KYMCO KXR 250 Service Manual Download Page 99

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. CYLINDER/PISTON

8-0

Mongoose/KXR 250

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CYLINDER /PISTON

__________________________________________________________________________________

SERVICE INFORMATION------------------------------------------------ 8- 2

TROUBLESHOOTING----------------------------------------------------- 8- 2

CYLINDER/PISTON ------------------------------------------------------- 8- 4

Summary of Contents for KXR 250

Page 1: ...ons start with an assembly or system illustration and troubleshooting for the section The subsequent pages give detailed procedures for the section KWANG YANG MOTOR CO LTD OVERSEAS SALES DEPARTMENT OV...

Page 2: ..._______________ __________________________________________________________________________________ __________________________________________________________________________________ GENERAL INFORMATIO...

Page 3: ...1 GENERAL INFORMATION 1 1 Mongoose KXR 250 SERIAL NUMBER Location of Engine Serial Number Location of Frame Serial Number...

Page 4: ...C Valve clearance Intake 0 1 cold mm Exhaust 0 1 Idle speed rpm 1500rpm Lubrication type Forced pressure Wet sump Oil pump type Inner outer rotor type Oil filter type Full flow filtration Oil capacity...

Page 5: ...tightening bolts or nuts begin with larger diameter to smaller ones at several times and tighten to the specified torque diagonally Use genuine parts and lubricants When servicing the motorcycle be su...

Page 6: ...the mutual working safety Disconnect the battery negative terminal before operation When using a spanner or other tools make sure not to damage the motorcycle surface After operation check all connec...

Page 7: ...specified capacity After operation terminal caps shall be installed securely When taking out the connector the lock on the connector shall be released before operation Hold the connector body when co...

Page 8: ...maged terminal cover or loose negative terminal Check the double connector cover for proper coverage and installation Insert the terminal completely Check the terminal cover for proper coverage Do not...

Page 9: ...o make sure that it is not interfering with any moving or sliding parts When fixing the wire harnesses do not make it contact the parts which will generate high heat Route wire harnesses to avoid shar...

Page 10: ...contact a sharp edge or corner When rubber protecting cover is used to protect the wire harnesses it shall be installed securely Do not break the sheath of wire If a wire or harness is with a broken...

Page 11: ...fere with adjacent or surrounding parts in all steering positions When a testing device is used make sure to understand the operating methods thoroughly and operate according to the operating instruct...

Page 12: ...esent the servicing methods and cautions included in this service manual Apply engine oil to the specified points Use designated engine oil for lubrication Apply grease for lubrication Transmission Ge...

Page 13: ...ks Stud bolt Oil filter screen cap Seat ball stopper bolt L cover Cam shaft holder Tappet ADJ nut Pivot tensioner bolt Lifter tensioner bolt Lifter tensioner cap Mission case bolt Mission fill bolt Dr...

Page 14: ...earenginebracketlowerbolt Enginehangerbracketbolt Exhaust muffler lock bolt frame Exhaust muffler lock nut engine Rod end nut 1 8 8 8 2 2 2 2 1 1 1 2 2 1 1 1 2 2 4 14 10 12 12 14 16 10 10 10 10 14 10...

Page 15: ...rroundings and piston ring grooves Piston pin surroundings Cylinder inside wall Connecting rod piston pin hole Connecting rod big end Crankshaft right side oil seal Crankshaft one way clutch movable p...

Page 16: ...the frame Use general purpose grease for parts not listed Apply clean engine oil or grease to cables and movable parts not specified This will avoid abnormal noise and rise the durability of the ATV S...

Page 17: ...1 GENERAL INFORMATION 1 15 Mongoose KXR 250 Sprocket hub Rear Axle Hub Collar Oil Seal Bearing Driven Sprocket Rear Swing Arm Axle...

Page 18: ...Wire Pilot Lamp Wire Handlebar Switch Wire Ignition Switch Wire Rear Brake Fluid Hose Harness Wire Motor Fan Cord Thermostatic Switch Wire Left Front Brake Fluid Hose Right Front Brake Fluid Hose Ther...

Page 19: ...250 Air Vent Tube Coolant Reservoir Breather Hose Outlet Water Hose Temperature Sensor Wire Inlet Water Hose Water Hose Carburetor Drain Tube Start Motor Cable Radiator Overflow Tube A C G Cord REG RE...

Page 20: ...RMATION 1 18 Mongoose KXR 250 Motor Fan Cord Handlebar Switch Cord Rear Brake Fluid Hose Harness Wire Blow By Hose Rear Brake Fluid Hose Start Motor Cable Battery Cable Crankcase Breather Hose Rear Br...

Page 21: ...1 GENERAL INFORMATION 1 19 Mongoose KXR 250 WIRING DIAGRAM OFF ROAD...

Page 22: ...1 GENERAL INFORMATION 1 20 Mongoose KXR 250 WIRING DIAGRAM ON ROAD...

Page 23: ...der piston and piston rings Leaking cylinder head gasket Air leaking through intake pipe Leaking intake manifold Incorrect ignition timing Incorrectly adjusted air screw Flooded carburetor Clogged air...

Page 24: ...build up in combustion chamber Poor quality fuel Clutch slipping Mixture too lean Ignition timing too early Start engine and accelerate lightly for observation Inspection Adjustment Symptom Probable...

Page 25: ...lug Faulty ignition unit Faulty A C generator Faulty ignition coil Broken or shorted spark plug wire Faulty ignition switch Remove spark plug and install it into spark plug cap to test spark by connec...

Page 26: ...lean and unclog Cam timing gear aligning marks not aligned Faulty spring Inspection Adjustment Symptom Probable Cause Check ignition timing Check carburetor jets for clogging Check fuel pump for fuel...

Page 27: ...gulator rectifier coupler red wire and battery wire to engine ground and test voltage Inspection Adjustment Inspection Adjustment Symptom Symptom Probable Cause Probable Cause Normal voltage Battery h...

Page 28: ...control unit Faulty ignition coil Replace with a new spark plug and inspect again Check ignition unit coupler for looseness Inspection Adjustment Symptom Probable Cause Normal Abnormal Normal Abnormal...

