2022 Kawasaki KX250 Troubleshooting Guide

2022 Kawasaki KX250 Troubleshooting Guide

Troubleshooting Guide

NOTE
This troubleshooting guide is not exhaustive and does not give every possible cause for each problem listed. t is meant simply as a quick guide to assist you in troubleshooting for some of the more common difficulties.

Starting failure or difficulties

The starter motor does not rotate:

• Main switch not “ON” position
• Starter lockout switch trouble
• Starter motor trouble
• Battery voltage low
• Starter relay not contacting or operating
• Starter button not contact
• Starter system wiring shorted or open
• Engine stop button trouble
• Main fuse 20 A blown

Starter motor rotating but the engine does not turn over:

• Starter clutch trouble
• Starter idle gear trouble

The engine does not turn over:

• Valve seized
• Rocker arm seized
• Cylinder or piston seized
• Crankshaft seized
• Connecting rod small end seized
• Connecting rod big end seized
• Camshaft seized
• Transmission gear or bearing seized
• Improper installation of the vehicle-down sensor

Fuel does not flow

• No fuel in tank
• Fuel tank cap air vent obstructed
• Fuel line clogged
• Brake down of a fuel pump
• Brake down of a fuel injector

Spark missing or weak:

• Spark plug dirty, broken, or gap improperly adjusted
• Spark plug cap or high-tension wiring defective
• Spark plug cap not contacting properly
• Spark plug type incorrect
• Crankshaft sensor defective
• ECU defective
• Ignition coil defective
• Engine stop button wiring defective
• Alternator damaged
• Wiring shorted or interrupted

Compression low:

• Spark plug loose
• Cylinder head insufficiently tightened
• Cylinder or piston worn
• No valve clearance
• Crankshaft oil seal leak
• Valve spring broken or weak
• Valve not seating properly (valve bent, worn, or carbon accumulation on the seating surface)
• Piston ring worn, weak, broken, or sticking
• Piston ring side clearance excessive
• Cylinder head gasket damaged
• Cylinder head warped
• Cylinder gasket damaged
• Decompression trouble

Poor low-speed performance

Spark weak:

• Spark plug dirty, broken, or gap improperly adjusted
• Spark plug cap or high-tension wiring defective
• Spark plug cap shorted or not contacting properly
• Spark plug type incorrect
• ECU defective
• Ignition coil defective
• Crankshaft sensor defective
• Alternator defective
• Wiring connector not in good contact

Fuel/air mixture incorrect:

• Air cleaner element clogged, poorly sealed, or not installed
• Fuel tank cap air vent obstructed
• Throttle body assy holder loose
  Air cleaner duct loose
  Fuel pump defective

Compression low:

• Spark plug loose
• Cylinder head insufficiently tightened
• Cylinder or piston worn
• No valve clearance
• Valve spring broken or weak
• Valve not seating properly (valve bent, worn, or carbon accumulation on the seating surface)
• Piston ring worn, weak, broken, or sticking
• Piston ring side clearance excessive
• Cylinder head gasket damaged
• Cylinder head warped
• Cylinder gasket damaged
• Decompression trouble

Other:

• ECU defective
• Brake dragging
• Clutch slipping
• Engine over heating
• Engine oil level too high
• Engine oil viscosity too high
• Drive chain trouble

Poor or no high-speed performance

Firing incorrect:

• Spark plug dirty, broken, or gap improperly adjusted
• Spark plug cap or ignition coil defective
• Spark plug cap shorted or not contacting properly
• Spark plug type incorrect
• ECU defective
• Crankshaft sensor defective
• Alternator defective
• Wiring connector not in good contact

Fuel/air mixture incorrect:

• Air cleaner element clogged, poorly sealed, or not installed
• Fuel contaminated with water or foreign matter
• Fuel tank cap air vent obstructed
• Throttle body assy holder lose
• Air cleaner duct lose
• Fuel line clogged
• Fuel pump defective

Compression low

• Spark plug loose
• Cylinder head was insufficiently tightened
• Cylinder or piston worn
• No valve clearance
• Valve spring broken or weak
• Valve not seating properly (valve bent, worn, or carbon accumulation on the seating surface)
• Piston ring worn, weak, broken, or sticking
• Piston ring side clearance excessive
• Cylinder head gasket damaged
• Cylinder head warped
• Cylinder gasket damaged
• Decompression trouble

Improper acceleration

• Throttle valve does not fully open
• Air cleaner element clogged
• Muffler clogged
• Fuel contaminated with water or foreign matter
• Brake dragging
• Clutch slipping
• Engine overheating
• Engine oil level too high
• Engine oil viscosity too high
• Crankshaft bearing worn or damaged
• Crankshaft sensor defective

Knocking:

• Carbon built up in combustion chamber
• Fuel quality poor or type incorrect
• Spark plug type incorrect
• ECU defective

Engine overheating

Firing incorrect:

• Spark plug dirty, broken, or gap improperly adjusted
• Spark plug type incorrect
• ECU defective

Fuel/air mixture incorrect:

• Throttle body assy holder loose
• Air cleaner element clogged, poorly sealed, or not installed
• Air cleaner duct poorly sealed

Compression high:

• Carbon built up in combustion chamber

Engine overloaded:

• Brake dragging
• Clutch slipping
• Engine oil level too high
• Engine oil viscosity too high
• Drive chain trouble

Lubrication inadequate:

• Engine oil level too low
• Engine oil quality poor or type incorrect

Coolant inadequate:

• Coolant level too low
• Coolant deteriorated
• Cooling system component defective:
• Radiator clogged
• Radiator cap defective
• Water pump not rotating

