DAELIM VJF125 Service Manual - Engine Lacks Power

21-2

TROUBLESHOOTING

ENGINE LACKS POWER

Pressure normal

Pressure low

Punctured tire.

Faulty tire valve.

1. Check tire pressure.

Wheel rotate freely.

Wheel don’t rotate

freely

Dragged brake.

Worn or damaged wheel bearings.

Lacked wheel bearings lubrication.

D

Axle nut tightened excessively.

2. Raise wheels off ground and

rotate by hands.

Engine speed increased.

Engine speed not

changed.

Clutch slipping.

Worn clutch disk and plate.

Damaged clutch disk and plate.

3. Accelerate suddenly.

Engine speed increased.

Engine speed

doesn’t increase.

Closed carburetor choke.

Clogged fuel aisle.

Clogged air cleaner.

Clogged fuel tank breather.

Clogged muffler.

4. Accelerate lightly.

Correct

Incorrect

Faulty ECU unit.

Faulty pulse generator.

5. Check ignition timing by

using scan.

Correct

Incorrect

Improper valve adjustment.

Worn valve seat.

6. Check valve clearance

Compression normal

Low

Improper valve operation.

Worn cylinder and piston ring.

Worn cylinder head gasket.

Incorrect valve timing.

7. Measure the cylinder

compression.

Not clogged

Clogged

Damaged fuel strainer or screen.

Poor carburetor maintenance.

8. Check the carburetor for

clogging.

INSPECTION

CAUSE OF TROUBLE