HYOSUNG GT 650, Service Manual

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SERVICING INFORMATION 8-4
CARBURETOR
Complaint Symptom and possible causes Remedy
Trouble with
starting. 1. Starter jet is clogged.
2. Starter pipe is clogged.
3. Air leaking from a joint between starter body and carburetor.
4. Starter plunger is not operating properly.
Clean.
Clean.
Check starter body and
carburetor for tightness,
adjust and replace gasket.
Check and adjust.
Medium or high
speed trouble. 1. Main jet or main air jet is clogged.
2. Needle jet is clogged.
3. Throttle valve is not operating properly.
4. Filter is clogged.
Check and clean.
Check and clean.
Check throttle valve for
operation.
Check and clean.
Idling or low-speed
trouble. 1. Pilot jet, pilot air jet are clogged or loose.
2. Pilot outlet or bypass is clogged.
3. Starter plunger is not fully closed. Check and clean.
Check and clean.
Check and clean.
Overflow and fuel
level fluctuations. 1. Needle valve is worn or damaged.
2. Spring in needle valve is borken.
3. Float is not working properly.
4. Foreign matter has adhered to needle valve.
5. Fuel level is too high or low. Replace.
Replace.
Check and adjust.
Clean.
Adjust float height.
RADIATOR (COOLING SYSTEM)
Complaint Symptom and possible causes Remedy
Engine overheats. 1. Not enough engine coolant.
2. Radiator core clogged with dirt or scale.
3. Faulty cooling fan.
4. Defective cooling fan thermo-switch.
5. Clogged water passage.
6. Air trapped in the cooling circuit.
7. Defective water pump.
8. Use of incorrect engine coolant.
9. Defective thermostat. Add coolant.
Clean.
Repair or replace.
Replace.
Clean.
Bleed out air.
Replace.
Replace.
Replace.
Engine overcools. 1. Defective cooling fan thermo-switch.
2. Extremely cold weather.
3. Defective thermostat. Replace.
Put on the radiator cover.
Replace.