right by hand while installing Tighten the fork top bridge bolts TORQUE 400 550 kgf cm Tighten the fork bottom bridge bolts TORQUE 400 550 kgf cm Install the front fender Install the front wheel STEERING STEM FRONT FORK TOP REMOVAL Remove the handlebar Remove the headlight and meter assembly Remove the front fork Remove...

Page 98: ... fall Remove the steel balls cone brace steering stem and steel balls Check the top and bottom cone races and steel balls for wear or damage and replace if necessary STEERING STEM ASSEMBLY Install the steel balls cone race DRIVE OUT DRIVER DRIVE IN DRIVER HOLDER STEEL BALLS STEERING STEM STEEL BALLS TOP CONE BRACE BOTTOM CONE BRACE STEERING LOCK ...

Page 99: ...ack the op nut out 1 8 turn to let steering stem be able to rotor freely Install the front fork top bridge Install the front fork Tighten the front fork bottom bridge bolts TORQUE 400 550 kgf cm Tighten the steering stem nut TORQUE 600 800 kgf cm Tighten the front fork top bridge bolts TORQUE 400 550 kgf cm Install the handlebar meter headlight and front wheel TOP BRIDGE BOLT FRONT FORK TOP BRIDGE...

Page 100: ...er rubber 3 Damper leaking 4 Damper and spring binding POOR BRAKE PERFORMANCE 1 Improper brake adjustment 2 Brake linings oily or worn 3 Worn brake drum 4 Brake arm serrations improperly engaged SERVICE INFORMATION TORQUE VALUES Rear wheel axle nut 1000 1200 kgf cm Rear fork pivot bolt nut 800 l000 kgf cm Rear brake torque link nut 150 200 kgf cm Shock absorber nut 300 400 kgf cm Final driven spro...

Page 101: ...rake arm Disconnect the brake torque link from the brake panel Remove the axle nut and loose the chain adjusting nut Pull out the axle shaft and remove the drive chain from the drive sprocket then remove the rear wheel AXLE INSPECTION Set the axle in the V blocks and measure the runout The actual runout is 1 2 of the total indicator reading service limit 0 2mm under ADJUSTING NUT ...

Page 102: ...in a turning stand Turn the wheel by hand and read the runout using a dial indicator gauge TORQUE 25 50 kgf cm Runout Axial 2 0mm under Radial 2 0mm under FINAL DRIVEN SPROCKET INSPECTION Check the condition of the final driven sprocket teeth Replace the sprocket if it is worn NOTE The drive chain and drive sprocket must be also inspected for wear DAMPER RUBBER INSPECTION Check the damper rubbers ...

Page 103: ...RIVEN SPROCKET ASSEMBLY Install the drive sprocket and new lock plates on the driven flange and tighten them with the bolts and nuts TORQUE 240 300 kg f cm Bend up the lock plate tabs against the nuts Install the driven flange on the wheel hub ...

Page 104: ...AKE SHOE INSPECTION Measure the lining thickness Service limit 2 0mm BRAKE SHOE REPLACEMENT Separate the brake shoes with the brake cam Remove the brake shoes and springs Grease the brake cam Install the new brake shoes WARNING Contaminated brake lining reduces stopping power Keep grease off the lining BRAKE CAM BRAKE SHOE BRAKE ARM ...

Page 105: ...justers Tighten the axle nut TORQUE 1000 1200 kg f cm Apply engine oil to the drive chain Install the step bar and the muffler SHOCK ABSORBER SHOCK ABSORBER REMOVAL Remove the left and right shock absorber assembly SHOCK ABSORBER DISASSEMBLY Compress the shock absorber spring with a shock absorber compressor Loosen the lock nut remove the upper holder HOLDER ADJUSTING NUT ...

Page 106: ...isy or leaks SHOCK ABSORBER ASSEMBLY NOTE Install the spring with the tightly wound coils at the top TORQUE 150 250kgf cm SHOCK ABSORBER INSTALLATION Tighten the shock absorber upper and lower mounting nuts TORQUE 300 400 kgf cm Check the shock absorber operation NOTE Ÿ Adjust the right and left absorber to the same scales Ÿ The standard position is 1 HOLDER SPRING COMPRESSOR SPRING COMPRESSOR ...

Page 107: ...e drive chain cover Remove the rear fork mounting bolts REAR FORK DISASSEMBLY ASSEMBLY NOTE Drive the bushings out with a soft hammer making sure that they are not damaged Lubricate with grease after installation REAR FORK INSPECTION Inspect the pivot bushing for cracks or damage Check each part for wear or damage PIVOT BOLT BUSH REAR FORK CHAIN ADJUSTER ...

Page 108: ...ll the rear shock absorber and rear wheel Install the muffler REAR BRAKE PEDAL Remove the muffler Remove the brake linkage rod Remove the brake light switch spring Remove the brake return spring Adjust the rear brake after installation NOTE Do not forget to install the brake light switch spring ADJUSTING BOLT ...