Page 29: ...__________________________________________________________________ __________________________________________________________________________________ __________________________________________________...

Page 30: ...2 FRAME COVERS EXHAUST MUFFLER 2 1 Mongoose KXR 250...

Page 31: ...r joint claws may be damaged Make sure to route cables and harnesses according to the Cable Harness Routing TORQUE VALUES Exhaust muffler lock bolt 3 2 3 8kgf m Exhaust muffler lock nut 1 8 2 2kgf m T...

Page 32: ...he screw and two bolts at the right frame cover then remove right frame cover REAR FENDER REMOVAL Remove seat See page 2 3 Remove right and left frame cover See page 2 3 Remove battery See page 16 4 R...

Page 33: ...ews attaching the frame body and three screws attaching the outlet hose then remove the rear fender HANDLEBAR COVER REMOVAL Remove the two screws at the handlebar cover Disconnect the indicator lamp c...

Page 34: ...ve the seat See page 2 3 right and left side frame cover See page 2 3 and center frame cover See page 2 5 Remove the two bolts at the front fender left side Remove the two screws attaching the inlet h...

Page 35: ...tch couplers then remove the front fender RIGHT AND LEFT FLOOR BOARD REMOVAL Remove the four screws at the floor board then remove the floor board FRONT CARRIER REMOVAL Remove the four bolts at the fr...

Page 36: ...the exhaust gas leaks the gasket should be replaced Install by reversing the removal sequence Torque Exhaust muffler lock bolt 3 2 3 8kgf m Exhaust muffler lock nut 1 8 2 2kgf m Remove the nut and bo...

Page 37: ...ECTION ADJUSTMENT __________________________________________________________________________________ SERVICE INFORMATION 3 1 MAINTENANCE SCHEDULE 3 2 FUEL LINE THROTTLE OPERATION AIR CLEANER 3 3 AIR F...

Page 38: ...d do not smoke or allow flames or sparks near the working area or fuel storage area SPECIFICATIONS ENGINE Throttle grip free play 1 4mm Spark plug gap 0 6 0 7mm Spark plug Standard DPR7EA 9 Valve clea...

Page 39: ...r dusty areas Carburetor Check idle speed starter operation Adjust if necessary Fuel line Check fuel hose for cracks or damage Replace if necessary Engine oil Replace Warm engine before draining Coola...

Page 40: ...de the rubber sleeve back to expose the throttle cable adjuster Loosen the lock nut then turn the adjuster to obtain the correct free play 1 4 mm or 0 04 0 16 in Tighten the lock nut and reinstall the...

Page 41: ...screw and remove the air cleaner assembly from the air cleaner holder Remove the air cleaner and air cleaner screen from the air cleaner body Remove the air cleaner net from the air cleaner Reassemble...

Page 42: ...d when riding in unusually dusty or rainy areas AIR CLEANER HOUSING DRAIN Remove the drain tube by removing the clip Drain the deposits Reinstall the drain tube securing it with the clip Use parts cle...

Page 43: ...irt with compressed air If the element is damaged replace it Reassemble by reversing the disassembly sequence SPARK PLUG Remove ignition coil cap and spark plug Check the spark plug for wear and fouli...

Page 44: ...and adjust by turning the adjusting nut Tappet adjuster E012 CARBURETOR IDLE SPEED Warm up the engine before this operation Start the engine and connect a tachometer Turn the throttle stop screw to o...

Page 45: ...plug Insert a compression gauge Open the throttle valve fully and push the starter button to test the compression Compression 15 2kg cm2 If the compression is low check for the following Leaky valves...

Page 46: ...level place Warm up the engine for several minutes and stop it Place a container under the engine Remove the oil fill cap and drain plug to drain the oil Reinstall the drain plug and tighten the drai...

Page 47: ...all the oil fill cap Oil Capacity At disassembly 1 6L At change 1 4L TRANSMISSION OIL REPLACEMENT Place the machine on a level place Place a container under the engine Remove the oil filler bolt and d...

Page 48: ...lt if out of specification BRAKE PADS INSPECTION A wear indicator is provided on each brake The indicators allows checking of brake pads wear Check the position of the indicator If the indicator reach...

Page 49: ...a level place Check the steering column bushings and bearings Move the handlebar up and down and or back and forth Replace the steering column bushings and or bearings if excessive play Check the tie...

Page 50: ...s Fix the handlebar straight ahead Measure the width A between the marks Rotate the front tires 180 degrees until the marks come exactly opposite Measure the width B between the marks Calculate the to...

Page 51: ...ont 6 0 8 0kgf m Rear 9 0 11 0kgf m Front Axle Nut Rear Axle Nut Be sure that both tie rod are turned the same amount If not the machine will drift tight or left even though the handlebar is positione...

Page 52: ...Replace if damage or bends Always balance the wheel when a tire or wheel has been changed or replaced Never attempt even small repairs to the wheel Ride conservatively after installing a tire to allo...

Page 53: ...Place the machine on a level place Check drive chain slack Adjust if out of specification Drive chain slack A 30 40mm Adjust drive chain slack Loosen the caliper holder bolt and two axle hub holding...

Page 54: ...chain push the ATV forward To loosen the chain pull the ATV backward Retighten the two axle hub holder bolt and caliper holder bolt to the specification Torque Axle hub holding bolt 3 5 4 5kgf m cali...

Page 55: ...phillips screwdriver and pass the standard phillips screwdriver through the shift arm into the index hole at the transmission case cover Turn the rod clockwise or counterclockwise until the drive sele...

Page 56: ...he pivoting parts of each lever REAR SUSPENSION LUBRICATION Inject grease into the nipples using a grease gun until slight over flow is observed from the thrust covers Nipple Damaged cable sheath may...

Page 57: ...emove the radiator cap Remove the drain bolt to drain the coolant Drain the coolant in the reserve tank Reinstall the drain bolt Coolant capacity 1400cc Radiator capacity 1100cc Reserve tank capacity...

Page 58: ..._____________________________________________________________________ __________________________________________________________________________________ _______________________________________________...

