KYMCO Mongoose/KXR 250 Service Manual
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KYMCO Mongoose/KXR 250 Service Manual

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PREFACE
This Service Manual describes the
technical features and servicing
procedures for the KYMCO
Mongoose/KXR 250.
Section 1 contains the precautions for
all operations stated in this manual.
Read them carefully before starting any
operation.
Section 2 is the removal/installation
procedures for the frame covers which
are subject to higher removal/installation
frequency during maintenance and
servicing operations.
Section 3 describes the inspection/
adjustment procedures, safety rules and
service information for each part,
starting from periodic maintenance.
Sections 4 through 19 give instructions
for disassembly, assembly and
inspection of engine, chassis frame and
electrical equipment.
Most sections start with an assembly or
system illustration and troubleshooting
for the section. The subsequent pages
give detailed procedures for the section.
The information and contents included
in this manual may be different from
the motorcycle in case specifications
are changed.
KWANG YANG MOTOR CO., LTD.
OVERSEAS SALES DEPARTMENT
OVERSEAS SERVICE SECTION

TABLE OF CONTENTS

BATTERY/CHARGING SYSTEM/A.C.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19

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Summary of Contents for KYMCO Mongoose/KXR 250

  • Page 1: Table Of Contents

    PREFACE TABLE OF CONTENTS This Service Manual describes the GENERAL INFORMATION technical features and servicing FRAME COVERS/EXHAUST MUFFLER procedures for the KYMCO INSPECTION/ADJUSTMENT Mongoose/KXR 250. LUBRICATION SYSTEM Section 1 contains the precautions for FUEL SYSTEM all operations stated in this manual.

  • Page 2: General Information

    . GENERAL INFORMATION Mongoose/KXR 250 __________________________________________________________________________________ GENERAL INFORMATION SERIAL NUMBER---------------------------------------------------------- 1- 1 SPECIFICATIONS ---------------------------------------------------------- 1- 2 SERVICE PRECAUTIONS ------------------------------------------------ 1- 3 TORQUE VALUES --------------------------------------------------------- 1-11 SPECIAL TOOLS ----------------------------------------------------------- 1-12 LUBRICATION POINTS -------------------------------------------------- 1-13 CABLE & HARNESS ROUTING ---------------------------------------- 1-16 WIRING DIAGRAM-------------------------------------------------------- 1-19...

  • Page 3: General Information

    . GENERAL INFORMATION Mongoose/KXR 250 SERIAL NUMBER Location of Frame Serial Number Location of Engine Serial Number...

  • Page 4: Specifications

    . GENERAL INFORMATION Mongoose/KXR 250 SPECIFICATIONS Name & Model No. LA50AA/AB Air cleaner type & No Sponge Motorcycle Name & Type Mongoose/KXR Fuel capacity 13 liters Overall length (mm) 1700 Type Overall width (mm) 1070 Float lever 14.8mm φ Overall height (mm) 1080 Venturi dia.(mm)

  • Page 5: Service Precautions

    . GENERAL INFORMATION Mongoose/KXR 250 SERVICE PRECAUTIONS Make sure to install new gaskets, O-rings, circlips, cotter pins, etc. when reassembling. When tightening bolts or nuts, begin with larger-diameter to smaller ones at several times, and tighten to the specified torque diagonally.
  • Page 6 . GENERAL INFORMATION Mongoose/KXR 250 Apply or add designated greases and lubricants to the specified lubrication points. After reassembly, check all parts for proper tightening and operation. When two persons work together, pay attention to the mutual working safety. Disconnect the battery negative (-) terminal before operation.
  • Page 7 . GENERAL INFORMATION Mongoose/KXR 250 If the fuse is burned out, find the cause Confirm and repair it. Replace it with a new one Capacity according to the 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.
  • Page 8 . GENERAL INFORMATION Mongoose/KXR 250 The connector shall be inserted completely. Snapping! If the double connector has a lock, lock it at the correct position. Check if there is any loose wire. Before connecting a terminal, check for damaged terminal cover or loose negative terminal.
  • Page 9 . GENERAL INFORMATION Mongoose/KXR 250 After clamping, check each wire to make sure it is secure. Do not squeeze wires against the weld or its clamp. After clamping, check each harness to make sure that it is not interfering with any moving or sliding parts.
  • Page 10 . GENERAL INFORMATION Mongoose/KXR 250 Route harnesses so they are neither pulled tight nor have excessive slack. Do not pull too tight! Protect wires and harnesses with electrical tape or tube if they contact a sharp edge or corner. When rubber protecting cover is used to protect the wire harnesses, it shall be installed securely.
  • Page 11 . GENERAL INFORMATION Mongoose/KXR 250 After routing, check that the wire harnesses are not twisted or kinked. Wire harnesses routed along with handlebar should not be pulled tight, have excessive slack or interfere with adjacent or surrounding parts in all steering positions.
  • Page 12 . GENERAL INFORMATION Mongoose/KXR 250 Symbols: The following symbols represent the servicing methods and cautions included in this service manual. : Apply engine oil to the specified points. (Use designated engine oil for lubrication.) Engine Oil : Apply grease for lubrication.

  • Page 13: Torque Values

    . GENERAL INFORMATION Mongoose/KXR 250 TORQUE VALUES STANDARD TORQUE VALUES Item Torque (kgf-m) Item Torque (kgf-m) 5mm bolt and nut 0.45～0.6 4mm screw 0.2～0.4 6mm bolt and nut 0.8～1.2 0.35～0.5 5mm screw 8mm bolt and nut 1.8～2.5 0.7～1.1 6mm screw, SH bolt 10mm bolt and nut 3.0～4.0...

  • Page 14: Special Tools

    . GENERAL INFORMATION Mongoose/KXR 250 FRAME Item Q‘ty Thread dia.(mm) Torque (kgf-m) Remarks Steering stem nut 6.0～8.0 Front swing arm nut 4.0～5.0 Front wheel nut 4.0～5.0 Rear wheel nut 4.0～5.0 Front wheel hub nut 6.0～8.0 Rear wheel hub nut 9.0～11.0 Front shock absorber upper mount bolt 3.5～4.5...

  • Page 15: Lubrication Points

    . GENERAL INFORMATION Mongoose/KXR 250 LUBRICATION POINTS ENGINE Lubrication Points Lubricant •Genuine KYMCO Engine Oil (SAE15W-40) Valve guide/valve stem movable part •API SG Engine Oil Cam lobes Valve rocker arm friction surface Cam chain Cylinder lock bolt and nut Piston surroundings and piston ring grooves...
  • Page 16 . GENERAL INFORMATION Mongoose/KXR 250 FRAME The following is the lubrication points for 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.
  • Page 17 . GENERAL INFORMATION Mongoose/KXR 250 Rear Swing Arm Axle Sprocket hub/Rear Axle Hub Collar/Oil Seal/Bearing Driven Sprocket 1-15...

  • Page 18: Cable & Harness Routing

    . GENERAL INFORMATION Mongoose/KXR 250 CABLE & HARNESS ROUTING Pilot Lamp Wire Headlight Wire Throttle Cable Handlebar Switch Wire Stop Switch Cord Rear Brake Fluid Hose Front Brake Fluid Hose Harness Wire Thermostatic Sensor Wire Motor Fan Cord Ignition Switch Wire...
  • Page 19 . GENERAL INFORMATION Mongoose/KXR 250 Temperature Sensor Wire Air Vent Tube Tail Light Cord REG.REC Cord Coolant Reservoir A.C.G Cord Breather Hose Start Motor Cable Water Hose Stop Switch Cord Radiator Overflow Tube Carburetor Drain Tube Outlet Water Hose Inlet Water Hose...
  • Page 20 . GENERAL INFORMATION Mongoose/KXR 250 Rear Brake Fluid Hose Crankcase Breather Hose Harness Wire Handlebar Switch Cord Blow By Hose Battery Cable Motor Fan Cord Start Motor Cable Rear Brake Fluid Hose Rear Brake Fluid Hose 1-18...

  • Page 21: Wiring Diagram

    . GENERAL INFORMATION Mongoose/KXR 250 WIRING DIAGRAM (OFF ROAD) 1-19...
  • Page 22 . GENERAL INFORMATION Mongoose/KXR 250 WIRING DIAGRAM (ON ROAD) 1-20...

  • Page 23: Troubleshooting

    . GENERAL INFORMATION Mongoose/KXR 250 TROUBLESHOOTING ENGINE WILL NOT START OR IS HARD TO START Inspection/Adjustment Probable Cause Symptom Check if fuel reaches carburetor by loosening drain screw Empty fuel tank Clogged fuel line between fuel tank and carburetor Clogged float oil passage...
  • Page 24 . GENERAL INFORMATION Mongoose/KXR 250 ENGINE LACKS POWER Inspection/Adjustment Probable Cause Symptom Start engine and accelerate lightly for observation Clogged air cleaner Restricted fuel flow Engine speed Engine speed does not Clogged fuel tank cap breather hole increase sufficiently increases...
  • Page 25 . GENERAL INFORMATION Mongoose/KXR 250 POOR PERFORMANCE (ESPECIALLY AT IDLE AND LOW SPEEDS) Inspection/Adjustment Symptom Probable Cause Check ignition timing Faulty ignition unit Incorrect timing Correct timing Faulty pulser coil Check carburetor air screw adjustment Mixture too rich (turn screw...
  • Page 26 . GENERAL INFORMATION Mongoose/KXR 250 POOR PERFORMANCE (AT HIGH SPEED) Inspection/Adjustment Symptom Probable Cause Check ignition timing Faulty ignition unit Correct timing Incorrect timing Faulty pulser coil Check valve clearance Improperly adjusted valve Correctly adjusted Incorrectly adjusted clearance Worn valve seat...
  • Page 27 . GENERAL INFORMATION Mongoose/KXR 250 POOR CHARGING (BATTERY OVER DISCHARGING OR OVERCHARGING) Undercharging Inspection/Adjustment Symptom Probable Cause Start engine and test limit voltage of battery terminals Dead battery Voltage does not Normal voltage increase Faulty battery Measure resistance between AC generator coil terminals Faulty A.C.
  • Page 28 . GENERAL INFORMATION Mongoose/KXR 250 NO SPARK AT SPARK PLUG Inspection/Adjustment Symptom Probable Cause Replace with a new spark plug and inspect again Good spark Weak or no spark Faulty spark plug Check spark plug cap and high-tension wire for looseness...