Page 109: ...W POWER KEY TURNED ON 1 Weak battery Low battery electrolyte level Charging system failure 2 Loose battery connection LOW POWER ENGINE RUNNING 1 Battery undercharged One or more dead cells Low battery electrolyte level 2 Charging system failure 3 Generator failure 4 Faulty voltage regulator 5 Faulty ignition coil 6 C D I UNIT failure INTERMITTENT POWER 1 Loose battery connection 2 Loose charging s...

Page 110: ... an emergency slow charging is preferred 3 Remove the battery from the motorcycle for charging whenever possible If battery must be charged on the motorcycle keep away from flames or sparks 4 The parts of charging system can be tested on the motorcycle 5 Refer to section 8 for generator removal and installation SPECIFICATIONS Battery Capacity Electrolyte specific gravity Charging current 12 8AH 1 ...

Page 111: ...charged 20 68 F NOTE The battery must be recharged if the specific gravity is below 1 23 The specific gravity varies with the temperature as shown in the accompanying table Replace the battery if sulfating is evident The battery must be replaced if there are pastes on the bottom of each cell WARNING The battery electrolyte contains sulfuric acid Protect your skin eyes and clothing Note the followi...

Page 112: ...nnect the cables first then turn on the power Discontinue charging if the electrolyte temperature exceeds 45 113 CAUTION Quick charging only be done in an emergency slow charging is preferred After installed the battery coat the terminals with clean grease to keep from oxidation CAUTION Route the breather tube as shown on the battery caution label CHARGING SYSTEM PERFORMANCE TEST Warm up the engin...

Page 113: ... ground Pink yellow blue white green white should not conduct electricity with ground RECTIFIER Disconnect the rectifier connector and check its performance WARNING Do not use high voltage power especially the ohmmeter or the rectifier will be burnt out RED GREEN YELLOW PINK BLACK RED GREEN YELLOW PINK BLACK Rectifier is normal if there is continuity only in the direction shown Replace the rectifi...

Page 114: ...circuit 2 High tension cord broken 3 Faulty ignition coil 4 Faulty A C generator 5 Faulty C D I unit ENGINE RUNS BUT ROUGHLY 1 Primary circuit C D I unit failure Faulty A C generator Faulty ignition coil Loose wires Poorly contacted switch terminals 2 Secondary circuit Faulty spark plug Faulty high tension cord Faulty ignition coil 3 Ignition timing Faulty A C generator Faulty C D I unit C D I Bla...

Page 115: ... sure that the battery is fully charged before diagnosing troubles in the ignition system Also refer to the following pages Spark plug 2 5 Ignition timing adjustment 2 8 SPECIFICATIONS Spark plug NGK DR7EA Spark plug gap 0 6 0 7mm 0 024 0 028in Ignition timing Initial 15 2 1500rpm Full advance 29 5 2 4000rpm ...

Page 116: ... 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 Check the primary circuit it is normal if there is conductivity when connecting a ohmmeter PRIMARY COIL 0 31 0 03KΩ SECONDARY COIL 4 0 0 4KΩ IGNITION COIL ...

Page 117: ...4 TROUBLE SHOOTING NO LIGHTS COME ON WHEN IGNITION SWITCH IS TURNED ON 1 Battery low 2 Wiring loose or blown 3 Fuse blown 4 Open or shorted wiring 5 Faulty combination switch 6 Bulb at fault or burned out ALL LIGHTS COME ON BUT DIMLY WHEN IGNITION SWITCH IS TURNED ON 1 Battery low 2 Wiring or switch has excessive resistance HEADLIGHT BEAMS DO NOT SHIFT WHEN HIGH LOW SWITCH IS OPERATED 1 Faulty dim...

Page 118: ...nd must be aligned when reconnecting A conductivity check can usually be made without removing the part from the motorcycle by simply disconnecting the wires and connecting a galvanometer or voltmeter to the terminals or connections SPECIFICATIONS Headlight 12V 35 35W Winker light 12V 10W Tail Stop light 12V 5W 21W Speedometer light 12V 3 4W x 2 Neutral pilot 12V 3 4W Winker indicator 12V 3 4W Hig...

Page 119: ...CH SKY BLUE SB GRAY Gr ORANGE O GREEN G LIGHT GREEN LG LIGHT SWITCH BLACK B BROWN Br BROWN WHITE Br W START SWTICH HAZARD SWITCH YELLOW RED Y R BLACK B GRAY Gr ORANGE O SKY BLUE SB WIRE COLOR SWITCH POSITION WIRE COLOR SWITCH POSITION WIRE COLOR WIRE COLOR SWITCH POSITION SWITCH POSITION WIRE COLOR SWITCH POSITION WIRE COLOR SWITCH POSITION WIRE COLOR SWITCH POSITION ...

Page 120: ...res The switch is normal if there is conductivity with the front brake applied REAR BRAKELIGHT SWITCH The switch is normal if there is conductivity with the rear brake applied HORN Connect the horn to a 12V battery for testing its performance Adjust tile horn if the noise is not loud enough ADJUSTING SCREW ATTACHING NUT BATTERY STOP SWITCH ...

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SANYANG INDUSTRY CO. XS125-K, Service Manual

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