Page 59: ...4 LUBRICATION SYSTEM 4 1 Mongoose KXR 250 LUBRICATION SYSTEM Oil Pump Oil Filter Screen Crankshaft Rocker Arm Shaft...

Page 60: ...t be replaced as a set when it reaches its service limit After the oil pump is installed check each part for oil leaks SPECIFICATIONS Item Standard mm Service Limit mm Inner rotor to outer rotor clear...

Page 61: ...UMP REMOVAL Remove the right crankcase cover and the A C generator flywheel Refer to the A C GENERATOR FLYWHEEL section in the chapter 16 Remove the starter clutch gear Refer to the STARTER CLUTCH sec...

Page 62: ...Remove the two oil pump bolts for remove the oil pump OIL PUMP DISASSEMBLY Remove the screw and disassemble the oil pump INSPECTION Measure the rotor end to pump body clearance Service Limit 0 12mm Oi...

Page 63: ...rotor inner rotor and pump shaft into the pump body Install the dowel pin Install the pump cover by aligning the hole in the cover with the dowel pin Tighten the screw to secure the pump cover INSTAL...

Page 64: ...4 LUBRICATION SYSTEM 4 6 Mongoose KXR 250 Pump Shaft Make sure that the pump shaft rotates freely without binding Install oil pump driven sprocket and drive chain circlip and oil separator cover...

Page 65: ..._____________________________________________ __________________________________________________________________________________ _______________________________________________________________________...

Page 66: ...5 FUEL SYSTEM 5 1 Mongoose KXR 250...

Page 67: ...cleaning the carburetor air and fuel jets the O rings and diaphragm must be removed first to avoid damage Then clean with compressed air When the motorcycle is not used for over one month drain the re...

Page 68: ...jets Improper throttle operation Float level too low Intake air leak Engine idles roughly stalls or runs poorly Clogged fuel tank cap breather hole Excessively used choke Kinked or restricted fuel li...

Page 69: ...fuel tank then remove the fuel tank INSTALLATION Reverse the FUEL TANK REMOVAL procedures FUEL VALVE REMOVAL Remove the screw and then remove control switch Disconnect all fuel tubes and remove the tw...

Page 70: ...h new ones if they are damaged or deteriorated Replace the O rings with new ones if they are damaged or deteriorated ASSEMBLY Reverse the DISASSEMBLY procedures Install rubber gasket control shaft was...

Page 71: ...5 FUEL SYSTEM 5 6 Mongoose KXR 250 INSTALLATION Reverse the FUEL VALVE REMOVEAL procedures Connect all fuel tube Reserve Fuel Tube Main Fuel Tube Outlet Fuel Tube...

Page 72: ...the fuel tank Refer to FUEL TANK section in the chapter 5 Remove the carburetor cap Pull out the throttle valve Compress the spring to disconnect the throttle cable by hand Remove the spring from the...

Page 73: ...r cap Refer to FUEL TANK and THROTTLE VALVEDISASSEMBLY section in the chapter 5 Loosen the drain screw to drain the gasoline from the float chamber Loosen the screw on the lock plate for disconnect th...

Page 74: ...w Remove the two carburetor lock nuts attaching the inlet pipe Remove the carburetor DISASSEMBLY Remove the float chamber attaching three screws and remove the float chamber Remove the jet holder Pull...

Page 75: ...ttle Stop Screw Spring Washer O ring Air Screw Throttle Stop Screw Spring Slow Jet Main Jet Needle Jet Holder Needle Jet Be careful not to damage the jets and jet holder when removing them Before remo...

Page 76: ...ll passages of the carburetor body FLOAT FLOAT VALVE INSPECTION Inspect the float valve seat for wear or damage Inspect the float for damage or fuel level inside the float chamber FUEL RESERVOIR O RIN...

Page 77: ...e float level with the float level gauge while the float pin just contacts with float valve Float Level 14 8mm When adjusting carefully bend the float pin Check the float for proper operation Install...

Page 78: ...______ __________________________________________________________________________________ __________________________________________________________________________________ ___________________________...

Page 79: ...oor jack or other adjustable support is required to support and maneuver the engine Be careful not to damage the machine body cables and wires during engine removal Use shop towels to protect the mach...

Page 80: ...nnect the oil recycle tube at the cylinder head cover Disconnect the water hose from water pump cover Remove the bolt at the thermostat and disconnect the thermosensor wire then disconnect the thermos...

Page 81: ...emove the two bolts on the drive sprocket Remove the drive sprocket and washer Slide the rubber sleeve back to expose the starter motor wire nut Remove the starter motor wire nut for disconnect the st...

Page 82: ...ee bolts and remove the outlet hose cover Unscrew the clamp and then disconnect the outlet hose from the left crankcase cover Unscrew the clamp and then disconnect the inlet hose from the left crankca...

Page 83: ...ight foot peg attaching the right floor board holder Remove the nut at the right floor board holder and bolt attaching the reservoir protection cover then remove the right floor board holder Remove th...

Page 84: ...e the rear upper mounting bolt and nut Remove the front mounting bolts and nuts Remove the four bolts for remove the left and right engine brackets Remove the engine assembly to the left side of the m...

Page 85: ...6 ENGINE REMOVAL INSTALLATION 6 7 Mongoose KXR 250...

Page 86: ..._____________________________________________________ __________________________________________________________________________________ _______________________________________________________________...

Page 87: ...7 CYLINDER HEAD VALVES 7 1 Mongoose KXR 250...

Page 88: ...ly clean the removed parts and dry them with compressed air before inspection After removal mark and arrange the removed parts in order When assembling install them in the reverse order of removal SPE...

Page 89: ...at idle speed White smoke from exhaust muffler Compression too low Worn valve stem or valve guide Damaged valve stem seal Compression too low Incorrect valve clearance adjustment Abnormal noise Burned...

Page 90: ...ew cylinder head cover O ring and install the cylinder head cover Install and tighten the cylinder head cover bolts Torque 0 8 1 2kgf m CAMSHAFT CAMSHAFT HOLDER REMOVAL Remove the cylinder head cover...