  • Page 29: Frame Covers/Exhaust Muffler

    . FRAME COVERS/EXHAUST MUFFLER Mongoose/KXR 250 __________________________________________________________________________________ FRAME COVERS/EXHAUST MUFFLER SERVICE INFORMATION------------------------------------------------ 2- 2 TROUBLESHOOTING----------------------------------------------------- 2- 2 FRAME COVERS ----------------------------------------------------------- 2- 3 EXHAUST MUFFLER REMOVAL-------------------------------------- 2- 7...

  • Page 30: Frame Covers/Exhaust Muffler

    . FRAME COVERS/EXHAUST MUFFLER Mongoose/KXR 250...

  • Page 31: Service Information

    . FRAME COVERS/EXHAUST MUFFLER Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • When removing frame covers, use special care not to pull them by force because the cover joint claws may be damaged. • Make sure to route cables and harnesses according to the Cable & Harness Routing.

  • Page 32: Frame Covers

    . FRAME COVERS/EXHAUST MUFFLER Mongoose/KXR 250 Seat Lever FRAME COVERS SEAT REMOVAL Pull the lever right and pull up the seat at the rear. Remove the seat. Bolts Frame Left Cover LEFT/RIGHT FRAME COVER REMOVAL Remove the seat. (See page 2-3) Remove the screw and two bolts at the left frame cover, then remove left frame cover.
  • Page 33 . FRAME COVERS/EXHAUST MUFFLER Mongoose/KXR 250 Bolts Remove the three bolts at the rear fender. Screws Remove the two screws attaching the right and left floor board. Screws Screws Remove the two screws attaching the frame body and three screws attaching the outlet hose, then remove the rear fender.
  • Page 34 . FRAME COVERS/EXHAUST MUFFLER Mongoose/KXR 250 Bolts CENTER FRAME COVER REMOVAL Remove the seat. (See page 2-3) Remove the fuel fill cap. Remove the four bolts at the center frame cover, then remove the center frame cover. After remove, be sure to tighten the fuel fill cap.
  • Page 35 . FRAME COVERS/EXHAUST MUFFLER Mongoose/KXR 250 Disconnect headlight and ignition switch couplers, then remove the front fender. Ignition Coupler Headlight Coupler RIGHT AND LEFT FLOOR BOARD REMOVAL Remove the four screws at the floor board, then remove the floor board.

  • Page 36: Exhaust Muffler Removal

    . FRAME COVERS/EXHAUST MUFFLER Mongoose/KXR 250 EXHAUST MUFFLER REMOVAL Remove the two exhaust pipe joint lock nuts. Remove the bolt at the exhaust muffler, disconnect the exhaust pipe from the exhaust muffler. Nuts Bolt Gasket Inspect the gasket. If the exhaust gas leaks, the gasket should be replaced.

  • Page 37: Inspection/Adjustment

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 __________________________________________________________________________________ INSPECTION/ADJUSTMENT SERVICE INFORMATION------------------------------------------------ 3- 1 MAINTENANCE SCHEDULE-------------------------------------------- 3- 2 FUEL LINE/THROTTLE OPERATION/AIR CLEANER ------------ 3- 3 AIR FILTER FOR DRIVE BELT/ SPARK PLUG --------------------- 3- 6 VALVE CLEARANCE/CARBURETOR IDLE SPEED--------------- 3- 7 IGNITION TIMING/CYLINDER COMPRESSION ------------------- 3- 8...

  • Page 38: Inspection/Adjustment

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 SERVICE INFORMATION GENERAL WARNING •Before running the engine, make sure that the working area is well-ventilated. Never run the engine in a closed area. The exhaust contains poisonous carbon monoxide gas which may cause death to people.

  • Page 39: Maintenance Schedule

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 MAINTENANCE SCHEDULE This chapter includes all information necessary to perform recommended inspections and adjustments. These preventive maintenance procedures, if followed, will ensure more reliable vehicle operation and a longer service life. The need for costly overhaul work will be greatly reduced.

  • Page 40: Fuel Line/Throttle Operation/Air Cleaner

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Fuel Filter FUEL LINE Check the fuel tubes and replace any parts, which show signs of deterioration, damage or leakage. Do not smoke or allow flames or sparks in your working area. Fuel tubes Lock nut...
  • Page 41 . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Screw Air Cleaner Assembly Unscrew the clamp and remove the air cleaner assembly from the air cleaner housing. Screw Air Cleaner Holder Remove the screw and remove the air cleaner assembly from the air cleaner holder.
  • Page 42 . INSPECTION/ADJUSTMENT Mongoose/KXR 250 CLEAN AIR FILTER ELEMENT Wash the element gently, but throughly in solvent. Use parts cleaning solvent only. Never use gasoline or low flash point solvents which may lead to a fire or explosion. Squeeze the excess solvent out of the element and let dry.

  • Page 43: Air Filter For Drive Belt/ Spark Plug

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Air Filter Cover AIR FILTER FOR DRIVE BELT To clean the air filter: Remove the two screws attaching front fender and remove air filter housing. Remove the two screws and remove air filter housing cover. Screws...

  • Page 44: Valve Clearance/Carburetor Idle Speed

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Cylinder Head Cover VALVE CLEARANCE Inspect and adjust valve clearance while the engine is cold (below 35 ). Remove the cylinder head cover. (See page 7-4) Index Mark “T” Mark Turn the flywheel clockwise so that the “T”...

  • Page 45: Ignition Timing/Cylinder Compression

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Timing Hole Cap Index Mark IGNITION TIMING The ignition unit is not adjustable. If the ignition timing is incorrect, check the ignition system. Remove the timing hole cap. Check the ignition timing with a timing light.

  • Page 46: Engine Oil

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Upper Level ENGINE OIL OIL LEVEL Place the machine on a level place. Warm up the engine for several minutes and stop it. Run the engine for 2～3 minutes and check the oil level after the engine is stopped for 2～3 minutes.

  • Page 47: Transmission Oil Replacement

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 ENGINE OIL REPLACEMENT AND OIL FILTER CLEANING Place the machine on a level place. Warm up the engine for several minutes and stop it. Place a container under the engine. Remove the oil fill cap and oil filter cap to drain the oil.

  • Page 48: Drive Belt/Brake Pads/Brake Fluid Inspection

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Drive Belt DRIVE BELT Remove the left crankcase cover. Inspect the drive belt for cracks, scaling, chipping or excessive wear. Measure the V-belt width Service limit: 22mm Replace the drive belt if out of specification. BRAKE PADS INSPECTION A wear indicator is provided on each brake.

  • Page 49: Headlight Aim/ Steering System Inspection

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Inspection Window (Rear Brake Pedal) Adjust Screw HEADLIGHT AIM Turn the ignition switch ON and start the engine. Turn on the headlight switch. Adjust the headlight aim by turning the headlight aim adjusting screw. STEERING SYSTEM INSPECTION Place the machine on a level place.

  • Page 50: Toe-In Adjustment

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Raise the front end of the machine so that there is no weight on the front wheels. Check ball joints and/or wheel bearings. Move the wheels lately back and froth. Replace the front arms and/or wheel bearings if excessive free play.

  • Page 51: Wheels/Tires

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Tie-rod End Nuts • 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 positioned straight which may lead to mishandling and accident.
  • Page 52 . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Inspect the tire surfaces. Replace if wear or damage. Tire wear limit: 3.0mm It is dangerous to ride with a worn out tire. When a tire wear is out of specification, replace the tire immediately. WHEEL INSPECTION Inspect the wheel.

  • Page 53: Drive Chain Slack Adjustment

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 DRIVE CHAIN SLACK ADJUSTMENT Before checking and/or adjusting, rotate the rear wheels several revolutions and check slack at several points to find the tightest point. Check and/or adjust the chain slack with the rear wheels in this “tightest”...
  • Page 54 . INSPECTION/ADJUSTMENT Mongoose/KXR 250 To tighten the chain, push the ATV forward. To loosen the chain, pull the ATV backward. Bolt Bolts Retighten the two axle hub holder bolt and caliper holder bolt to the specification. Torque: Axle hub holding bolt: 3.5～4.5kgf-m caliper holder bolt: 0.8～1.2kgf-m...

  • Page 55: Drive Select Lever Adjustment

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Standard/Phillips Screwdriver DRIVE SELECT LEVER ADJUSTMENT Turn the ignition switch is ON and make sure the engine stop switch in the OFF position. Loosen the lock nuts of rod. Shift the gear to neutral by moving the shift lever and/or turn the rod.

  • Page 56: Cable Inspection And Lubrication

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 CABLE INSPECTION AND LUBRICATION Damaged cable sheath may cause corrosion and interfere with the cable movement. An unsafe condition may result so replace such cable as soon as possible. Inspect the cable sheath. Replace if damage.

  • Page 57: Cooling System

    . INSPECTION/ADJUSTMENT Mongoose/KXR 250 Maximum Mark Minimum Mark COOLING SYSTEM COOLANT LEVEL INSPECTION Place the machine on the level ground. Check the coolant level in the coolant reservoir when the engine is cold as the coolant level will vary with engine temperature.

  • Page 58: Lubrication System

    . LUBRICATION SYSTEM Mongoose/KXR 250 __________________________________________________________________________________ LUBRICATION SYSTEM SERVICE INFORMATION------------------------------------------------ 4- 2 TROUBLESHOOTING----------------------------------------------------- 4- 2 ENGINE OIL/OIL FILTER ------------------------------------------------ 4- 3 OIL PUMP -------------------------------------------------------------------- 4- 3...

