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Trouble Shooting Guide


BudgetBoy

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Thought this guide might help some people so i'm posting it up.Sticky it if it might help others.

Engine Doesn’t Start, Starting Difficulty:

Starter motor not rotating:

Starter lockout or neutral switch trouble

Starter motor trouble

Battery voltage low

Relays not contacting or operating

Starter button not contacting

Wiring open or shorted

Ignition switch trouble

Engine stop switch trouble

Main fuse blown

Starter motor rotating but engine doesn’t turn over:

Starter motor clutch trouble

Engine won’t turn over:

Valve seizure

Rocker arm seizure

Cylinder, piston seizure

Crankshaft seizure

Connecting rod small end seizure

Connecting rod big end seizure

Transmission gear or bearing seizure

Camshaft seizure

No fuel flow:

Fuel tap vacuum hose clogged

Fuel tank air vent obstructed

Fuel tap clogged

Fuel line clogged

Float valve clogged

Engine flooded:

Fuel level in carburetor float bowl too high

Float valve worn or stuck open

Starting technique faulty

(When flooded, crank the engine with the throttle fully open to allow more air to reach the engine.)

No spark; spark weak:

Battery voltage low

Spark plug dirty, broken, or maladjusted

Spark plug cap or high tension wiring trouble

Spark plug cap not in good contact

Spark plug incorrect

IC igniter trouble

Neutral, starter lockout, or side stand switch trouble

Pickup coil trouble

Ignition coil trouble

Ignition or engine stop switch shorted

Wiring shorted or open

Main fuse blown

Compression Low:

Spark plug loose

Cylinder head not sufficiently tightened down

No valve clearance

Cylinder, piston worn

Piston ring bad (worn, weak broken, or sticking)

Piston ring/land clearance excessive

Cylinder head gasket damaged

Cylinder head warped

Valve spring broken or weak

Valve not seating properly (valve bent, worn, or carbon accumulation on the seating surface)

Poor Running at Low Speed:

Spark weak:

Battery voltage low

Spark plug dirty, broken, or maladjusted

Spark plug cap or high tension wiring trouble

Spark Plug cap shorted or not in good contact

Spark plug incorrect

IC igniter trouble

Pickup coil trouble

Ignition coil trouble

Fuel/air mixture incorrect:

Pilot screw maladjusted

Pilot jet, or air passage clogged

Air bleed pipe bleed holes clogged

Pilot passage clogged

Air cleaner clogged, poorly sealed, or missing

Starter plunger stuck open

Fuel level in carburetor float bowl too high or too low

Fuel tank air vent obstructed

Carburetor holder loose

Air cleaner duct loose

Compression low:

Spark plug loose

Cylinder head not sufficiently tightened down

No valve clearance

Cylinder, piston worn

Piston ring bad (worn, weak, broken, or sticking)

Piston ring/land clearance excessive

Cylinder head warped

Cylinder head gasket damaged

Valve spring broken or weak

Valve not seating properly (valve bent, worn, or carbon accumulation on the seating surface)

Other:

IC igniter trouble

Carburetors not synchronizing

Vacuum piston doesn’t slide smoothly

Engine oil viscosity too high

Drive train trouble

Brake dragging

Poor Running or No Power at High Speed:

Firing incorrect:

Spark plug dirty, broken, or maladjusted

Spark plug cap shorted or not in good contact

Spark plug incorrect

IC igniter trouble

Pickup coil trouble

Ignition coil trouble

Fuel/air mixture incorrect:

Starter plunger stuck open

Main jet clogged or wrong size

Jet needle or needle jet worn

Air jet clogged

Fuel level in carburetor float bowl too high or too low

Bleed holes of air bleed pipe or needle jet clogged

Air cleaner clogged, poorly sealed, or missing

Air cleaner duct poorly sealed

Water of foreign matter in fuel

Carburetor holder loose

Fuel tank air vent obstructed

Fuel tap clogged

Fuel line clogged

Compression low:

Spark plug loose

Cylinder head not.sufficiently tightened down

No valve clearance

Cylinder, piston worn

Piston ring bad (worn, weak, broken, or sticking)

Piston ring/land clearance excessive

Cylinder head gasket damaged

Cylinder head warped

Valve spring broken or weak

Valve not seating properly (valve bent, worn, or carbon accumulation on the seating surface.)

Knocking:

Carbon built up in combustion chamber

Fuel poor quality or incorrect

Spark plug incorrect

IC igniter trouble

Miscellaneous:

Throttle valve won’t fully open

Vacuum piston doesn’t slide smoothly

Brake dragging

Clutch slipping

Overheating

Engine oil level too high

Engine oil viscosity too high

Drive train trouble

Overheating:

Firing incorrect:

Spark plug dirty, broken, or maladjusted

Spark plug incorrect

IC igniter trouble

Fuel/air mixture incorrect:

Main jet clogged or wrong size

Fuel level in carburetor float bowl too low

Carburetor holder loose

Air cleaner poorly sealed, or missing

Air cleaner duct poorly sealed

Air cleaner clogged

Compression high:

Carbon built up in combustion chamber

Engine load faulty:

Clutch slipping

Engine oiHevel too high

Engine oil viscosity too high

Drive train trouble

Brake dragging

Lubrication inadequate:

Engine oil level too low

Engine oil poor quality or incorrect

Coolant incorrect:

