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