  • Page 59: Lubrication System

    . LUBRICATION SYSTEM Mongoose/KXR 250 LUBRICATION SYSTEM Rocker Arm Shaft Crankshaft Oil Filter Screen Oil Pump...

  • Page 60: Service Information

    . LUBRICATION SYSTEM Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • The maintenance of lubrication system can be performed with the engine installed in the frame. • Use care when removing and installing the oil pump not to allow dust and foreign matters to enter the engine and oil line.

  • Page 61: Engine Oil/Oil Filter

    . LUBRICATION SYSTEM Mongoose/KXR 250 ENGINE OIL/OIL FILTER OIL LEVEL AND OIL CHANGE Refer to the “ENGINE OIL” section in the chapter 3 to check the oil level and replacement and oil filter cleaning. OIL PUMP REMOVAL Remove the right crankcase cover and the A.C.
  • Page 62 . LUBRICATION SYSTEM Mongoose/KXR 250 Oil Pump Driven Sprocket Oil Pump Drive Chain Remove the two oil pump bolts for remove the oil pump. Oil Pump Bolts Screw OIL PUMP DISASSEMBLY Remove the screw and disassemble the oil pump. Pump Body...
  • Page 63 . LUBRICATION SYSTEM Mongoose/KXR 250 Measure the inner rotor-to-outer rotor Inner Rotor clearance. Service Limit: 0.2mm Outer Rotor Measure the pump body-to-outer rotor Outer Rotor clearance. Service Limit: 0.25mm Pump Body ASSEMBLY Pump Cover Outer Rotor Install the outer rotor, inner rotor and pump shaft into the pump body.
  • Page 64 . LUBRICATION SYSTEM 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: Fuel System

    . FUEL SYSTEM Mongoose/KXR 250 __________________________________________________________________________________ FUEL SYSTEM SERVICE INFORMATION------------------------------------------------ 5- 2 TROUBLESHOOTING----------------------------------------------------- 5- 3 FUEL TANK ----------------------------------------------------------------- 5- 4 FUEL VALVE REMOVAL ------------------------------------------------ 5- 4 THROTTLE VALVE---------------------------------------------------------- 5- 7 CARBURETOR-------------------------------------------------------------- 5- 8 AIR CLEANER -------------------------------------------------------------- 5-12...

  • Page 66: Fuel System

    . FUEL SYSTEM Mongoose/KXR 250...

  • Page 67: Service Information

    . FUEL SYSTEM Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS Gasoline is very dangerous. When working with gasoline, keep sparks and flames away from the working area. Gasoline is extremely flammable and is explosive under certain conditions. Be sure to work in a well-ventilated area.

  • Page 68: Troubleshooting

    . FUEL SYSTEM Mongoose/KXR 250 SPECIAL TOOL Float level gauge TROUBLESHOOTING Engine cranks but won’t start Engine lacks power • No fuel in tank • Clogged air cleaner • No fuel to carburetor • Faulty carburetor • Cylinder flooded with fuel •...

  • Page 69: Fuel Tank

    . FUEL SYSTEM Mongoose/KXR 250 FUEL TANK REMOVAL Warning • Keep sparks and flames away from the work area. • Wipe off any spilled gasoline. Remove the seat, right and left side frame cover (See page 2-3) and center frame cover (See page 2-5).
  • Page 70 . FUEL SYSTEM Mongoose/KXR 250 Control Shaft Washer Screws DISASSEMBLY Remove the two screws on the retaining ring and then remove retaining ring. Remove the washer and control shaft. Retaining Ring Fuel Valve Body Rubber Gasket Remove the rubber gasket from the fuel valve body.
  • Page 71 . FUEL SYSTEM Mongoose/KXR 250 Main Fuel Tube INSTALLATION Reverse the “FUEL VALVE REMOVEAL” procedures. Connect all fuel tube. Outlet Fuel Tube Reserve Fuel Tube...

  • Page 72: Throttle Valve

    . FUEL SYSTEM Mongoose/KXR 250 Carburetor Cap THROTTLE VALVE DISASSEMBLY Remove the fuel tank. (Refer to “FUEL TANK” section in the chapter 5) Remove the carburetor cap. Throttle Valve Pull out the throttle valve. Throttle Cable Compress the spring to disconnect the throttle cable by hand.

  • Page 73: Carburetor

    . FUEL SYSTEM Mongoose/KXR 250 Needle Retainer Throttle Valve Pry off the needle retainer and remove the jet needle. Check the throttle valve and jet needle for wear or damage. ASSEMBLY Reverse the “DISASSEMBLY” procedures. Jet Needle Clip Groove Install the throttle valve into the carburetor body.
  • Page 74 . FUEL SYSTEM Mongoose/KXR 250 Bolts Band Remove the two bolts at the air cleaner case. Loosen the air cleaner connecting tube band screw. Remove the two carburetor lock nuts attaching the inlet pipe. Remove the carburetor Nuts Float Chamber...
  • Page 75 . FUEL SYSTEM Mongoose/KXR 250 Slow Jet Throttle Stop Screw Remove the main jet, needle jet holder, and needle jet. Remove the slow jet. Remove the air screw and throttle stop screw. Main Jet Air Screw Spring Throttle Stop Screw CAUTIONS! •...
  • Page 76 . FUEL SYSTEM Mongoose/KXR 250 Spring Diaphragm Remove the spring, diaphragm and O-rings. Inspect the diaphragm and spring for wear or damage. Cover O-ring CARBURETOR CLEANING Blow compressed air through all passages of the carburetor body. Float Valve FLOAT/FLOAT VALVE INSPECTION Inspect the float valve seat for wear or damage.

  • Page 77: Air Cleaner

    . FUEL SYSTEM Mongoose/KXR 250 ASSEMBLY Install the slow jet. Install the needle jet, needle jet holder and main jet. Install the throttle stop screw and air screw Install the spring, diaphragm and O-rings. • When installing the air screw, return it...

  • Page 78: Engine Removal

    . ENGINE REMOVAL Mongoose/KXR 250 __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ ENGINE REMOVAL __________________________________________________________________________________ SERVICE INFORMATION------------------------------------------------ 6- 1 ENGINE REMOVAL ------------------------------------------------------- 6- 2...
  • Page 79 6. ENGINE REMOVAL/INSTALLATION Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • A floor 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 machine body during engine removal.
  • Page 80 . ENGINE REMOVAL Mongoose/KXR 250 ENGINE REMOVAL Drain engine oil and transmission oil. (Refer to chapter 3) Remove frame covers and exhaust pipe. (Refer chapter 2) Remove the carburetor. (Refer to chapter 5) Disconnect the oil recycle tube at the cylinder head cover.
  • Page 81 6. ENGINE REMOVAL/INSTALLATION Mongoose/KXR 250 Speedometer Cable Disconnect the speedometer cable (ON ROAD only). Drive Sprocket Cover Bolts Remove the three bolts at the drive sprocket cover and then remove the drive sprocket cover. Remove the two bolts on the drive sprocket.
  • Page 82 . ENGINE REMOVAL Mongoose/KXR 250 Gear Change Switch coupler Remove the A.C.Generator, pulser and gear change switch couplers. Pulser coupler A.C.Generator coupler Disconnect the spark plug cap. Spark Plug Cap Bolts Remove the three bolts and remove the outlet hose cover.
  • Page 83 6. ENGINE REMOVAL/INSTALLATION Mongoose/KXR 250 Bolts Remove the two bolts at the left foot peg attaching the left floor board holder and remove the nut at the left floor board holder, then remove the left floor board holder. Reservoir protection Cover Remove the two bolts at the right foot peg attaching the right floor board holder.
  • Page 84 . ENGINE REMOVAL Mongoose/KXR 250 Mounting Bolt and Nut Remove the rear lower mounting bolt and nut. Remove the rear upper mounting bolt and nut. Remove the front mounting bolts and nuts. Mounting Bolt and Nut Mounting Bolt and Nut...
  • Page 85 6. ENGINE REMOVAL/INSTALLATION Mongoose/KXR 250...

  • Page 86: Cylinder Head/Valves

    . CYLINDER HEAD/VALVES Mongoose/KXR 250 __________________________________________________________________________________ CYLINDER HEAD/VALVES SERVICE INFORMATION------------------------------------------------ 7- 2 TROUBLESHOOTING----------------------------------------------------- 7- 3 CYLINDER HEAD COVER----------------------------------------------- 7- 4 CAMSHAFT/CAMSHAFT HOLDER------------------------------------ 7- 4 CYLINDER HEAD---------------------------------------------------------- 7- 9...

  • Page 87: Cylinder Head/Valves

    7. CYLINDER HEAD/VALVES Mongoose/KXR 250...

  • Page 88: Service Information

    . CYLINDER HEAD/VALVES Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • The cylinder head can be serviced with the engine installed in the frame. • When assembling, apply molybdenum disulfide grease or engine oil to the valve guide movable parts, valve arm and camshaft sliding surfaces for initial lubrication.

  • Page 89: Troubleshooting

    7. CYLINDER HEAD/VALVES Mongoose/KXR 250 TORQUE VALUES Cylinder head cover bolt 0.8～1.2kgf-m Cam shaft hold nut 2.3～2.7kgf-m Apply engine oil to threads Tappet adjusting nut 0.7～1.1kgf-m SPECIAL TOOLS Valve spring compressor E040 Tappet adjuster E012 TROUBLESHOOTING • The poor cylinder head operation can be diagnosed by a compression test or by tracing engine top-end noises.

