Hello,
I have QMB139 engine scooter.
I have big problems for ca 2 years with my scooter and practical almost was changed (spare part).
I tried / changed:
New spark plug, new electrical choke, new ignition coil, new fuel filter, new tubes for fuel way, new vacuum valve.Ride without air filter, clean carburettor, new main jets (80 original, 82), set float level, set richness mixtureValve adjustment engine OKNew piston kit (Naraku), I have bent exhaust valve and it was changed in head engine.New variator Naraku and new clutch spring, belt is OK.I got 800$ to all repair per 2 years and my scooter is bad again.
My scooter had bad compression engine and after repair new exhaust valve and piston kit, it runs good ca 4000km.
Motor and gear oil I have full.
But now my scooter again has problems and I don't know what have to make with it. My head is full bad from this I can't sleep.
Problem: As cold scooter runs good,
if I drive ca 10km in a row scooter stop go like I deckchair fuel tube (or no fuel). I have transparent fuel tube and from tank fuel flows good if problem occur. I add gas and scooter has very bad reaction often dies engine or does'nt go good to Revolution. If engine dies, ca 10 minutes after he goes start and go next good, often I can't ca 10 minutes start engine.
I tried to get a lot of fuel from other tank stations.
My spark plug is here on picture: