Honda SH300 2006 Manual page 504

ENGINE LACKS POWER
1. Engine Oil Inspection
Check the oil level and condition.
Is the oil level correct and the oil in good condition?
YES
NO
2. Wheel Inspection
Raise the rear wheel off the ground and spin it by hand.
Does the wheel spin freely?
YES
NO
3. Tire Pressure Inspection
Check the tire pressure.
Is the tire pressure correct?
YES
NO
4. Spark Plug Inspection
Remove and inspect the spark plug.
Is spark plug in good condition?
YES
NO
5. Ignition Timing Inspection
Check the ignition timing.
Is the ignition timing correct?
YES
NO
6. Cylinder compression Inspection
Test the cylinder compression.
Is the compression within specification?
YES
NO
– GO TO STEP 2.
– • Oil level too high
• Oil level too low
• Contaminated oil
– GO TO STEP 3.
– • Brake dragging
• Worn or damaged final reduction and driven pulley bearings
• Bent final gear shaft
– GO TO STEP 4.
– • Faulty tire valve
• Punctured tire
– GO TO STEP 5.
– • Plug not serviced frequently enough
• Incorrect spark plug heat range
• Incorrect spark plug gap
• Dirty air cleaner element
– GO TO STEP 6.
– • Faulty ECM
• Faulty CKP sensor
• Improper valve timing
– GO TO STEP 7.
– • Valve stuck open
• Worn cylinder and piston rings
• Damaged cylinder head gasket
• Seized valve
• Incorrect valve seat contact
• Improper valve timing
TROUBLESHOOTING
25-3