DAELIM Daystar VL125E Service Manual page 251

Engine Lacks Power
1. Raise wheels off ground
and spin by hands.
Wheels spin freely. Wheels spin freely.
2. Check tire pressure.
Pressure normal.
3. Check clutch slipping.
Engine speed increased.
4. Accelerate lightly.
Engine speed increased.
5. Check ignition timing.
Correct.
6. Test cylinder compression.
Normal.
7. Check valve clearance.
Correct.
8. Check fule pump fuel tube, injector
Not clogged.
9. Check spark plug.
Not fouled or discolored.
Wheel don't
spin freely.
Pressure low.
Engine speed not
changed when
Clutch is released
Engine speed
doesn't increase.
Incorrect.
Too low.
Incorrect.
Clogged.
Fouled
or discolored.
Troubleshooting
Brake dragging
Worn or damaged wheel bearings
Wheel bearings need lubrication
Punctured tire
Faulty tire valve
Faulty clutch spring.
Worn clutch disk/plate
Wraped clutch disk/plate
Carburetor choke closed
Clogged air cleaner
Clogged jets
Clogged fuel tank breather
Clogged muffler
Faulty ECU
Faulty crank position sensor.
Flywheel is not installed properly
Worn cylinder and piston rings
Leaking head gasket
Improper valve timing
Faulty valve seat
Improper valve adjustment
Worn valve seat
Clean
Clean
Spark plug of incorrect heat range
22-2