Page 91: ...ins Remove the camshaft gear from the cam chain and remove the camshaft CAMSHAFT HOLDER DISASSEMBLY Take out the valve rocker arm shafts Remove the valve rocker arms arm shafts and stop plate Diagonal...

Page 92: ...stem Inspect the rocker arm bore cam lobe contact surface and adjuster surface for wear pitting scratches blue discoloration If any defects are found replace the rocker arm shaft with a new one then i...

Page 93: ...w one if the bearings are noisy or have excessive play Inspect camshaft lobes for pitting scratches blue discoloration Measure the cam lobe height Service Limits IN 34 15mm replace if below EX 34 05mm...

Page 94: ...amshaft onto the cylinder head Refer to the VALVE CLEARANCE section in the chapter 3 Install the camshaft dowel pins and holder Torque Cam shaft hold nut 2 3 2 7kgf m Apply engine oil to threads 2 Tur...

Page 95: ...buretor intake manifold Remove the bolt and disconnect the thermostat Remove the two cylinder head bolts Remove the cylinder head CYLINDER HEAD DISASSEMBLY Remove the valve spring cotters retainers sp...

Page 96: ...to obtain the stem to guide clearance Service limits IN 0 06mm replace if over EX 0 08mm replace if over CYLINDER HEAD INPECTION Check the spark plug hole and valve areas for cracks Check the cylinder...

Page 97: ...sure compressed force valve spring and installed length Replace if out of specification Service limits IN 10 20 11 84kg at 18 05mm EX 19 14 22 02kg at 21 5mm Measure the spring tilt Replace if out of...

Page 98: ...alve Spring Compressor E040 Tap the valve stems gently with a plastic hammer for 2 3 times to firmly seat the cotters INSTALLATION Install the dowel pins and a new cylinder head gasket Reverse the CYL...

Page 99: ..._______________________________________________________________________________ __________________________________________________________________________________ _____________________________________...

Page 100: ...8 CYLINDER PISTON 8 1 Mongoose KXR 250...

Page 101: ...rs check the crankcase breather for white smoke If white smoke is found it means that the piston rings are worn stuck or broken Compression too low or uneven compression Excessive smoke from exhaust m...

Page 102: ...0 055 0 09 Top 0 15 0 3 0 5 Piston Ring end gap Second 0 3 0 45 0 65 piston ring Oil ring 0 2 0 7 0 9 Piston O D 72 67 72 69 72 6 Piston O D measuring position 10mm from bottom of skirt Piston to cyli...

Page 103: ...emove the cylinder gasket and dowel pins Clean any gasket material from the cylinder surface Remove the piston pin clip Press the piston pin out of the piston and remove the piston Dowel Pins Gasket C...

Page 104: ...and measure the piston ring to groove clearance Service Limits Top 0 09mm replace if over 2nd 0 09mm replace if over Remove the piston rings and insert each piston ring into the cylinder bottom Measur...

Page 105: ...t 90 to the piston pin in both X and Y directions Cylinder I D Service Limit 72 8mm replace if over Measure the cylinder to piston clearance Service Limit 0 1mm repair or replace if over The true roun...

Page 106: ...ure the connecting rod to piston pin clearance Service Limit 0 06mm replace if over Inspect the exhaust side and intake side chain guides Wear Damage Replace Second Side Rail Top Side Rail Oil Ring Be...

Page 107: ...piston rings with clean engine oil Carefully lower the cylinder over the piston by compressing the piston rings Apply proper clean engine oil around cylinder wall Be careful not to damage or break th...

Page 108: ...9 DRIVE AND DRIVEN PULLEYS 9 0 Mongoose KXR 250 9 DRIVE AND DRIVEN PULLEYS SERVICE INFORMATION 9 2 TROUBLESHOOTING 9 2 LEFT CRANKCASE COVER 9 3 DRIVE PULLEY 9 4 CLUTCH DRIVEN PULLEY 9 7 9...

Page 109: ...9 DRIVE AND DRIVEN PULLEYS 9 1 Mongoose KXR 250...

Page 110: ...ng thickness 0 5 Clutch outer I D 153 0 153 2 153 5 Driven face spring free length 131 Driven face O D 39 965 39 985 39 94 Movable driven face I D 40 000 40 025 40 06 Weight roller O D 22 92 23 08 22...

Page 111: ...the starting cover Remove the dowel pins and gasket Remove the three bolts Remove the outlet hose cover Loosen the drive belt air inlet and outlet hose band screws and disconnect them from the left cr...

Page 112: ...E COVER REMOVAL procedures Install the left crankcase cover and tighten the bolts Connect the drive belt air inlet and outlet hose and tighten band screws Install the starting cover and outlet hose co...

Page 113: ...ace assembly and drive pulley collar DISASSEMBLY Remove the ramp plate Remove the six weight rollers INSPECTION Check each weight roller for wear or damage Measure each weight roller O D Service Limit...

Page 114: ...O D of the drive pulley collar sliding surface Service Limit 26 94mm replace if below INSTALLATION Install the drive pulley face assembly and collar Install the drive pulley wash and nut Torque 9 0 10...

Page 115: ...tch outer with the universal holder and remove the clutch outer nut Universal Holder E017 Remove the wash collar and clutch outer Remove the clutch driven pulley and drive belt DRIVE BELT INSPECTION C...

Page 116: ...ssor Clutch Spring Compressor E027 Set the clutch spring compressor in a vise and remove the clutch drive plate nut Loosen the clutch spring compressor and disassemble the clutch driven pulley assembl...

Page 117: ...en face Measure the clutch lining thickness Service Limit 0 5mm replace if below INSPECTION Measure the driven face spring free length Service Limit 131mm replace if below Check the driven face for we...

Page 118: ...ven face Apply grease to the outer bearing Drive a new outer bearing into the driven face with the sealed end facing up Bearing Puller E008 Seat the snap ring in its groove Apply grease to the driven...

Page 119: ...N PULLEYS 9 11 Mongoose KXR 250 CLUTCH DISASSEMBLY Remove the circlips and retainer plate to disassemble the clutch CLUTCH DRIVEN PULLEY ASSEMBLY Circlip Retainer Plate Clutch Lining Keep grease off t...

