Check the spark plug gap, replace a fouled plug, or inspect the CDI module, ignition coil, and stator wiring.
The ignition system operates independently of the battery via an AC-CDI system. The battery is only required for the electric starter and lighting. Component Checks
JASO MA/MA2 certified 10W-40 4-stroke motorcycle oil (do not use automotive oil with friction modifiers, as it will cause the wet clutch to slip). 152fmh engine service manual
Check the level; do not screw the dipstick in when checking. Valve Clearance Adjustment
[Stator / Magneto] ---> [CDI Box] ---> [Ignition Coil] ---> [Spark Plug] ^ ^ | | [Kill Switch / Key] ----------+ No Spark Diagnostic Flowchart Check the spark plug gap, replace a fouled
AC Charging Output (Feeds into the regulator/rectifier for battery charging). Ignition Circuit Diagnosis
Remove the timing hole caps on the left crankcase cover. Rotate the flywheel until the "T" mark aligns with the notch. Specs: Intake: 0.05mm (0.002 in) Exhaust: 0.05mm (0.002 in) Ignition Circuit Diagnosis Remove the timing hole caps
Drain the engine oil and remove the exhaust pipe and carburetor.
Ensure the "IN" mark stamped on the piston face points upward toward the intake valve.
Start the engine and let it warm up. Turn the idle speed screw (with the external spring) until the engine idles smoothly without stalling or spinning the rear wheel. Oil Change and Screen Cleaning
If the clearance is incorrect, loosen the locknut with a 9mm wrench. Turn the square adjuster screw until the feeler gauge fits perfectly. Hold the adjuster screw firmly in place and torque down the locknut.