  • Page 90: Cylinder Head Cover

    . CYLINDER HEAD/VALVES Mongoose/KXR 250 Oil Recycle Tube CYLINDER HEAD COVER REMOVAL Remove fuel tank. (Refer to the chapter 5) Disconnect the oil recycle tube at the cylinder head cover. Remove the four bolts at the cylinder head cover, then remove the cylinder head cover.
  • Page 91 7. CYLINDER HEAD/VALVES Mongoose/KXR 250 Remove the four camshaft holder nuts and washers. Diagonally loosen the cylinder head nuts in 2 or 3 times. Remove the camshaft holder and dowel pins. Nuts and Washers Camshaft Holder Camshaft Remove the camshaft gear from the cam chain and remove the camshaft.
  • Page 92 . CYLINDER HEAD/VALVES Mongoose/KXR 250 Camshaft Holder CAMSHAFT HOLDER INSPECTION Inspect the camshaft holder for wear or damage. Inspect the rocker arm shaft for blue discoloration or grooves. If any defects are found, replace the rocker arm shaft with a new one, then inspect lubrication system.
  • Page 93 7. CYLINDER HEAD/VALVES Mongoose/KXR 250 CAMSHAFT HOLDER ASSEMBLY Reverse the “CAMSHAFT HOLDER DISASSEMBLY” procedures. Align the cross cutout on the exhaust valve rocker arm shaft with the bolt of the camshaft holder. Camshaft Bearings CAMSHAFT INSPECTION Check each camshaft bearing for play or damage.
  • Page 94 . CYLINDER HEAD/VALVES Mongoose/KXR 250 INSTALLATION Reverse the “CAMSHAFT REMOVAL” procedures. Note the following points: 1. Turn the flywheel so that the “T” mark on the flywheel aligns with the index mark on the crankcase. Keep the round hole on the camshaft...

  • Page 95: Cylinder Head

    7. CYLINDER HEAD/VALVES Mongoose/KXR 250 Intake Manifold CYLINDER HEAD REMOVE Remove the camshaft. (Refer to the “camshaft remove” section in the chapter 7) Remove the carburetor. (Refer to the “carburetor remove” section in the chapter Remove the exhaust muffler. (Refer to the “exhaust muffler remove”...
  • Page 96 . CYLINDER HEAD/VALVES Mongoose/KXR 250 VALVE /VALVE GUIDE INSPECTION Inspect each valve for bending, burning, scratches or abnormal stem wear. If any defects are found, replace the valve with a new one. Check valve movement in the guide. Measure each valve stem O.D.
  • Page 97 7. CYLINDER HEAD/VALVES Mongoose/KXR 250 Measure 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 specification. Service limits: IN : 0.8mm EX : 1.07mm...
  • Page 98 . CYLINDER HEAD/VALVES Mongoose/KXR 250 ASSEMBLY Install the valve spring seats and oil seal. Be sure to install new oil seal. Lubricate each valve with engine oil and insert the valves into the valve guides. Install the valve springs and retainers.

  • Page 99: Cylinder/Piston

    . CYLINDER/PISTON Mongoose/KXR 250 __________________________________________________________________________________ CYLINDER /PISTON SERVICE INFORMATION------------------------------------------------ 8- 2 TROUBLESHOOTING----------------------------------------------------- 8- 2 CYLINDER/PISTON ------------------------------------------------------- 8- 4...
  • Page 100 . CYLINDER/PISTON Mongoose/KXR 250...
  • Page 101 . CYLINDER/PISTON Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • The cylinder and piston can be serviced with the engine installed in the frame. • After disassembly, clean the removed parts and dry them with compressed air before inspection. TROUBLESHOOTING • When hard starting or poor performance at low speed occurs, check the crankcase breather for white smoke.
  • Page 102 . CYLINDER/PISTON Mongoose/KXR 250 SPECIFICATIONS Standard (mm) Service Limit (mm) I.D. 72.705～72.715 72.8 ⎯ Warpage 0.05 Cylinder ⎯ Cylindricity 0.05 ⎯ True roundness 0.05 Ring-to-groove Top 0.015～0.055 0.09 clearance Second 0.015～0.055 0.09 0.15～0.3 Ring end gap Second 0.3～0.45 0.65 Piston,...
  • Page 103 . CYLINDER/PISTON Mongoose/KXR 250 Cam Chain Guide Gasket CYLINDER/PISTON REMOVAL Remove the cylinder head. (Refer to the chapter 7) Remove the two dowel pins, cylinder head gasket and cam chain guide. Dowel Pins Cylinder Screw Unscrew the clamp and disconnect the water hose.
  • Page 104 . CYLINDER/PISTON Mongoose/KXR 250 INSPECTION Inspect the piston, piston pin and piston rings. Remove the piston rings. Take care not to damage or break the piston rings during removal. Clean carbon deposits from the piston ring grooves. Inspect the piston wall for wear/scratches/damage.
  • Page 105 . CYLINDER/PISTON Mongoose/KXR 250 Measure the piston pin O.D. Service Limit: 16.96mm replace if below Measure the piston O.D. Take measurement at 10mm from the 10 mm bottom and 90° to the piston pin hole. Service Limit: 72.6mm replace if below Measure the piston-to-piston pin clearance.
  • Page 106 . CYLINDER/PISTON Mongoose/KXR 250 PISTON RING INSTALLATION Install the piston rings onto the piston. Apply engine oil to each piston ring. • Be careful not to damage or break the piston and piston rings. • All rings should be installed with the markings facing up.
  • Page 107 . CYLINDER/PISTON Mongoose/KXR 250 “IN” Mark PISTON INSTALLATION Remove any gasket material from the crankcase surface. Be careful not to drop foreign matters into the crankcase. Install the piston, piston pin and a new piston pin clip. • Position the piston “IN” mark on the intake valve side.

  • Page 108: Drive And Driven Pulleys

    DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 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...
  • Page 109 DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250...

  • Page 110: Service Information

    DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • The drive pulley, clutch and driven pulley can be serviced with the engine installed in the frame. • Avoid getting grease and oil on the drive belt and pulley faces. Remove any oil or grease from them to minimize the slipping of drive belt and drive pulley.

  • Page 111: Left Crankcase Cover

    DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 Starting Cover Bolts LEFT CRANKCASE COVER REMOVAL Remove the five bolts. Remove the starting cover. Gasket Remove the dowel pins and gasket. Dowel Pins Outlet Hose Cover Remove the three bolts. Remove the outlet hose cover.

  • Page 112: Drive Pulley

    DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 Bolts Remove the left crankcase cover bolts and left crankcase cover. Remove the gasket and dowel pins. INSPECTION Bearing Inspect the bearing for allow play in the left crankcase cover or the bearing turns roughly →...
  • Page 113 DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 Drive Pulley Collar Remove the movable drive face assembly and drive pulley collar. Drive Face Ramp Plate DISASSEMBLY Remove the ramp plate. Roller Remove the six weight rollers. INSPECTION Check each weight roller for wear or damage.
  • Page 114 DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 Measure the movable drive face bushing I.D. Service Limit: 27.06mm replace if over ASSEMBLY Install the weight rollers into the movable drive face. Install the ramp plate. Check the drive pulley collar for wear or damage.

  • Page 115: Clutch/Driven Pulley

    DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 CLUTCH/DRIVEN PULLEY REMOVAL Remove the left crankcase cover. (Refer to the “LEFT CRANKCASE COVER REMOVAL” section in the chapter 9) Remove the drive pulley. (Refer to the “DRIVE PULLEY REMOVAL” section in the chapter 9) Hold the clutch outer with the universal holder and remove the clutch outer nut.
  • Page 116 DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 CLUTCH OUTER INSPECTION Inspect the clutch outer for wear or damage. Measure the clutch outer I.D. Service Limit: 153.5mm replace if over Clutch Spring Compressor CLUTCH/DRIVEN PULLEY DISASSEMBLY Hold the clutch/driven pulley assembly with the clutch spring compressor.
  • Page 117 DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 Oil Sea Remove the oil seal from the movable driven 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 wear or damage.
  • Page 118 DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 Check the movable driven face for wear or damage. Measure the movable driven face I.D. Service Limit: 40.06mm replace if over Inner Bearing DRIVEN PULLEY FACE BEARING REPLACEMENT Drive the inner needle bearing out of the driven pulley face.
  • Page 119 DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 CLUTCH DISASSEMBLY Circlip Retainer Plate Remove the circlips and retainer plate to disassemble the clutch. Keep grease off the clutch linings. Clutch Lining CLUTCH / DRIVEN PULLEY ASSEMBLY 9-11...
  • Page 120 DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 Install the damper rubbers on the drive plate pins. Install the clutch weights/shoes and clutch springs onto the drive plate. Install the retainer plate and secure with the circlips. Clean the driven pulley faces and remove any grease from them.
  • Page 121 DRIVE AND DRIVEN PULLEYS Mongoose/KXR 250 INSTALLATION Install the clutch/driven pulley and driven belt onto the drive shaft. Keep grease off 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.
  • Page 122 .FINAL REDUCTION/ Mongoose/KXR 250 TRANSMISSION SYSTEM __________________________________________________________________________________ FINAL REDUCTION/TRANSMISSION SYSTEM SERVICE INFORMATION------------------------------------------------ 10- 2 TROUBLESHOOTING----------------------------------------------------- 10- 2 TRANSMISSION CASE COVER--------------------------------------------- 10- 3 TRANSMISSION------------------------------------------------------------ 10- 5 10-0...
  • Page 123 .FINAL REDUCTION/ TRANSMISSION SYSTEM Mongoose/KXR 250 10-1...

  • Page 124: Final Reduction/Transmission System

    .FINAL REDUCTION/ Mongoose/KXR 250 TRANSMISSION SYSTEM SERVICE INFORMATION GENERAL INSTRUCTIONS • The transmission system can be serviced with the engine installed in the frame. • When replacing the drive shaft, use a special tool to hold the bearing inner race for this operation.