Page 120: ...ase to the guide rollers and guide roller pins and then install them into the holes of the driven face Install the seal collar Remove any excessive grease Set the driven pulley assembly driven face sp...

Page 121: ...e clutch driven pulley and driven belt onto the drive shaft Install the clutch outer collar and washer Hold the clutch outer with the flywheel holder Install and tighten the clutch outer nut Torque 5...

Page 122: ...__________________________________________________________________ __________________________________________________________________________________ __________________________________________________...

Page 123: ...10 FINAL REDUCTION TRANSMISSION SYSTEM 10 1 Mongoose KXR 250...

Page 124: ...he drive shaft use a special tool to hold the bearing inner race for this operation SPECIFICATIONS Specified Oil GEAR OIL SAE 90 Oil Capacity At change 0 3 liter At disassembly 0 4 liter TORQUE VALUES...

Page 125: ...N OIL REPLACEMENT section in the chapter 3 Remove the three and then remove the drive sprocket cover Remove the two bolts and then remove the washer and drive sprocket Remove the bolt and then disconn...

Page 126: ...the drive axle from the transmission case cover Remove the bearing circlip for remove the bearing Inspect the bearing for allow play in the transmission case cover or the bearing turns roughly If any...

Page 127: ...ring with a new one ASSEMBLY Install the needle bearing Install the oil seal and bearing Install the bearing circlip Install the drive axle and drive axle cirelip TRANSMISSION REMOVAL Remove the trans...

Page 128: ...RANSMISSION SYSTEM 10 6 Mongoose KXR 250 Remove the stopper plug Remove spring washer and shift cam stopper Remove the transmission guide bar Remove shift cam Shift Cam Stopper Washer Spring Plug Plug...

Page 129: ...ut of specification Replace Service Limit Less than 0 03 mm Inspect the shift fork cam follower and shift fork pawl Scoring beads wear Replace Check the shift cam groove and shift cam gear Wear or dam...

Page 130: ...Inspect shift shaft Damage bends wear Replace Remove the main axle MAIN AXLE DISASSEMBLY Remove the washers collar primary driven gear bush and clutch dog Shift Shaft Gear Shift Shaft Main Axle Colla...

Page 131: ...en remove the washers reverse wheel gear and needle bearing Inspect the gear teeth Blue discoloration pitting wear Replace Inspect the mated dogs Rounded edges cracks missing portions Replace Circlip...

Page 132: ...ION SYSTEM 10 10 Mongoose KXR 250 MAIN AXLE ASSEMBLY Reverse the MAIN AXLE DISASSEMBLY procedures Washer Circlip Needle Bearing Reverse Wheel Gear Main Axle Washer Primary Driven Gear Clutch Dog Colla...

Page 133: ...LE REMOVAL Remove the clutch driven pulley Refer to the chapter 9 Remove the oil seal circlip screw and plate Remove the primary drive axle Inspect the bearings for allow play in the transmission case...

Page 134: ...stall the dowel pins and a new gasket onto the right crankcase Install the transmission case cover and tighten the transmission case cover bolt Torque 2 4 3 0kgf m Fill the engine with oil and install...

Page 135: ..._____________________________________________________________________ __________________________________________________________________________________ _______________________________________________...

Page 136: ...11 CRANKCASE CRANKSHAFT BALANCE SHAFT 11 1 Mongoose KXR 250...

Page 137: ...apter 7 Cylinder piston Chapter 8 Drive and driven pulleys Chapter 9 A C generator Chapter 16 Starter clutch Chapter 18 Oil pump Chapter 4 SPECIFICATIONS Item Standard mm Service Limit mm Connecting r...

Page 138: ...OVAL Remove the timing chain from right crankcase Remove the left and right crankcase attaching bolts Separate the left and right crankcase halves Remove the gasket and dowel pins Remove the crankshaf...

Page 139: ...from the crankcase mating surfaces Inspect the balance shaft gear teeth Burrs chips roughness wear Replace CRANKSHAFT INSPECTION Inspect the crankshaft gear teeth Burrs chips roughness wear Replace Me...

Page 140: ...e Limit 0 10mm replace if over Measure the connecting rod big end side clearance C Service Limit 0 6mm replace if over Measure the crank width D Out of specification 55 15 55 2 mm Replace the cranksha...

Page 141: ...Install the balance shaft and crankshaft into the left crankcase Install the dowel pins and new gasket Install the right crankcase and tighten the crankcase attach bolts Install the timing chain Align...

Page 142: ...__________________________________________ __________________________________________________________________________________ __________________________________________________________________________...

Page 143: ...led coolant with fresh water as soon as possible After servicing the system check for leaks with a cooling system tester SPECIAL TOOL Mechanical seal driver TORQUE VALUES Water pump impeller 1 0 1 4kg...

Page 144: ...1 032 35 1 063 1 062 1 060 1 058 1 056 1 054 1 052 1 049 1 046 1 043 1 040 40 1 072 1 070 1 068 1 066 1 064 1 062 1 059 1 056 1 053 1 050 1 047 45 1 080 1 078 1 076 1 074 1 072 1 069 1 056 1 063 1 062...

Page 145: ...econds Radiator Cap Relief Pressure 0 75 1 05kg cm Install the radiator tester onto the radiator and apply specified pressure to it It must hold specified pressure for at least six seconds Check the w...

Page 146: ...nt fender 2 5 Disconnect the air vent tube from the radiator filler Remove the overflow tube clamp and disconnect the overflow tube Disconnect the fan motor wire coupler Remove the two bolts on the ra...

Page 147: ...stall the fan shroud on the radiator with the three bolts RADIATOR INSTALLATION Reverse the RADIATOR REMOVAL procedures Fill the radiator with coolant 3 20 Connect the vent tube to the radiator filler...

Page 148: ...cover and replace the mechanical seal WATER PUMP IMPELLER REMOVAL Drain the coolant 3 20 Loosen the screw and disconnect the coolant inlet hose Remove the four bolts and the water pump cover Remove th...