Coolant level too low

Coolant deteriorated

Cooling system component incorrect:

Radiator clogged

Thermostat trouble

Radiator cap trouble

Thermostatic fan switch trouble

Fan relay trouble

Fan motor broken

Fan blade damaged

Water pump not turning

Water pump impeller damaged

Over Cooling:

Cooling system component incorrect:

Thermostatic fan switch trouble

Thermostat trouble

Clutch Operation Faulty:

Clutch slipping:

Friction plate worn or warped

Steel plate worn or warped

Clutch spring broken or weak

Clutch release mechanism trouble

Clutch hub or housing unevenly worn

Clutch not disengaging properly:

Clutch plate warped or too rough

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 trouble

Gear Shifting Faulty:

Doesn’t go into gear; shift pedal doesn’t return:

Clutch not disengaging

Shift fork bent or seized

Gear stuck on the shaft

Shift return spring weak or broken

Shift return spring pin loose

Pawl spring broken

Shift mechanism arm broken

Jumps out of gear:

Shift fork worn

Gear groove worn

Gear dogs and/or dog holes worn

Shift drum groove worn

Neutral positioning pin spring weak or broken

Shift fork pin worn

Drive shaft, output shaft, and/or gear splines worn

Overshifts:

Neutral positioning pin spring weak or broken

Pawl spring broken

Abnormal Engine Noise:

Knocking:

IC igniter trouble

Carbon built up in combustion chamber

Fuel poor quality or incorrect

Spark plug incorrect

Overheating Piston slap:

Cylinder/piston clearance excessive

Cylinder, piston worn

Connecting rod bent

Piston pin, piston holes worn

Valve noise:

Valve clearance incorrect

Valve spring broken or weak

Camshaft bearing worn

Other noise:

Connecting rod small end clearance excessive

Connecting rod big end clearance excessive

Piston ring worn, broken or stuck

Piston seizure, damage

Cylinder head gasket leaking

Exhaust pipe leaking at cylinder head connection

Cran kshaft runout excessive

Engine mounts loose

Crankshaft bearing worn

Camshaft chain tensioner trouble

Camshaft chain, sprocket, guide worn

Abnormal Drive Train Noise:

Clutch noise:

Weak or damaged damper

Clutch housing/friction plate clearance excessive

Clutch housing gear worn

Transmission noise:

Bearings worn

Transmission gears worn or chipped

Metal chips jammed in gear teeth

Engine oil insufficient

Drive chain noise:

Drive chain adjusted improperly

Chain worn

Rear and/or engine sprocket worn

Chain lubrication insufficient

Rear wheel misaligned

Abnormal Frame Noise:

Front fork noise:

Oil insufficient or too thin

Spring weak or broken

Rear shock absorber noise:

Shock absorber damaged

Disc brake noise:

Pad installed incorrectly

Pad surface glazed

Disc warped

Caliper trouble

Other noise:

Bracket, nut, bolt, etc. not properly mounted or

tightened

Oil Pressure Warning Light Goes On:

Engine oil pump damaged

Engine oil screen clogged

Engine oil level too low

Engine oil viscosity too low

Camshaft bearings worn

Crankshaft bearings worn

Oil pressure switch damaged

Wiring damaged

Relief valve stuck open

O-ring at the oil pipe in the crankcase damaged

Exhaust Smokes Excessively:

White smoke:

Piston oil ring worn

Cylinder worn

Valve oil seal damaged

Valve guide worn

Engine oil level too high

Black smoke:

Air cleaner clogged

Main jet too large or fallen off

Starter plunger stuck open

Fuel level in carburetor float bowl too high

Brown smoke:

Main jet too small

Fuel level in carburetor float bowl too low

Air cleaner duct loose

Air cleaner poorly sealed or missing

Handling and/or Stability Unsatisfactory:

Handlebar hard to turn:

Steering stem locknut too tight

Bearing damaged

Steering bearing lubrication inadequate

Steering stem bent

Tire air pressure too low

Handlebar shakes or excessively vibrates:

Tire worn

Swing arm pivot bearing worn

Rim warped, or not balanced

Wheel bearing worn

Handlebar mounting bolts loose

Steering stem head bolt loose

Handlebar pulls to one side:

Frame bent

Wheel misalignment

Swing arm bent or twisted

Steering maladjusted

Front fork bent

Right/left fork legs oil level unbalanced

Shock absorption unsatisfactory:

(Too hard)

Front fork oil excessive

Front fork oil viscosity too high

Tire air pressure too high

Front fork bent

(Too soft)

Front fork oil insufficient and/or leaking

Front fork oil viscosity too low

Front fork, rear shock absorber spring weak

Rear shock absorber oil leaking

Brake Doesn’t Hold:

Air in the brake line

Pad or disc worn

Brake fluid leak

Disc warped

Contaminated pad

Brake fluid deteriorated

Primary or secondary cup damaged

Master cylinder scratched inside

Battery Discharged:

Battery faulty (e.g., plates sulphated, shorted through sedimentation, electrolyte level too low)

Battery leads making poor contact

Load excessive (e.g., bulb of excessive wattage)

Ignition switch trouble

Alternator trouble

Wiring faulty

Regulator/Rectifier trouble

Battery Overcharged:

Regulator/Rectifier trouble
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Maybe PB forum can dedicate sitespace for a HTML version with index.But workable as is :)

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