Suzuki DL650K5 Service Manual page 411

ENGINE RUNS POORLY IN HIGH SPEED RANGE
Symptom, possible causes and remedy
1) Defective engine internal/electrical parts
• Weakened valve springs.
• Worn camshafts.
• Valve timing out of adjustment.
• Too narrow spark plug gaps.
• Ignition not advanced sufficiently due to poorly
working timing advance circuit.
• Defective ignition coils.
• Defective CKP sensor.
• Defective ECM.
• Clogged fuel hose, resulting in inadequate fuel
supply to injector.
• Defective fuel pump.
• Defective TP sensor.
• Defective STP sensor or STVA.
• Clogged air cleaner element.
2) Defective air flow system
• Clogged air cleaner element.
• Defective throttle valve.
• Defective secondary throttle valve.
• Sucking air from throttle body joint.
• Defective ECM.
• Imbalanced throttle valve synchronization.
3) Defective control circuit or sensor
• Low fuel pressure.
• Defective TP sensor.
• Defective IAT sensor.
• Defective CKP sensor.
• Defective GP switch.
• Defective IAP sensor.
• Defective ECM.
• TP sensor out of adjustment.
• Defective STP sensor and/or STVA.
Replace.
Replace.
Adjust.
Adjust.
Replace ECM.
Replace.
Replace.
Replace.
Clean and prime.
Replace.
Replace.
Replace.
Clean or replace.
Clean or replace.
Adjust or replace.
Adjust or replace.
Repair or replace.
Replace.
Adjust.
Repair or replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Replace.
Adjust.
Replace.
SERVICING INFORMATION 9-7