Vento Phantom R4i - Trouble Shooting; Engine Troubleshooting

VENTO MOTORCYCLES
Rev no.01/ page 80of 84
CHAPTER 7
TROUBLE SHOOTING
ENGINE
Complaint Symptom and possible causes Remedy
Engine does not start, or
is hard to start.
Compression too low
1. Excessively worn cylinder or piston & piston rings.
2. Sticky piston rings in groove.
3. Compression leaks from the joint in crankcase,
cylinder or cylinder head.
4. Damaged or leaks of valve.
5. Spark plug too loose or poor seating.
6. Worn-out cylinder bore.
7. Too slowly starter cranking starter motor
Plug not sparking
1. Damaged spark plug or suppressor cap.
2. Dirty or fouled spark plug.
3. Defective CDI & ignition coil unit or stator coil.
4. Open or short in high-tension cord.
5.
Defective ignition switch.
No fuel reaching to the carburetor
1. Clogged hole in the fuel tank cap.
2. Clogged or defective fuel cock.
3. Defective carburetor float valve.
4. Clogged fuel hose or defective vacuum hose.
Replace.
Repair or replace.
Repair or replace.
Repair or replace.
Retighten
Replace or rebore.
See electrical
section.
Replace.
Replace.
Clean.
Replace.
Replace.
Replace
Clean or replace.
Clean or replace.
Replace.
Clean or replace.
Engine not starts easily. 1. Carbon deposited on the spark plug.
2. Defective CDI & ignition coil unit.
3. Clogged fuel hose.
4. Clogged jets in carburetor.
5. Clogged exhaust pipe.
Clean.
Replace.
Clean.
Clean.
Clean.
Noisy engine.
Noise appears to come from piston
1. Piston or cylinder worn-out.
2. Combustion chamber fouled with carbon.
3. Piston pin, bearing or piston pin bore worn.
Replace.
Clean.
Replace.