Poor Performance At High Speed - Honda Metropolitan CHF50 Service Manual

TROUBLESHOOTING
POOR PERFORMANCE AT HIGH SPEED
1. 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 2.
2. Fuel Line Inspection
Disconnect the fuel hose at the carburetor.
Does the fuel flow freely?
NO - • Clogged fuel line
Clogged fuel cap breather
Clogged fuel filter
Faulty fuel pump
Loose or disconnected fuel pump system line
YES - GO TO STEP 3.
3. Carburetor Inspection
Remove the carburetor and check for clogged jets.
Are the jets clogged?
YES - Clean the jets
NO - GO TO STEP 4.
4. Spark Plug Inspection
Remove and inspect the spark plug.
Is the spark plug in good condition?
NO - • Plug not serviced frequently enough
Incorrect spark plug heat range
Incorrect spark plug gap
Faulty starting enrichment (SE) valve
Air cleaner dirty
YES - GO TO STEP 5.
5. Valve Timing Inspection
Check the valve timing.
Is the valve timing correct?
NO - Cam sprocket not installed properly
YES - GO TO STEP 6.
6. Valve Spring Inspection
Check the valve springs.
Is the valve spring free length within specification?
NO - Faulty valve spring
YES - GO TO STEP 7.
7. Camshaft Inspection
Remove and inspect the camshaft.
Is the cam lobe height within specification?
NO - Faulty camshaft
YES - Camshaft is OK
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