  • Page 125: Final Reduction/Transmission System

    .FINAL REDUCTION/ TRANSMISSION SYSTEM Mongoose/KXR 250 Bolts TRANSMISSION CASE COVER REMOVAL Drain transmission gear oil into a clean container. (Refer to the “TRANSMISSION OIL REPLACEMENT” section in the chapter Remove the three and then remove the drive sprocket cover. Drive Sprocket Cover...
  • Page 126 .FINAL REDUCTION/ Mongoose/KXR 250 TRANSMISSION SYSTEM Bearings Transmission Case Cover Remove the transmission case cover, dowel pins and gasket. Inspect the bearings for allow play in the transmission case cover or the bearings turn roughly. If any defects are found, replace the bearing with a new one.

  • Page 127: Transmission

    .FINAL REDUCTION/ TRANSMISSION SYSTEM Mongoose/KXR 250 Needle Bearing Inspect the needle bearing for allow play in the transmission case cover or the bearing turns roughly. If any defects are found, replace the bearing with a new one. Needle Bearing ASSEMBLY Install the needle bearing.
  • Page 128 .FINAL REDUCTION/ Mongoose/KXR 250 TRANSMISSION SYSTEM Remove the stopper plug. Plug Washer Remove spring, washer and shift cam Shift Cam Stopper stopper. Plug Spring Guide Bar Remove the transmission guide bar. Shift Cam Remove shift cam. 10-6...
  • Page 129 .FINAL REDUCTION/ TRANSMISSION SYSTEM Mongoose/KXR 250 Shift Fork Remove the shift fork. Measure the guide bar runout. Out of specification → Replace. Service Limit: Less than 0.03 mm Do not attempt to straighten a bent guide bar. Shift Fork Cam Follower Inspect the shift fork cam follower and shift fork pawl.
  • Page 130 .FINAL REDUCTION/ Mongoose/KXR 250 TRANSMISSION SYSTEM Shift Shaft Inspect shift shaft gear. Damage → Replace. Inspect shift shaft. Damage/bends/wear → Replace. Shift Shaft Gear Remove the main axle. Main Axle Clutch Dog Collar MAIN AXLE DISASSEMBLY Remove the washers, collar, primary driven gear, bush and clutch dog.
  • Page 131 .FINAL REDUCTION/ TRANSMISSION SYSTEM Mongoose/KXR 250 Reverse Wheel Gear Remove the circlip and then remove the washers, reverse wheel gear and needle bearing. Circlip Washer Reverse Wheel Gear Needle Bearing Main Axle Circlip Washers Inspect the gear teeth. Blue discoloration/pitting/wear → Replace.
  • Page 132 .FINAL REDUCTION/ Mongoose/KXR 250 TRANSMISSION SYSTEM MAIN AXLE ASSEMBLY Reverse the “MAIN AXLE DISASSEMBLY” procedures. Reverse Wheel Gear Circlip Clutch Dog Primary Driven Gear Main Axle Washer Washer Washer Needle Bearing Washer Washer Bush Collar 10-10...
  • Page 133 .FINAL REDUCTION/ TRANSMISSION SYSTEM Mongoose/KXR 250 Remove the counter axle. Counter Axle Inspect the gear teeth. Blue discoloration/pitting/wear → Replace. Primary Drive Axle Bolt Oil Seal PRIMARY DRIVE AXLE REMOVAL Remove the clutch/driven pulley. (Refer to the chapter 9) Remove the oil seal, circlip, screw and plate.
  • Page 134 Fill the engine with oil and install the oil filler bolt. (Refer to the “TRANSMISSION OIL REPLACEMENT” section in the chapter Gasket Specified Gear Oil: KYMCO SIGMA GEAR OIL 90# Oil Capacity: At disassembly : 0.4 liter At change : 0.3liter...

  • Page 135: Crankcase/Crankshaft/Balance Shaft

    .CRANKSCASE/CRANKSHAFT/ BALANCE SHAFT Mongoose/KXR 250 __________________________________________________________________________________ CRANKCASE/CRANKSHAFT/BALANCE SHAFT SERVICE INFORMATION------------------------------------------------ 11- 2 TROUBLESHOOTING----------------------------------------------------- 11- 2 CRANKCASE/CRANKSHAFT/BALANCE SHAFT ------------------ 11- 3 11-0...
  • Page 136 .CRANKCASE/CRANKSHAFT/ BALANCE SHAFT Mongoose/KXR 250 11-1...
  • Page 137 .CRANKSCASE/CRANKSHAFT/ BALANCE SHAFT Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • This section covers crankcase separation to service the crankshaft. The engine must be removed for this operation. • The following parts must be removed before separating the crankcase. −Cylinder head ( Chapter 7) −Cylinder/piston ( Chapter 8)
  • Page 138 .CRANKCASE/CRANKSHAFT/ BALANCE SHAFT Mongoose/KXR 250 Timing Chain CRANKCASE/CRANKSHAFT/BA LANCE SHAFT REMOVAL Remove the timing chain from right crankcase. Bolts Remove the left and right crankcase attaching bolts. Separate the left and right crankcase halves. Do not damage the crankcase gasket surface.
  • Page 139 .CRANKSCASE/CRANKSHAFT/ BALANCE SHAFT Mongoose/KXR 250 Balance Shaft Remove balance shaft from the left crankcase. Clean off all gasket material from the crankcase mating surfaces. Avoid damaging the crankcase mating surfaces. Inspect the balance shaft gear teeth. Burrs/chips/roughness/wear → Replace. CRANKSHAFT INSPECTION Inspect the crankshaft gear teeth.
  • Page 140 .CRANKCASE/CRANKSHAFT/ BALANCE SHAFT Mongoose/KXR 250 Measure the connecting rod small end free play (A). Out of specification (0.8 ~ 1.0 mm) → Replace the crankshaft. Measure the crankshaft run out (B). Service Limit: 0.10mm replace if over Measure the connecting rod big end side clearance (C).
  • Page 141 .CRANKSCASE/CRANKSHAFT/ BALANCE SHAFT Mongoose/KXR 250 Mark (Crankshaft) CRANKCASE/BALANCER INSTALLATION Install the balance shaft and crankshaft into the left crankcase. Align the mark on the balance shaft with the mark on the crankshaft. Install the dowel pins and new gasket. Install the right crankcase and tighten the crankcase attach bolts.

  • Page 142: Cooling System

    . COOLING SYSTEM Mongoose/KXR 250 __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ COOLING SYSTEM __________________________________________________________________________________ SERVICE INFORMATION------------------------------------------------ 12- 1 TROUBLESHOOTING----------------------------------------------------- 12- 1 COOLING SYSTEM TESTING------------------------------------------- 12- 3 RADIATOR ------------------------------------------------------------------ 12- 4 WATER PUMP -------------------------------------------------------------- 12- 6 THERMOSENSOR---------------------------------------------------------- 12-10 THERMOSTAT-------------------------------------------------------------- 12-11 12-0...

  • Page 143: Cooling System Testing

    . COOLING SYSTEM Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • The water pump must be serviced after removing the engine. Other cooling system service can be done with the engine installed in the frame. • The engine must be cool before servicing the cooling system.
  • Page 144 1.095 1.093 1.091 1.088 1.085 1.082 1.079 1.076 1.073 1.070 1.067 1.100 1.098 1.095 1.092 1.089 1.086 1.083 1.080 1.077 1.074 1.071 COOLANT MIXTURE (WITH ANTI-RUST AND ANTI-FREEZING EFFECTS) Freezing Point Mixing Rate KYMCO SIGMA Coolant Concentrate Distilled Water 425cc 975cc -44.5 Cautions for Using Coolant: •...
  • Page 145 . COOLING SYSTEM Mongoose/KXR 250 COOLING SYSTEM TESTING RADIATOR CAP INSPECTION Radiator Tester Install the radiator cap onto the radiator tester and apply specified pressure to it. It must hold specified pressure for at least six seconds. Apply water to the cap sealing surface before testing.

  • Page 146: Radiator

    . COOLING SYSTEM Mongoose/KXR 250 Radiator RADIATOR RADIATOR INSPECTION Remove the front fender. ( 2-5) Inspect the radiator soldered joints and seams for leaks. Blow dirt out from between core fins with compressed air. If insects, etc., are clogging the radiator, wash them off.
  • Page 147 . COOLING SYSTEM Mongoose/KXR 250 Bolts RADIATOR DISASSEMBLY Remove the three bolts and then remove the fan/shroud from the radiator. Check fan motor by battery. CHECK THERMOSTATIC SWITCH When coolant temperature lower then 85~90 the thermostatic switch OFF. When coolant temperature over 85~90 the thermostatic switch ON.

  • Page 148: Water Pump

    . COOLING SYSTEM Mongoose/KXR 250 WATER PUMP MECHANICAL SEAL (WATER SEAL) INSPECTION Inspect the telltale hole for signs of mechanical seal coolant leakage. If the mechanical seal is leaking, remove the right crankcase cover and replace the mechanical seal. Water Pump...
  • Page 149 . COOLING SYSTEM Mongoose/KXR 250 Impeller Mechanical Seal Inspect the mechanical (water) seal and seal washer for wear or damage. The mechanical seal and seal washer must be replace as a set. Seal Washer (Porcelain) WATER PUMP SHAFT REMOVAL Remove the water pump impeller. ( 12-6 ) Disconnect the water hose from the right crankcase cover.
  • Page 150 . COOLING SYSTEM Mongoose/KXR 250 Impeller Washer Inner Bearing Snap Ring Remove the water pump shaft outer bearing. Outer Bearing Water Pump Shaft Seal Washer Water Pump Assembly MECHANICAL SEAL REPLACEMENT Drive the mechanical seal out of the water pump assembly from the inside.
  • Page 151 . COOLING SYSTEM Mongoose/KXR 250 Outer Bearing WATER PUMP SHAFT INSTALLATION Drive a new water pump shaft outer bearing into the water pump assembly from the inside. Water Pump Assembly Install the water pump shaft and shaft inner bearing into the waster pump assembly.