Page 149: ...nnect the water hose from the right crankcase cover Remove the twelve bolts attaching the right crankcase cover Remove the water pump bearing snap ring from the water pump assembly Remove the water pu...

Page 150: ...al seal out of the water pump assembly from the inside Drive in a new mechanical seal using a mechanical seal driver Inner Bearing Apply sealant to the right crankcase cover fitting surface of a new m...

Page 151: ...the right crankcase cover Tighten the twelve bolts to secure the right crankcase cover WATER PUMP IMPELLER INSTALLATION When the mechanical seal is replaced a new seal washer must be installed to the...

Page 152: ...pan of water over a burner and measure the resistance through the sensor as the water heats up Temperature 50 80 100 120 Resistance 154 52 27 16 THERMOSENSOR INSTALLATION Apply 3 BOND No 1212 sealant...

Page 153: ...the water hose from the thermostat housing Disconnect the air vent tube from the thermostat housing Remove the mounting bolt and the thermostat housing from the cylinder head Remove the two screws and...

Page 154: ...OSTAT INSTALLATION The installation sequence is the reverse of removal Fill the cooling system with the specified coolant 3 20 O ring Thermosensor Thermostat Thermometer Do not let the thermostat touc...

Page 155: ...___________________________________________________________________________ __________________________________________________________________________________ BRAKE SYSTEM ____________________________...

Page 156: ...13 BRAKE SYSTEM 13 1 Mongoose KXR 250...

Page 157: ...plash of brake fluid with a clean towel Do not wipe the machine with a towel contaminated by brake fluid Make sure to use recommended brake fluid Use of other unspecified brake fluids may cause brake...

Page 158: ...e brake caliper Compress the brake caliper holder and remove brake pads A wear indicator is provided on each brake The indicators allows checking of brake pads wear Check the position of the indicator...

Page 159: ...t a transparent hose and syringe to the brake caliper bleed valve and then loosen the bleed valve nut Fill the brake reservoir with brake fluid and use the syringe to draw brake fluid into it until th...

Page 160: ...m 13 4 Remove fluid tube bolt and then disconnect the fluid tube Disconnect the stop light switch wires Remove the two master cylinder holder bolts and remove the master cylinder Do not splash brake f...

Page 161: ...and spring from the brake master cylinder Clean the inside of the master cylinder and brake reservoir with brake fluid INSPECTION Check the cylinder inside wall and spring for scratch corrosion or ot...

Page 162: ...the lower bolt Torque 0 8 1 2kgf m Install the brake fluid tube with the attaching bolt and two sealing washers then tighten the bolt Torque 1 8 2 5kgf m Connect the front stop switch wire connector F...

Page 163: ...liper DISASSEMBLY Remove the brake pads 13 3 Remove the brake pad spring plate Remove the piston from the brake caliper If necessary use compressed air to squeeze out the piston through the brake flui...

Page 164: ...d replace the caliper ASSEMBLY Clean all removed parts Apply silicon grease to the piston and oil seals Lubricate the brake caliper cylinder inside wall with brake fluid Install the oil seal and dust...

Page 165: ...fluid tube bolt Torque 1 8 2 5kgf m Fill the brake reservoir with the specified brake fluid and bleed air from the brake system 13 4 Make sure that the boss on the caliper correctly engages with the...

Page 166: ...he level ground Remove the two screws attaching the brake fluid reservoir cap brake lever and brake pedal Use shop towels to cover plastic parts and coated surfaces to avoid damage caused by splash of...

Page 167: ...EEDING Connect a transparent hose to the bleed valve and fully apply the brake lever pedal after continuously pull it several times Then loosen the bleed valve nut to bleed air from the brake system R...

Page 168: ...R ON THE REAR BRAKE PEDAL DISASSEMBLY Remove the brake reservoir cover Drain the brake fluid from the hydraulic brake system 13 12 Loosen the upper and lower nuts Hold the lower nut to turn clockwise...

Page 169: ...ove the circlip and then pull out the push rod washer piston and spring INSPECTION Check the cylinder inside wall and spring for scratch corrosion or other abnormal condition If any abnormal condition...

Page 170: ...DISASSEMBLY procedures Connect the brake fluid tube to the brake caliper and tighten the fluid tube bolt Torque 1 8 2 5kgf m Fill the brake reservoir with recommended brake fluid to the upper level B...

Page 171: ...d piston seals To prevent brake fluid from splashing on the parts nearby cover the parts with cloth Slightly loosen the caliper housing bolts before removing the caliper mounting bolts to facilitate l...

Page 172: ...ess Service Limit 3 0mm Measure the brake disk run out Service Limit 0 3mm ASSEMBLY Reassemble the caliper in the reverse order of disassembly procedures and observe the following points Brake fluid s...

Page 173: ...olts Torque 1 8 2 5kgf m INSTALLATION Install the rear caliper and tighten the two mounting bolts With the tube ends contacted to the caliper and install the washers and tighten the fluid tube bolts T...

Page 174: ..._________________________________ __________________________________________________________________________________ __________________________________________________________________________________...

Page 175: ...14 FRONT WHEEL FRONT SUSPENSION STEERING SYSTEM 14 1 Mongoose KXR 250...

Page 176: ...wheel nut 4 0 5 0kgf m Front wheel hub nut 6 0 8 0kgf m Steering knuckle nut 3 0 4 0kgf m Front shock absorber upper mount bolt 3 5 4 5kgf m Front shock absorber lower mount bolt 3 5 4 5kgf m SPECIAL...

Page 177: ...ng a suitable stand under the frame Measure the wheel run out Replace wheel or check bearing play if out of specification Rim run out limits Vertical 2 0mm Lateral 2 0mm INSTALLATION When reinstalling...

Page 178: ...b and then remove front wheel hub DISASSEMBLY Remove the outside collars Inspect the dust seals for wear or damage If any defects are found replace the dust seal with a new one Remove the dust seals b...

Page 179: ...e bearings Remove the bearings using a general bearing puller Remove the distance collar from the front wheel hub ASSEMBLY Install the left new bearing and dust seal into the front wheel hub Oil seal...

