Vento Phantom R4i, Service Maintenance Manual

Page: 83 / 88

VENTO MOTORCYCLES
Rev no.01/ page 83of 84
7. Use of incorrect spark plug.
8. Clogged exhaust pipe/muffler.
9. Clogged air intake with dust
oil
Change & use specified.
Clean or replace.
Clean
CARBURETOR
Complaint Symptom and possible causes Remedy
Trouble with
starting.
1. Starter jet is clogged.
2. Air leaking from a joint between starter body and
carburetor.
3. Air leaking from carburetor′s joint or vacuum hose joint.
4. Starter plunger is not operating properly.
5. Clogged fuel pipe
6. Clogged enrichner (choke) or air cleaner
Clean.
Check starter body and
carburetor for tightness,
and replace gasket.
Check and replace.
Check and replace.
Clean.
Check and clean.
Idling or low-
speed
troubles.
1. Pilot jet, pilot air jet are clogged or loose.
2. Air leaking from carburetor′s joint, vacuum pipe joint, or
starter.
3. Pilot outlet is clogged.
4. Starter plunger is not fully close.
Check and clean.
Check and replace.
Check and clean.
Check and replace.
Complaint Symptom and possible causes Remedy
Medium- or
high-speed
trouble.
1. Main jet or main air jet is clogged.
2. Needle jet is clogged.
3. Fuel level is improperly set.
4. Throttle valve is not operating
properly.
7. Fuel filter is clogged.
8. Defective fuel tap
Check and clean.
Check and clean.
Check and replace.
Check throttle valve for operation.
Check and clean.
Replace.
Overflow and
fuel level
fluctuations. 1. Needle valve is worn or damaged.
2. Spring in needle valve is broken.
3. Float is not working properly.
4. Foreign material has adhered to
needle valve.
5. Fuel level is too high or low.
Replace.
Replace.
Check and adjust.
Clean.
Adjust float height.