  • Page 152: Thermosensor

    . COOLING SYSTEM Mongoose/KXR 250 THERMOSENSOR THERMOSENSOR REMOVAL Drain the coolant. ( 3-20 ) Disconnect the thermosensor wire. Remove the thermosensor from the thermostat. Thermosensor Thermosensor Wire THERMOSENSOR INSPECTION Suspend the thermosensor in a pan of water over a burner and measure the resistance through the sensor as the water heats up.

  • Page 153: Thermostat

    . COOLING SYSTEM Mongoose/KXR 250 Thermostat Bolts Air Vent Tube THERMOSTAT THERMOSTAT REMOVAL Drain the coolant. ( 3-20) Disconnect the thermosensor wire from the thermosensor. Disconnect the water hose from the thermostat housing. Disconnect the air vent tube from the thermostat housing.
  • Page 154 . COOLING SYSTEM Mongoose/KXR 250 THERMOSTAT INSPECTION Suspend the thermostat in a pan of water over a burner and gradually raise the water Thermostat temperature to check its operation. Technical Data Thermometer Begins to open 80±2 Full-open Valve lift 3.5～4.5mm O-ring •...

  • Page 155: Brake System

    . BRAKE SYSTEM Mongoose/KXR 250 __________________________________________________________________________________ BRAKE SYSTEM SERVICE INFORMATION------------------------------------------------ 13- 2 TROUBLESHOOTING----------------------------------------------------- 13- 3 FRONT BRAKE FLUID CHANGE/AIR BLEED ---------------------- 13- 4 BRAKE MASTER CYLINDER -------------------------------------------- 13- 5 FRONT BRAKE CALIPER ------------------------------------------------ 13- 8 REAR HYDRAULIC BRAKE--------------------------------------------- 13-11 REAR BRAKE MASTER CYLINDER (REAR BRAKE PEDAL) ----- 13-13...

  • Page 156: Brake System

    . BRAKE SYSTEM Mongoose/KXR 250 13-1...

  • Page 157: Service Information

    . BRAKE SYSTEM Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • During servicing, keep oil or grease off the brake pads and brake disk. • Drain the brake fluid from the hydraulic brake system before disassembly. • Contaminated brake disk or brake pads reduce stopping power. Clean the contaminated brake disk with high-performance brake degreaser and replace the brake pads.
  • Page 158 . BRAKE SYSTEM Mongoose/KXR 250 FRONT HYDRAULIC BRAKE BRAKE PADS REMOVAL Remove the front wheel. ( 14-3) Remove the two brake pad pins from the brake caliper. Remove the two bolts attaching the brake caliper and then remove brake caliper.

  • Page 159: Front Brake Fluid Change/Air Bleed

    . BRAKE SYSTEM Mongoose/KXR 250 FRONT BRAKE FLUID CHANGE/AIR BLEED BRAKE FLUID DRAINING Place the machine on the level ground and set the handlebar upright. Remove the two screws attaching the brake fluid reservoir cap. Use shop towels to cover plastic parts...

  • Page 160: Brake Master Cylinder

    . BRAKE SYSTEM Mongoose/KXR 250 BRAKE SYSTEM BLEEDING Connect a transparent hose to the bleed valve and fully apply the brake lever after continuously pull it several times. Then, loosen the bleed valve nut to bleed air from the brake system. Repeat these steps until the brake system is free of air.
  • Page 161 . BRAKE SYSTEM Mongoose/KXR 250 Snap Ring Remove the brake lever bolt and the brake lever. Remove the piston rubber cover and snap ring from the brake master cylinder. Snap Ring Pliers (Close) Remove the washer, main piston and spring...
  • Page 162 . BRAKE SYSTEM Mongoose/KXR 250 ASSEMBLY Before assembly, apply brake fluid to all removed parts. • During assembly, the main piston and spring must be installed as a unit without exchange. • When assembling the piston, soak the cups in brake fluid for a while.

  • Page 163: Front Brake Caliper

    . BRAKE SYSTEM Mongoose/KXR 250 FRONT BRAKE CALIPER REMOVAL Remove the front wheel. ( 15-3) First drain the brake fluid from the hydraulic brake system. ( 13-4) Remove the brake pad pins. Remove the brake fluid tube bolt. Remove the two bolts attaching the brake caliper.
  • Page 164 . BRAKE SYSTEM Mongoose/KXR 250 Inner Oil Seal Push the piston oil seal outward to remove Clean the seals groove with brake fluid. Be careful not to damage the piston surface. INSPECTION Inspect the caliper cylinder wall and piston surface for scratch, corrosion or other damages.
  • Page 165 . BRAKE SYSTEM Mongoose/KXR 250 Install the caliper spring plate into the caliper. Make sure that the boss on the caliper correctly engages with the locating slot on the caliper spring plate. INSTALLATION Reverse the “FRONT BRAKE CALIPER REMOVAL” procedures.

  • Page 166: Rear Hydraulic Brake

    . BRAKE SYSTEM Mongoose/KXR 250 Cotter Pin Brake Pad Cover REAR HYDRAULIC BRAKE REAR BRAKE PADS REMOVAL Remove the brake pads cover. Remove the cotter pin and then pull out the brake pad pin from the caliper. Brake Pad Pin...
  • Page 167 . BRAKE SYSTEM Mongoose/KXR 250 Bleed Valve (Front Left Lever) Connect a transparent hose to the brake caliper bleed valve and then loosen the bleed valve nut. Use a syringe to draw the brake fluid out through the hose. Bleed Valve (Pedal)

  • Page 168: Rear Brake Master Cylinder (Rear Brake Pedal)

    . BRAKE SYSTEM Mongoose/KXR 250 REAR BRAKE MASTER CYLINDER (REAR BRAKE PEDAL) REAR MASTER CYLINDER ON THE LEFT HANDGRIP DISASSEMBLY Refer to the “FRONT BRAKE MASTER CYLINDER DISASSEMBLY” section in the chapter 13. ASSEMBLY Refer to the “FRONT BRAKE MASTER CYLINDER ASSEMBLY”...
  • Page 169 . BRAKE SYSTEM Mongoose/KXR 250 Screw Fluid Inlet Duct Remove the screw and remove the fluid inlet duct. Check the O-ring for wear or damage and replace if necessary. O-ring Seal Boot Remove the two nuts and remove the seal boot.
  • Page 170 . BRAKE SYSTEM Mongoose/KXR 250 ASSEMBLY Before assembly, apply brake fluid to all removed parts. During assembly, the master cylinder, piston and spring must be installed as a unit without exchange. Washers Reverse the “MASTER CYLINDER ON THE REAR BRAKE PEDAL DISASSEMBLY”...

  • Page 171: Rear Brake Caliper

    . BRAKE SYSTEM Mongoose/KXR 250 REAR BRAKE CALIPER REMOVAL Drain brake fluid of both the rear brake side and the combination brake side. ( 13-12) To prevent brake fluid from splashing on the parts nearby, cover the parts with cloth.
  • Page 172 . BRAKE SYSTEM Mongoose/KXR 250 INSPECTION Inspect the caliper cylinder wall and piston surface for scratch, corrosion or other damages. If any abnormal condition is noted, replace the caliper. BRAKE DISK Measure the brake disk thickness. Service Limit: 3.0mm Measure the brake disk run out.
  • Page 173 . BRAKE SYSTEM Mongoose/KXR 250 O-ring Fit the O-ring. Install and tighten the caliper housing bolts. Torque: 1.8～2.5kgf-m Washers 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.

  • Page 174: Front Wheel/Front Suspension/Steering System

    FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 __________________________________________________________________________________ FRONT WHEEL/ FRONT SUSPENSION\STEERING SYSTEM SERVICE INFORMATION------------------------------------------------ 14- 2 TROUBLESHOOTING----------------------------------------------------- 14- 2 FRONT WHEEL------------------------------------------------------------- 14- 3 FRONT WHEEL HUB------------------------------------------------------ 14- 4 FRONT SUSPENSION ----------------------------------------------------- 14- 8 TIE-ROD---------------------------------------------------------------------- 14-12 HANDLEBAR --------------------------------------------------------------- 14-14 STEERING COLUMN------------------------------------------------------ 14-16...

  • Page 175: Front Wheel/ Front Suspension\Steering System

    FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 14-1...

  • Page 176: Service Information

    FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • Jack the machine front wheel off the ground and be careful to prevent the machine from falling down. • During servicing, keep oil or grease off the brake disk •...
  • Page 177 FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Nuts FRONT WHEEL REMOVAL AND INSPECTION Place the machine on a level place. Remove four nuts attaching the front wheel hub and front wheel. Elevate the front wheels by placing a suitable stand under the frame.

  • Page 178: Front Wheel Hub

    FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Nuts Cotter Pin FRONT WHEEL HUB REMOVAL AND INSPECTION Place the machine on a level place. Remove the front wheel ( 14-3) and caliper. ( 13-8) Elevate the front wheels by placing a suitable stand under the frame.
  • Page 179 FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Bearing If any defects are found, replace the bearings Remove the bearings using a general bearing puller. Distance Collar Remove the distance collar from the front wheel hub. ASSEMBLY Install the left new bearing and dust seal into the front wheel hub.
  • Page 180 FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Distance Collar Install the distance collar. Be sure the tapered side of the distance collar face the wheel. Install the right new bearing and dust seal into the front wheel hub. Apply the grease onto the oil seal lips, bearing.
  • Page 181 FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Install the cotter pin and band ends of 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 groove with the hole by tightening up on the wheel hub nut.

  • Page 182: Front Suspension

    FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 FRONT SUSPENSION REMOVAL AND INSPECTION Elevate the front wheels by placing a suitable stand under the frame. Support the machine securely so there is no danger of it falling over. Remove the front wheel ( 14-3), caliper ( 13-8) and front wheel hub.
  • Page 183 FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Inspect the shock absorber rod. Bush Bends/damage →Replace the shock absorber assembly. Inspect the shock absorber. Oil leaks →Replace the shock absorber assembly. Inspect the spring of the shock absorber by move the spring up and down.
  • Page 184 FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Bushes Inspect the front arm. Cracks/bends/damage →Replace. Do not attempt to straighten a bent arm, this may dangerously weaken the arm. Inspect bushes. Wear/damage →Replace. Check the lower front arm brackets of the frame.
  • Page 185 FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Bushes Inspect the lower front arm. Cracks/bends/damage →Replace. Do not attempt to straighten a bent arm, this may dangerously weaken the arm. Inspect bushes. Wear/damage →Replace. INSTALLATION Reverse the “FRONT SUSPENSION REMOVAL AND INSPECTION”...