Page 180: ...wheel hub nut Torque 5 0 6 0kgf m Be sure the tapered side of the distance collar face the wheel Apply the grease onto the oil seal lips bearing Do not allow the bearings to tilt while driving them in...

Page 181: ...otter pin and band ends of cotter pin Always use a new cotter pin Do not loosen the wheel hub nut after torque tightening If the wheel hub nut groove is not aligned with the cotter pin hole align groo...

Page 182: ...he upper front arm from the steering knuckle Remove the front shock absorber upper mount and lower mount bolts then remove the front shock absorber and bush Disconnect the tie rod and lower front arm...

Page 183: ...r or replace the frame Check the tightening torque of the front arms securing nuts Torque 40 5 0kgf m Check the upper front arm side play by moving it from side to side If side play noticeable replace...

Page 184: ...ts Torque 4 0 5 0kgf m Check the lower front arm side play by moving it from side to side If side play noticeable replace the inner collar and bushes as a set Check the lower front arm vertical moveme...

Page 185: ...r and lower front arms and tighten the nuts Torque 3 0 4 0kgf m Install the tie rod and washer onto the steering knuckle and tighten the nut Torque 1 8 2 4kgf m Install the all cotter pins and band en...

Page 186: ...ect the tie rod Bend damage Replace Check the tie rod end movement Tie rod end exists free play or turns roughly Replace Check the tapered surface of the tie rod end Pitting wear damage Replace Adjust...

Page 187: ...5kgf m INSTALLATION Reverse the REMOVAL AND INSPECTION procedures Install the tie rod and washer onto the steering knuckle and steering column then tighten the nuts Torque 1 8 2 4kgf m steering knuckl...

Page 188: ...ection in the CHAPTER 2 Remove the right and left master cylinder and remove bands then disconnect the rear and front fluid tube from the handlebar Remove the two screws and remove the handlebar switc...

Page 189: ...ylinder on the handlebar and install the master cylinder holder with the UP mark facing up aligning the punch mark on the handlebar with the holder joint seam First tighten the upper bolt and then tig...

Page 190: ...lip with the mark in the handlebar and then install the lower holder and tighten the two screws STEERING COLUMN REMOVAL AND INSPECTION Remove handlebar 14 13 Remove the two bolts and remove the cable...

Page 191: ...sconnect the tie rods from the steering column Remove the cotter pin and nut attaching the steering column under the frame body then remove steering column and collar Inspect the collar dust seals sna...

Page 192: ...kgf m Install the cotter pin and band ends of cotter pin Assembly the steering column and tighten the two bolts Torque 1 8 2 5kgf m Install the tie rods and washer then tighten the nut Torque 3 0 4 0k...

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Page 194: ...15 REAR WHEEL AXLE SUSPENSION 15 1 Mongoose KXR 250...

Page 195: ...mm Service Limit mm Radial 2 0 Axial 2 0 TORQUE VALUES Rear wheel nut 4 0 5 0kgf m Rear shock absorber upper mount bolt 3 5 4 5kgf m Rear shock absorber lower mount bolt 3 5 4 5kgf m Rear fork axle 6...

Page 196: ...ttaching the rear wheel hub of the both rear wheels then remove the both rear wheels Remove the cotter pin and then remove nut Remove the rear wheel hub Inspect the rear wheel hub Cracks damage Replac...

Page 197: ...R 250 Measure the wheel runout Service Limit Vertical 2 0 mm Lateral 2 0mm Out of specification Replace wheel Remove the two rear axle nuts outer and inner washer and collar Remove the rear brake disk...

Page 198: ...the DRIVE CHAIN SLACK ADJUSTMENT section in the chapter 3 and remove the two bolts at the drive sprocket refer to the chapter 6 then disconnect the drive chain from the driven sprocket Remove the rear...

Page 199: ...n sprocket clip at the rear axle and then remove the driven sprocket Remove the four nuts attaching the driven sprocket holder at the driven sprocket and then remove driven sprocket Inspect the drive...

Page 200: ...ads of the rear axle Wear damage Replace Measure the rear axle run out Service limit less than 1 5mm Out of specification Replace REAR AXLE ASSEMBLY Reverse the REAR AXLE DISASSEMBLY procedures Remove...

Page 201: ...L AXLE SUSPENSION 15 8 Mongoose KXR 250 Remove the circlip at the caliper holder and then remove the caliper holder and collar Remove the rear axle hub from right side Circlip Collar Caliper Holder Re...

Page 202: ...of the rear axle hub Remove the dust seal by a flat head screw driver Remove the bearing by a general bearing puller REAR AXLE HUB ASSEMBLY Install the new bearing and dust seal by reversing the previ...

Page 203: ...ighten the nut Torque 9 0 11 0kgf m Install cotter pin new Apply grease onto the dust seal lips and bearings At this time the rear axle hub should not be tightened completely Final tightening is done...

Page 204: ...Tighten the two rear axle nuts inner and outer Nut wrench F010 Torque 11 0 13 0kgf m Adjust drive chain slack Refer to the DRIVE CHAIN SLACK ADJUSTMENT section in the CHAPTER 3 Drive chain slack 30 4...

Page 205: ...t the air cleaner case Refer to the CARBURETOR REMOVAL section in chapter 5 Elevate the air cleaner case and remove the upper mount bolt at the rear shock absorber Remove the four bolts at the lower g...

Page 206: ...ssembly Inspect the spring Fatigue Replace the shock absorber assembly Move the spring up and down Inspect the bush Wear damage Replace REAR SWING ARM DISASSEMBLY Remove the bolt attaching the lower r...

Page 207: ...EMBLY Reverse the REAR SWING ARM DISASSEMBLY procedures Install the upper rear swing arm and tighten the bolt Torque 3 5 4 5kgf m Check the tightening torque of the pivot shaft rear fork securing nut...

Page 208: ...t is tight binding or rough check the inner collar bearing bushing and thrust cover or adjust the shim Remove the band and then disconnect the rear brake fluid tubes from the rear fork Remove the nut...

Page 209: ...damage Replace Roll the axle on a flat surface to inspect the pivot shaft Bends Replace Inspect the thrust covers collar and bushes Wear damage Replace Inspect the drive chain stiffness Stiff Clean a...

