Honda SH125 Manual page 355

TROUBLESHOOTING
7. Ignition Timing Inspection
Check the ignition timing.
Is the ignition timing correct?
NO
-
Faulty
ECM
Faulty crankshaft position (CKP) sensor
Improper valve timing
YES -
GO TO STEP
8.
8. Cylinder compression Inspection
Test the cylinder compression.
Is the compression within specification?
NO
-
Valvestuckopen
Worn cylinder and piston rings
Seized valve
Incorrect valve seat contact
Improper valve timing
YES
-
GO TO STEP 9.
9. Fuel Injection System Inspection
Check the fuel injection system (page 5-7).
Is the fuel injection system normal?
NO
-
Faulty fuel injection system.
YES
-
GO 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
-
GO 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
-
GO TO STEP 12.
12.
Engine Knocking Inspection
Accelerate or run
a t
high speed.
Is 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
-
Engine does not knock
NO
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