  • Page 186: Tie-Rod

    FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 TIE-ROD REMOVAL AND INSPECTION Remove the cotter pin and nut attaching the tie-rod and steering column. Remove the cotter pin and nut attaching the tie-rod and steering knuckle. Then remove tie-rods. Cotter Pin Cotter Pin Inspect the tie-rod.
  • Page 187 FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 To Knuckle Arm Set the rod-end (steering column side) in an angle where the indentation surface of the tie-rod is parallel to the rod-end shaft, and then tighten the lock nut. Torque: 2.5～3.5kgf-m...

  • Page 188: Handlebar

    FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 HANDLEBAR REMOVAL AND INSPECTION Remove the following parts: Seat, front cover, center cover, front fender and handlebar cover. Refer to the “FENDERS” section in the CHAPTER 2 Remove the right and left master cylinder...
  • Page 189 FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Holder Surface INSTALLATION Install handlebar and handlebar holder, then tighten the four bolts. Torque: 1.8～2.5kgf-m • Align the mark on the handlebar with the lower handlebar holder surface. • Be sure the upper handlebar holder mark face to front.

  • Page 190: Steering Column

    FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Install the throttle unit by aligning the upper Mark holder lip with the mark in the handlebar and then install the lower holder and tighten the two screws. Upper Holder Lip Steering Bracket...
  • Page 191 FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Remove the cotter pins and nuts attaching the tie-rods, then disconnect the tie-rods from the steering column. Cotter Pin Remove the cotter pin and nut attaching the steering column under the frame body, then remove steering column and collar.
  • Page 192 FRONT WHEEL/FRONT SUSPENSION/ STEERING SYSTEM Mongoose/KXR 250 Inspect the steering column. Bends/damage →Replace. Do not attempt to straighten a bent shaft, this may dangerously weaken the shaft. Inspect the steering brackets and oil seal. Wear damage →Replace. INSTALLATION Reverse the “REMOVAL” procedures.

  • Page 193: Rear Wheel/Axle/Suspension

    Mongoose/KXR 250 . REAR WHEEL/AXLE/SUSPENSION __________________________________________________________________________________ REAR WHEEL/AXLE/SUSPENSION SERVICE INFORMATION------------------------------------------------ 15- 2 TROUBLESHOOTING----------------------------------------------------- 15- 3 REAR WHEEL/AXLE/AXLE HUB -------------------------------------- 15- 3 REAR FORK/SWIM ARM/SHOCK ABSORBER --------------------- 15- 12 15-0...

  • Page 194: Rear Wheel/Axle/Suspension

    . REAR WHEEL/AXLE/SUSPENSION Mongoose/KXR 250 15-1...

  • Page 195: Service Information

    Mongoose/KXR 250 . REAR WHEEL/AXLE/SUSPENSION SERVICE INFORMATION GENERAL INSTRUCTIONS • Jack the machine front wheel off the ground and be careful to prevent the machine from falling down. • During servicing, keep oil or grease off the brake disk • Inspect the brake system before riding.

  • Page 196: Rear Wheel/Axle/Axle Hub

    . REAR WHEEL/AXLE/SUSPENSION Mongoose/KXR 250 Rear Axle Nuts REAR WHEEL/AXLE/AXLE REMOVAL AND INSPECTION Place the machine on a level place. Remove the rear caliper. (Refer to the “REAR BRAKE CALIPER REMOVAL” section in chapter 13) Use the nut wrench to loosen two rear axle nuts (inner and outer) of the rear axle.
  • Page 197 Mongoose/KXR 250 . REAR WHEEL/AXLE/SUSPENSION 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 Collar Washer inner), washer and collar. Rear Axle Nuts Remove the rear brake disk.
  • Page 198 . REAR WHEEL/AXLE/SUSPENSION Mongoose/KXR 250 Inspect the brake disk Cracks/damage → Replace. Inspect the brake disk splines. Wear/damage → Replace. Splines Drive Sprocket Cover Bolts Loosen the driven chain (refer to the “DRIVE CHAIN SLACK ADJUSTMENT” section in the chapter 3) and remove the two...
  • Page 199 Mongoose/KXR 250 . REAR WHEEL/AXLE/SUSPENSION REAR AXLE DISASSEMBLY Remove the driven sprocket clip at the rear axle and then remove the driven sprocket. Clip Remove the four nuts attaching the driven sprocket holder at the driven sprocket and then remove driven sprocket.
  • Page 200 . REAR WHEEL/AXLE/SUSPENSION Mongoose/KXR 250 Inspect the driven sprocket holder splines. Wear/damage → Replace. Splines Inspect the rear axle. Scratched (excessively)/damage → Replace. Inspect the splines and threads of the rear axle Wear/damage → Replace. Measure the rear axle run out.
  • Page 201 Mongoose/KXR 250 . REAR WHEEL/AXLE/SUSPENSION Collar Circlip Remove the circlip at the caliper holder and then remove the caliper holder and collar. Caliper Holder Remove the rear axle hub from right side. Rear Axle Hub 15-8...
  • Page 202 . REAR WHEEL/AXLE/SUSPENSION Mongoose/KXR 250 Inspect rear axle hub. Bearings allow play in the axle hub or the bearing turns roughly → Replace. Oil seals is wear/damage → Replace. Axle hub is cracks/bend/damage → Replace. Dust Seal REAR AXLE HUB DISASSEMBLY Bearing and dust seal replacement steps: Clean the outside of the rear axle hub.
  • Page 203 Mongoose/KXR 250 . REAR WHEEL/AXLE/SUSPENSION INSTALLATION Reverse the “REAR WHEEL/AXLE/AXLE HUB REMOVAL AND INSPECTION” procedures. Apply grease onto the dust seal lips and bearings. Install the rear axle hub. At this time, the rear axle hub should not be tightened completely.
  • Page 204 . REAR WHEEL/AXLE/SUSPENSION Mongoose/KXR 250 Install the rear wheel and tighten the four nuts. Torque: 4.0～5.0kgf-m Be sure the tapered side of the wheel nuts face the wheel rim. Tighten the two rear axle nuts (inner and outer). Note that the rear axle nuts are left threaded.

  • Page 205: Rear Fork/Swim Arm/Shock Absorber

    Mongoose/KXR 250 . REAR WHEEL/AXLE/SUSPENSION REAR FORK/SWIM ARM/SHOCK ABSORBER REMOVAL AND INSPECTION Place the machine on a level place. Elevate the rear wheels by placing a suitable stand under the rear of frame. Support the machine securely so there is no danger of it falling over.
  • Page 206 . REAR WHEEL/AXLE/SUSPENSION Mongoose/KXR 250 Bolts Remove the two bolts attaching the rear swing arm at the rear fork and then remove the rear swing arm. Rear Swim Arm Bush Inspect the shock absorber rod. Bends/damage → Replace the shock absorber assembly.
  • Page 207 Mongoose/KXR 250 . REAR WHEEL/AXLE/SUSPENSION Dust Seals Dust Seal Bushes Remove the dust seals and the bushes from the lower rear swing arm. Inspect the lower rear swing arm. Wear/damage → Replace. Inspect the bush. Wear/damage → Replace. Lower Rear Swing Arm...
  • Page 208 . REAR WHEEL/AXLE/SUSPENSION Mongoose/KXR 250 Check the rear fork vertical movement by moving it up and down. If vertical movement is tight, binding or rough, check the inner collar, bearing, bushing and thrust cover, or adjust the shim. Band Remove the band and then disconnect the rear brake fluid tubes from the rear fork.
  • Page 209 Mongoose/KXR 250 . REAR WHEEL/AXLE/SUSPENSION Thrust Covers Inspect the rear fork. Crack/bend/damage → Replace. Roll the axle on a flat surface to inspect the pivot shaft. Bends → Replace. Do not attempt to straighten a bent axle. Inspect the thrust covers, collar and bushes.
  • Page 210 . REAR WHEEL/AXLE/SUSPENSION Mongoose/KXR 250 INSTALLATION Reverse the “REAR FORK/SWIM ARM/SHOCK ABSORBER REMOVAL AND INSPECTION” procedure. Apply grease onto the collar, bush, pivot shaft and thrust cover. Install the rear fork and tightening the nut and pivot shaft. Torque: 6.0～8.0kgf-m Install the rear swing arm and tightening the bolts.

  • Page 211: Generator

    . BATTERY/CHARGING SYSTEM/ A.C. GENERATOR Mongoose/KXR 250 __________________________________________________________________________________ BATTER/CHARGING SYSTEM/ A.C. GENERATOR SERVICE INFORMATION------------------------------------------------ 16- 2 TROUBLESHOOTING----------------------------------------------------- 16- 3 BATTERY REMOVAL ---------------------------------------------------- 16- 4 CHARGING SYSTEM ----------------------------------------------------- 16- 6 REGULATOR/RECTIFIER------------------------------------------------ 16- 7 A.C. GENERATOR CHARGING COI ---------------------------------- 16- 8 16-0...

  • Page 212: Batter/Charging System

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

  • Page 213: Service Information

    . BATTERY/CHARGING SYSTEM/ A.C. GENERATOR Mongoose/KXR 250 SERVICE INFORMATIONN GENERAL INSTRUCTIONS The battery electrolyte (sulfuric acid) is poisonous and may seriously damage the skin and eyes. Avoid contact with skin, eyes, or clothing. In case of contact, flush with water and get prompt medical attention •...

