Suzuki TU250X Service Manual page 326

10-6 SERVICING INFORMATION
Complaint
Engine lacks power. Defective engine internal/electrical parts
Symptom and possible causes
1. Loss of valve clearance
2. Weakened valve springs
3. Valve timing out of adjustment
4. Worn piston rings or cylinder
5. Poor seating of valves
6. Fouled spark plug
7. Incorrect spark plug
8. Clogged fuel injector
9. TP sensor out of adjustment
10. Clogged air cleaner element
11. Sucking air from throttle body joint
12. Too much engine oil
13. Defective fuel pump or ECM
14. Defective CKP sensor or ignition coil
15. Defective STP sensor or STVA
Defective control circuit or sensor
1. Low fuel pressure
2. Defective TP sensor
3. Defective IAT sensor
4. Defective CKP sensor
5. Defective IAP sensor
6. Defective ECM
7. TP sensor out of adjustment
8. Defective STP sensor and/or STVA
Remedy
Adjust.
Replace.
Adjust.
Replace.
Repair.
Clean or replace.
Adjust or replace.
Replace.
Adjust.
Replace.
Retighten or replace.
Drain out excess oil.
Replace.
Replace.
Replace.
Repair or replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Adjust.
Replace.