Clutch operation faulty

Clutch slipping:

• No clutch lever play
• Clutch cable improperly adjusted
• Clutch cable defective
• Clutch plate worn or warped
• Clutch spring broken or weak
• Clutch release mechanism defective
• Clutch hub or housing unevenly worn

Clutch not disengaging properly:

• Clutch lever play excessive
• Clutch spring tension uneven
• Engine oil deteriorated
• Engine oil viscosity too high
• Engine oil level too high
• Clutch housing frozen on drive shaft
• Clutch release mechanism defective
• Clutch hub nut loose
• Clutch plate warped or rough
• Clutch hub spline damaged

Gear shifting faulty

Transmission does not go into gear; shift pedal does not return:

• Clutch not disengaging
• Shift fork bent or seized
• Gear stuck on the shaft
• Shift mechanism arm spring broken
• Shift mechanism arm broken
• Shift return spring broken or weak
• Shift return spring pin loose
• Shift pawl broken
• Shift drum broken
• Gear positioning lever operation defective

Transmission jumps out of gear

• Shift fork worn
• Gear groove worn
• Gear dogs and/or dog grooves worn
• Shift drum groove worn
• Gear positioning lever spring broken or weak
• Shift fork pin worn
• Drive shaft, output shaft, and/or gear splines worn

Transmission skips gears:

• Gear positioning lever spring broken or weak
• Shift mechanism arm spring broken or weak

Engine noise abnormal

Knocking:

• Carbon built up in combustion chamber
• Fuel quality poor or type incorrect
• Spark plug type incorrect
• Engine overheating
• ECU defective

Piston slap:

• Piston clearance excessive
• Cylinder or piston worn
• Connecting rod bent
• Piston pin or piston pin holes worn

Valve noise:

• Valve clearance incorrect
• Valve spring broken or weak
• Camshaft bearing or cam face worn
• Rocker arm worn

Other noise:

• Connecting rod small end clearance excessive
• Connecting rod big end clearance excessive
• Piston ring worn, broken or stuck
• Piston seized or damaged
• Cylinder head gasket leaking
• Exhaust pipe leaking at cylinder head
• Crankshaft runout excessive
• Engine mounts loose
• Crankshaft bearing worn
• Camshaft chain tensioner trouble
• Camshaft chain, sprocket, chain guide worn
• Alternator rotor loose

Abnormal drive train noise

Clutch noise:

• Clutch housing/friction plate clearance excessive
• Clutch housing gear excessive
• Metal chip jammed in clutch housing gear teeth

Transmission noise

• Crankcase bearing worn or damaged
• Transmission gear worn or chipped
• Metal chip jammed in gear teeth
• Engine oil level or viscosity too low

Drive chain noise:

• Drive chain slack improperly adjusted
• Drive chain worn
• Rear and/or engine sprocket(s) worn
• Drive chain inefficiently lubrified
• Rear wheel misaligned

Frame noise abnormal

Front fork noise:

• Oil level or viscosity too low
• Spring broken or weak

Rear shock absorber noise:

• Shock absorber damaged

Disc brake noise:

• Pad installed incorrectly
• Pad surface glazed
• Brake disc warped
• Brake caliper defective
• Brake cylinder damaged

Other noise:

• improperly mounted or Bracket, nut, bolt, etc. tightened

Exhaust smoke

Excessively white:

• Piston oil ring worn
• Cylinder worn
• Valve oil seal damaged
• Valve guide worn
• Engine oil level too high

Black smoke:

• Air cleaner element clogged

Brownish:

• Air cleaner duct loose
• Air cleaner poorly sealed or missing

Poor handling and/or stability

Handlebar hard to turn:

• Cable, hose, wiring incorrectly routed
• Steering stem nut too tight
• Steering stem bearing damaged
• Steering stem bearing inadequately lubricated
• Steering stem bent
• Tire air pressure too low

Handlebar shakes or vibrates excessively:

• Tire won
• Swingarm sleeve or needle bearing damaged
• Rim warped or out of balance
• Front and/or rear axle runout excessive
• Wheel bearing worn
• Handlebar clamp loose
• Steering stem head nut loose
• Spoke loose

Handlebar pulls to one side:

• Frame bent
• Rear wheel misaligned
• Swingarm bent or twisted
• Swingarm pivot shaft runout excessive
• Steering maladjusted
• Steering stem bent
• Front fork bent
• Right/left front fork oil level uneven

Shock absorption unsatisfactory (suspension too hard):

• Front fork oil excessive
• Front fork oil viscosity too high
• Front fork bent
• Tire air pressure too high
• Rear shock absorber was improperly adjusted

Shock absorption unsatisfactory (suspension too soft):

• Front fork oil level insufficient and/or front fork leaking oil
• Front fork oil viscosity too low
• Front fork and/or rear shock absorber spring weak
• Rear shock absorber leaking oil or gas
• Rear shock absorber was improperly adjusted
• Tire air pressure too low

Poor braking performance

• Air in the brake line
• Brake pad or disc worn
• Brake fluid leakingg
• Brake disc warped
• Brake pads contaminated
• Brake fluid deteriorated
• Brake master cylinder primary and/or secondary cup(s) damaged
• Brake master cylinder scratched
• Brake maladjusted (lever or pedal play excessive)

Battery trouble

Battery discharged:

• Charge insufficient
• Battery faulty (too low terminal voltage)
• Battery cable making poor contact
• Alternator trouble
• Wiring faulty
• Regulator trouble

Battery overcharged:

• Alternator magneto trouble
• Regulator trouble
• Battery faulty