Troubleshooting

ENGINE DOES NOT START OR IS HARD TO START

ENGINE LACKS POWER

POOR PERFORMANCE AT LOW AND IDLE SPEED

22 3

POOR PERFORMANCE AT HIGH SPEED

POOR HANDLING

ENGINE DOES NOT START OR IS HARD TO START

1. Check for operation of the fuel pump

Normal

Abnormal

Possible cause

2. Inspect the fuel flow

Normal

Ahnormal

• Faulty pressure regulator (Section 5)

3. Inspect the fuel injector

Normal

Abnormal

4. Perform a spark test Good spark

Weak or no spark

5. Test cylinder compression

Compression normal

6. Starting following normal procedure Engine does not start

7. Remove and inspect spark plug

I ow compression

Engine starts hut stops

Wet plug

• Faulty spark plug

• Fouled spark plug

• Broken or shorted spark plug wire

• Faulty ignition switch

• Faulty ignition pulse generator

• Faulty engine stop switch

• Loose or disconnected ignition system wires

• Valve stuck open

• Worn cylinder and piston ring

• Damaged cylinder head gasket

• Improper valve timing

• Improper starter valve operation

• Intake pipe leaking

• Improper ignition timing (faulty ignition coil or ignition pulse generator)

• Fuel contaminated

• Starter valve closed

• Throttle valve open

• Clogged air cleaner

ENGINE LACKS POWER

1. Raise wheel off the ground and spin by hand

Wheel spins freely

Wheel does not spin-freely

Possible cause

• • Broke dragging • Worn or damaged wheel bearing

?. Check tire pressure

Pressure normal

Pressure low

Faulty tire valve Punctured tire

3. Accelerate rapidly from low to second -

Engine speed reduced when clutch is released

4. Accclerate lightly

Engine speed increase 5. Check ignition timing -

Correct

6. Test cylinder compression

Normal

7. Inspect fuel flow Normal

Engine speed doe not change accordingly when clutch is released

Engine speed does not increase

Incorrect

Incorrect

Abnormal

• Clutch slipping

• Worn clutch discs/plates

• Warped clutch discs/plates

• Weak clutch spring

• Additive in engine oil

• Air clcaner dirty

• Restricted fuel flow

• Clogged muffler

• Pinched fuel tank breather

• Faulty ignition pulse generator

Valve stuck open Worn cylinder and piston rings Leaking head gasket Improper valve timing

Faulty pressure regulator (Section 5)

8. Inspect the fuel injector

Normal

Abnormal

See section 5

9. Remove spark plugs

Fouled or discolored

Faulty spark plug

Not fouled or discolored

10. Cheek oil level and condition

Correct

Incorrect

• Contaminated oil

11. Remove cylinder head cover and inspcct lubrication i

Valve train lubricated properly t

Valve train not lubricated properly

Cluyyed oil passage Clogged oil control orifice

Possible cause

11. Check for engine overheating

Not overheating

Overheating

12. Accelerate or run at high speed i

Engine does nut knock

Engine knocke

■ Coolant level low

• Fan motor not working (faulty fan motor switch)

• Thermostat stuck close

• Excessive carbon build-up in combustion chamher

• Use of poor quality fuel

• Clutch slipping

Worn piston and cylinder Wrong type of fuel Excessive carbon build-up in com bustion chamber

Ignition timing to advanced (faulty ECM)

Lean fuel mixture

POOR PERFORMANCE AT LOW AND IDLE SPEED

1. Check ignition timing t

Correct

Incorrect

Possible cause

2. Check the starter valve synchronization i

Correct

Incorrect

3. Inspect the fuel flow i

Normal

Abnormal

Faulty pressure regulator (Section b)

4. Inspect the fuel injector Normal

Abnormal

Sec section 5

5. Check for leaks in the intake pipe

Not leak

Leakinq

Loose insulator clamp Damaged insulator

6. Perform spark test

Good spark

Weak or intermittent spark

• Faulty spark plug

• Faulty carbon or wet fouled spark plug

• Faulty ignition coil

• Faulty engine stop switch

• Faulty ignition pulse generator

• Faulty ignition switch

• Loose or disconnected ignition system wires

POOR PERFORMANCE AT HIGH SPEED

1. Cheek ignition timing i

Correct i

2. Inspect the fuel flow

Normal

Incorrect

Abnormal

Possible cause

• Faulty pressure regulator (Section 5)

3. Inspect the fuel injector

Normal

Abnormal

See section 5

4. Check valve timing

Correct

Incorrect

• Camshaft not installed properly

5. Check valve spring -

Not weak

POOR HANDLING

Weak

Faulty valve spring

1. Steering is heavy

2. Wheel wobbles

3. Motorcycle pulls to one side

Possihle cause

- • Steering stem adjusting nut too tight

• Damaged steering head bearings

• Improper installed wheel hub

• Swingorm pivot bearing excessively worn

• Front and rear wheel not aligned

• Bent swingarm

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