Suzuki RM-z450 Owner's Service Manual page 58

3-6 TROUBLESHOOTING
Complaint
Engine lacks power. Defective engine internal/electrical parts
Engine overheats
Symptom and possible causes
• Loss of valve clearance
• Weakened valve springs
• Valve timing out of adjustment
• Worn piston ring or cylinder
• Poor seating of valves
• Fouled spark plug
• Incorrect spark plug
• Clogged fuel injector
• Clogged air cleaner element
• Sucking air from throttle body joint or intake pipe
• Too much engine oil
• Defective fuel pump or ECM
• Defective CKP sensor or ignition coil
Defective control circuit or sensor
• Low fuel pressure
• Defective TP sensor
• Defective CKP sensor
• Defective IAP sensor
• Defective IAT sensor
• Defective ECM
• Defective GP switch
Defective engine internal parts
• Heavy carbon deposit on piston crown
• Not enough oil in the engine
• Defective oil pump or clogged oil circuit
• Sucking air from throttle body joint or intake pipe
• Use incorrect engine oil
• Defective cooling system
Lean fuel/air mixture
• Short-circuited IAP sensor/lead wire
• Short-circuited IAT sensor/lead wire
• Sucking air from throttle body joint or intake pipe
• Defective fuel injector
• Defective ECT sensor
Other factors
• Ignition timing is too advanced due to defective tim-
ing advance system (ECT sensor, GP switch, CKP
sensor and ECM)
• Drive chain is too tight
Remedy
Adjust
Replace
Adjust
Replace
Repair
Clean or replace
Adjust or replace
Replace
Clean or replace
Retighten or replace
Drain out excess oil
Replace
Replace
Replace
Replace
Replace
Replace
Replace
Replace
Replace
Clean
Add oil
Replace or clean
Retighten or replace
Change
See cooling section
Repair or replace
Repair or replace
Retighten or replace
Replace
Replace
Replace
Adjust