Honda Metropolitan CHF50 Service Manual page 315

TROUBLESHOOTING
7. Ignition Timing Inspection
Check the ignition timing.
Is the ignition timing within specification?
NO - • Faulty ECM
• Faulty ignition pulse generator
• Improper valve timing
YES - GO TO STEP 8.
8. Cylinder compression Inspection
Test the cylinder compression.
Is the compression within specification?
NO - • Valve clearance too small
• Worn cylinder and piston rings
• Improper valve timing
• Damaged cylinder head gasket
YES - GO TO STEP 9.
9. Carburetor Inspection
Check the carburetor for clogs.
Is the carburetor clogged?
YES - Carburetor not serviced frequently enough
NO - G O TO STEP 10.
10. lubrication Inspection
Remove the cylinder head cover and inspect for sings of proper lubrication.
Is the valve train lubricated properly?
NO - Clogged oil passage
YES - G O TO STEP 11.
11. Overheating Inspection
Check for engine overheating.
Is the engine overheating?
YES - Coolant level too low
Faulty radiator fan
Thermostat stuck closed
Excessive carbon build-up in combustion chamber
Use of poor quality fuel
Clutch slipping
Lean fuel mixture
NO - G O TO STEP 12.
12. Engine Knocking Inspection
Accelerate or run at high speed.
te the engine knocking?
YES - • Worn piston and cylinder
Wrong type of fuel
Excessive carbon build-up in combustion chamber
Ignition timing too advanced (faulty ECM)
Lean fuel mixture
NO - • Engine does not knock
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