  • Page 214: Troubleshooting

    . BATTERY/CHARGING SYSTEM/ A.C. GENERATOR Mongoose/KXR 250 TESTING INSTRUMENTS Electric tester TROUBLESHOOTING No power Intermittent power • Dead battery • Loose battery cable connection • Disconnected battery cable • Loose charging system connection • Fuse burned out • Loose connection or short circuit in •...

  • Page 215: Battery Removal

    . BATTERY/CHARGING SYSTEM/ A.C. GENERATOR Mongoose/KXR 250 Seat Lock Lever BATTERY REMOVAL Pull right the lock lever and pull up the seat at the rear. Remove the battery holder, by removing the mount bolts. (Make sure the ignition switch is oFF) Remove the battery by removing the bolt.
  • Page 216 . BATTERY/CHARGING SYSTEM/ A.C. GENERATOR Mongoose/KXR 250 CHARGING Connect the charger positive (+) cable to the battery positive (+) terminal. Connect the charger negative (-) cable to the battery negative (-) terminal. • Keep flames and sparks away from a charging battery.

  • Page 217: Charging System

    . BATTERY/CHARGING SYSTEM/ A.C. GENERATOR Mongoose/KXR 250 CHARGING SYSTEM SHORT CIRCUIT TEST Disconnect the ground wire from the battery and connect an ammeter across the battery negative (-) terminal and the ground wire. Turn the ignition switch OFF and check for short circuit.

  • Page 218: Regulator/Rectifier

    . BATTERY/CHARGING SYSTEM/ A.C. GENERATOR Mongoose/KXR 250 Regulator/Rectifier Couplers REGULATOR/RECTIFIER INSPECTION Remove the front fender. ( Refer to chapter Remove the regulator/rectifier wire coupler. Check the continuity between the wire terminals. Lock Nut Regulator/Rectifier Normal Direction: Continuity Normal Red/White Direction...
  • Page 219 . BATTERY/CHARGING SYSTEM/ A.C. GENERATOR Mongoose/KXR 250 A.C. GENERATOR INSPECTION This test can be made without removing the stator from the engine. Disconnect the A.C. generator connector. Check the continuity between the yellow wires and ground. There should be continuity between the yellow wires and no continuity between each yellow wire and ground.
  • Page 220 . BATTERY/CHARGING SYSTEM/ A.C. GENERATOR Mongoose/KXR 250 Flywheel Puller Remove the flywheel with a flywheel puller. Special Flywheel puller E003 INSTALLATION Reverse the “REMOVAL” procedures. Install the flywheel, washer and tighten the nut. Torque: 5.5～6.5kgf-m ‧Before installation, check and make sure that the inside of the flywheel is not contaminated.
  • Page 221 . IGNITION SYSTEM Mongoose/KXR 250 __________________________________________________________________________________ IGNITION SYSTEM SERVICE INFORMATION------------------------------------------------ 17- 2 TROUBLESHOOTING----------------------------------------------------- 17- 3 IGNITION UNIT /CHANGE GEAR CONTROL INSPECTION----- 17- 4 IGNITION COIL INSPECTION------------------------------------------- 17- 6 PULSER COIL --------------------------------------------------------------- 17- 7 17-0...

  • Page 222: Ignition System

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

  • Page 223: Service Information

    . IGNITION SYSTEM Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • Check the ignition system according to the sequence specified in the Troubleshooting. • The ignition system adopts ignition unit, change gear control and the ignition timing cannot be adjusted. • If the timing is incorrect, inspect the ignition unit, A.C. generator, change gear control and replace any faulty parts.

  • Page 224: Troubleshooting

    . IGNITION SYSTEM Mongoose/KXR 250 TROUBLESHOOTING High voltage too low No high voltage • Weak battery or low engine speed • Faulty ignition switch • Loose ignition system connection • Faulty ignition unit • Faulty ignition unit • Poorly connected or broken ignition unit ground wire •...

  • Page 225: Ignition Unit /Change Gear Control Inspection

    . IGNITION SYSTEM Mongoose/KXR 250 Ignition Unit IGNITION UNIT /CHANGE GEAR CONTROL INSPECTION Remove the seat. (Refer to the chapter 2) Disconnect the ignition unit coupler and remove the ignition unit. Disconnect the change gear control coupler and remove the change gear control.
  • Page 226 . IGNITION SYSTEM Mongoose/KXR 250 Test the ignition unit using the ignition unit tester. CDI Tester Ignition Coil Operate the ignition unit tester by Spark following the manufacturer‘s Window instructions. Connect the special connector to the ignition unit coupler and ignition unit tester.

  • Page 227: Ignition Coil Inspection

    . IGNITION SYSTEM Mongoose/KXR 250 IGNITION COIL INSPECTION CONTINUITY TEST Remove the front fender. (Refer to the chapter 2) Remove the spark plug cap. (Refer to the chapter 6) Disconnect the ignition coil wires. This test is to inspect the continuity of ignition coil.

  • Page 228: Ignition System

    . IGNITION SYSTEM Mongoose/KXR 250 PERFORMANCE TEST CDI Tester Ignition Coil Test the performance with a ignition unit tester. • Operate the ignition unit tester by following the manufacturer‘s instructions. • Use the special connector to connect the ignition unit.

  • Page 229: Starting System

    . STARTING SYSTEM Mongoose/KXR 250 __________________________________________________________________________________ STARTING SYSTEM SERVICE INFORMATION------------------------------------------------ 18- 2 TROUBLESHOOTING----------------------------------------------------- 18- 2 STARTER MOTOR --------------------------------------------------------- 18- 3 STARTER RELAY---------------------------------------------------------- 18- 6 STARTER CLUTCH-------------------------------------------------------- 18- 7 18-0...
  • Page 230 . STARTING SYSTEM Mongoose/KXR 250 Starter Button Stop Switches Fuse/Battery/Starter Relay Ignition S it h Starter Motor STARTING CIRCUIT 18-1...

  • Page 231: Starting System

    . STARTING SYSTEM Mongoose/KXR 250 SERVICE INFORMATION GENERAL INSTRUCTIONS • The removal of starter motor can be accomplished with the engine installed. TROUBLESHOOTING Starter motor won‘t turn Lack of power • Fuse burned out • Weak battery • Weak battery •...

  • Page 232: Starter Motor

    . STARTING SYSTEM Mongoose/KXR 250 Rubber Jacket Bolts STARTER MOTOR REMOVAL Before removing the starter motor, turn the ignition switch OFF and remove the battery ground. Then, turn on the ignition switch and push the starter button to see if the starter motor operates properly.
  • Page 233 . STARTING SYSTEM Mongoose/KXR 250 STARTER MOTOR CASE CONTINUITY CHECK Check to confirm that there is no continuity between the starter motor wire terminal and the motor front cover. Also check for the continuity between the wire terminal and each brush.
  • Page 234 . STARTING SYSTEM Mongoose/KXR 250 Commutator ASSEMBLY Apply grease to the dust seal in the front cover. Install the brushes onto the brush holders. Apply a thin coat of grease to the two ends of the armature shaft. Insert the commutator into the front cover.

  • Page 235: Starter Relay

    . STARTING SYSTEM Mongoose/KXR 250 Starter Relay STARTER RELAY INSPECTION Remove the seat. (Refer to the chapter 2) Turn the ignition switch ON and the starter relay is normal if you hear a click when the starter button is depressed.

  • Page 236: Starter Clutch

    . STARTING SYSTEM Mongoose/KXR 250 STARTER CLUTCH REMOVAL Remove the right crankcase cover. (Refer to the “WATER PUMP SHAFT REMOVAL” section in the chapter 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.
  • Page 237 . STARTING SYSTEM Mongoose/KXR 250 Starter Idle Gear Inspect the starter idle gear and shaft for wear or damage. Starter Idle Gear Shaft INSTALLATION Reverse the “REMOVAL” procedures. Install the starter idle gear and shaft. Install the starter driven gear.

  • Page 238: Bulbsremoval/Instrument/ Horn

    . BULBS REMOVAL/INSTRUMENT/HORN Mongoose/KXR 250 __________________________________________________________________________________ BULBS REMOVAL/INSTRUMENT/HORN BULBS REMOVAL--------------------------------------------------------- 19- 1 INSTRUMENT (ON ROAD ONLY) ------------------------------------- 19- 4 HORN (ON ROAD ONLY) ------------------------------------------------ 19- 4 19-0...
  • Page 239 . BULBS REMOVAL/INSTRUMENT/HORN Mongoose/KXR 250 Headlight Wire Coupler BULBS REMOVAL HEADLIGHT Remove the front fender. (See page 2-5) Disconnect the headlight wire coupler. Remove the rubber boot from the bulb socket. Relax the lock clip to remove the bulb and replace with a new one.
  • Page 240 . BULBS REMOVAL/INSTRUMENT/HORN Mongoose/KXR 250 Bulb Socket Bulb INDICATOR LIGHT Remove the handlebar cover. (See page 2-4) Remove the bulb sockets by pulling them out. Remove the bulb. Install the bulb in the reverse order of removal. Bulb Socket Bulb POSITION LIGHT (ON ROAD ONLY) Remove the handlebar cover.
  • Page 241 . BULBS REMOVAL/INSTRUMENT/HORN Mongoose/KXR 250 Install the bulb socket, aligning the bulb socket groove with the turn signal case tab. Install the turn signal lens, aligning the turn signal lens groove with the turn signal case tab. Bule Screw REAR TURN SIGNAL LIGHT (ON...
  • Page 242 . BULBS REMOVAL/INSTRUMENT/HORN Mongoose/KXR 250 Instrument INSTRUMENT (ON ROAD) REMOVAL Remove the handlebar cover. (See page 2-4) Disconnect the meter wire coupler and speedometer cable. Remove the two nuts and then remove the instrument. Meter Wire Speedometer Cable Nuts Pull the bulb socket out and then remove the instrument bulb.

This manual is also suitable for:

Mongoose 250Kxr 250

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