ENGINE DOES NOT START OR IS HARD TO START
STEP 1. Ensure that all switches are in the ON position
STEP 2. Check for fuel flow to the carburetor.
If carburetor has primer or choke, activate same. If fuel does not flow: remove fuel line from carburetor, open fuel valve and watch for fuel flow. If fuel flows, proceed to STEP 3. If fuel still does not flow: check fuel level in tank, if OK, clean tank and fuel filters. Attempt to start moped, if moped does not start, proceed to STEP 3.
STEP 3. Be sure there is no fuel leakage prior to this making this test!
Check for adequate spark.
Remove spark plug from cylinder head, ground outer shell to engine and crank engine. Observe the spark, a crisp blue color is normal, orange color denotes ignition malfunction. If a strong blue spark is evident, proceed to STEP 4. If weak or no spark: replace spark plug with a known good spark plug and retest. Still weak or no spark: unscrew plug protector from the high tension wire and hold wire 1/2 inch from engine and crank engine. If spark occurs, replace spark plug protector and proceed to STEP 4. If no spark, check the ignition points to make sure they are opening and closing. If they are but points are blue or burned, replace points and condensor. If spark then occurs, attempt to start engine. If spark does not occur: check magneto by cranking engine with headlamp on, if headlamp lights, magneto is funtional. If not, replace magneto and attempt to start. If spark still does not occur, replace ignition coil and attempt to start.
STEP 4. The following conditions now apply: fuel flows to carburetor, spark occurs, but the moped will not start.
Check and adjust starter clutch adjustment. Check engine compression, 2 cycle engines need at least 75 Lbs per sq in of compression to run. If not so, you to check for carbon buildup in port or exhaust or you need rings and/or piston service.
STEP 5. Following conditions now apply: fuel flows, spark occurs and you have sufficient compression.
Attempt to start engine. If it doesn't start, check spark plug for the following conditions: if wet, recheck fuel quality for staleness or contamination. Possible causes are: excess oil mixture, clogged air filter, or main jet too big or loose in carburetor. If plug is dry: clogged main jet, stuck needle or float, or clogged filter in carburetor.
Having corrected any deficiencies in these areas the bike should now run!
OTHER COMMON COMPLAINTS
LACK OF POWER OR TOP SPEED
Check for dragging brakes, tight chain, under inflated tires, defective spark plug, cloged air filter, clogged exhaust or port, choke not returning to fully open, low float level, incorrect or drilled out main jet, or incorrect ignition timing.
EXCESSIVE SMOKING
Wrong gas/oil mixture or defective crankcase seals.
ENGINE RACING OR NO IDLE
Check for loose carburetor or manifold, defective crankcase seals, or incorrect carburetor adjustments.