Page 210: ...e rear fork and tightening the nut and pivot shaft Torque 6 0 8 0kgf m Install the rear swing arm and tightening the bolts Torque 3 5 4 5kgf m Install the shock absorber and tightening the bolts Torqu...

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Page 212: ...16 BATTERY CHARGING SYSTEM A C GENERATOR 16 1 Mongoose KXR 250 CHARGING CIRCUIT Fuse Battery Regulator Rectifier A C Generator Ignition Switch...

Page 213: ...ew battery will prolong its service life Inspect the charging system according to the sequence specified in the Troubleshooting Do not disconnect and soon reconnect the power of any electrical equipme...

Page 214: ...connection Disconnected battery cable Loose charging system connection Fuse burned out Loose connection or short circuit in Faulty ignition switch lighting system Low power Charging system failure Wea...

Page 215: ...is the reverse of removal BATTERY VOLTAGE OPEN CIRCUIT VOLTAGE INSPECTION Remove the seat Disconnect the battery cables Measure the voltage between the battery terminals Fully charged 13 1V Undercharg...

Page 216: ...2A Quick 3 0A Charging time Standard 5 10 hours Quick 30 minutes After charging Open circuit voltage 12 8V min Keep flames and sparks away from a charging battery Turn power ON OFF at the charger not...

Page 217: ...when the battery is fully charged Warm up the engine for inspection Connect the electric tester across the battery terminals Disconnect the red wire from the fuse terminal and connect an ammeter betw...

Page 218: ...Continuity Probe Probe I Yellow Green II Red White Yellow Reverse Direction No Continuity Probe Probe I Green Yellow II Yellow Red White VOLTAGE REGULATION TEST Connect a voltmeter across the battery...

Page 219: ...OVAL section in the chapter 12 Remove the pulser coil screws and then remove the A C generator wire set plate Remove the A C generator bolts and then remove A C generator and pulser coil from right cr...

Page 220: ...gf m Install the oil through guide and spring Install the A C generator onto the right crankcase cover and tighten the bolts Torque 0 8 1 0kgf m Install the right crankcase cover Special Flywheel Pull...

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Page 222: ...17 IGNITION SYSTEM 17 1 Mongoose KXR 250 IGNITION CIRCUIT Ignition Switch Ignition Unit Change Gear Control A C Generator Pulser Coil Spark Plug Ignition Coil...

Page 223: ...operation Use of spark plug with improper heat range is the main cause of poor engine performance The inspections in this section are focused on maximum voltage The inspection of ignition coil resist...

Page 224: ...gnition unit ground wire Faulty ignition coil Dead battery or faulty regulator rectifier Faulty pulser coil Faulty ignition coil connector Normal high voltage but no spark at plug Faulty pulser coil F...

Page 225: ...on Unit Change Gear Control Due to the semiconductor in circuit it is necessary to use a specified tester for accurate testing Use of an improper tester in an improper range may give false readings Us...

Page 226: ...with a new one CHANGE REAR CONTROL INSPECTION Testing Range at 20 C Note The readings in this table are taken with a YF 3501 Tester Probe Probe Green Yellow Brown Light Green Red Green Pink Green Yell...

Page 227: ...park plug cap and measure the secondary coil resistance between the spark plug wire and the primary coil terminal Resistance with plug cap 19 8K 20 C without plug cap 14 45K 20 C Measure the spark plu...

Page 228: ...Remove the front fender Refer to the chapter 2 Disconnect the pulser coil wire coupler and measure the resistance between the blue yellow and green white wire terminals Resistance 105 110 20 C Refer...

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Page 230: ...18 STARTING SYSTEM 18 1 Mongoose KXR 250 STARTING CIRCUIT Fuse Battery Starter Relay Starter Button Starter Motor Stop Switches Ignition S it h...

Page 231: ...burned out Weak battery Weak battery Loose wire or connection Faulty ignition switch Foreign matter stuck in starter motor Faulty starter clutch or gear Faulty front or rear stop switch Faulty starte...

Page 232: ...tion and replace if necessary Clean the commutator if there is metal powder between the segments Check for continuity between pairs of the commutator segments and there should be continuity Also make...

Page 233: ...continuity between the wire terminal and each brush Replace if necessary Measure the length of the brushes Service Limit 8 5mm replace if below Check for continuity between the brushes If there is con...

Page 234: ...ALLATION Connect the starter motor cable connector and properly install the waterproof rubber jacket Check the O ring for wear or damage and replace if necessary Apply grease to the O ring and install...

Page 235: ...round circuit Check for continuity between the starter relay yellow red and green red wire terminals STARTER RELAY VOLTAGE INSPECTION Connect a 12V battery across the starter relay yellow red and gree...

Page 236: ...hapter 12 Remove the flywheel Refer to the A C GENERATOR FLYWHEEL REMOVAL section in the chapter 16 Inspect the starter one way clutch for wear or damage Remove the starter driven gear Inspect the sta...

Page 237: ...r or damage INSTALLATION Reverse the REMOVAL procedures Install the starter idle gear and shaft Install the starter driven gear Install flywheel and right crankcase cover Refer to the A C GENERATOR FL...

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Page 239: ...to remove the bulb and replace with a new one Install the bulb aligning the bulb socket groove with the bulb tab and set the lock clip Install the rubber boot Install the front fender in the reverse o...

Page 240: ...move the handlebar cover See page 2 4 Remove the bulb socket by pulling it out Remove the bulb Install the bulb in the reverse order of removal FRONT TURN SIGNAL LIGHT ON ROAD ONLY Remove the turn sig...

Page 241: ...aligning the turn signal lens groove with the turn signal case tab REAR TURN SIGNAL LIGHT ON ROAD ONLY Remove the screw and remove the turn signal light lens Pull the bulb socket outside from the sig...

Page 242: ...o nuts and then remove the instrument Pull the bulb socket out and then remove the instrument bulb Install the instrument in the reverse order of removal HORN ON ROAD REMOVAL Disconnect the horn wire...

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KYMCO KXR 250, Service Manual

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