Moped Riders Association

[crankorange80]

Hi. I have been running on a daily basis for a year a 1980 suzuki fz50 two stroke 49cc moped/scooter. Ive also had a few scary moments happen when ive beed running full throttle flat out for more than ten minutes on the open road.

When riding at full throttle 30mph i have experienced the rear wheel lock up on me just as if i had engaged the rear brake fully on. I think there is an oil starvation problem happening here. the enging is fine running around town stopping at starting but once i ride at full speed for more than ten mins the engine seems to suffer a partial seizure.

I think the pistion slightly over heats and is suffering a partial seizure. while having the piston lock up at full revs and the auto clutch engaged makes the rear wheel lock up. The odd thing is after a lockup, i kick start the engine it will run and the engine seems to struggle to tick over or rev but if I leave it ticking over for just two minutes it ticks over and runs normally at tick over and rev as is nothing happened untill i try run at full speed again for more than ten mins.

I cleaned the carb and jets. replaced the old gearbox oil for good knew stuff and bought a knew air filter and spark plug. in its bike manual is tells me to have the air bleed screw opened anti clockwise by 1 and a half turns out but im still experiencing seizures at full speed. I have know set the air bleed screw to just one turn out instead of one and a half turns out to give a richer mixture to see how things go.

Has anyone reading this heard this type of problem yourself? Have you any suggestion to what the cause of this problem may be. would cheap two stroke oil cause these symptons? I have been using a cheaper two stroke oil and im thinking this could be adding to the problem.


Thanks for your replies in advance.

[John]

!st use a synthetic and then start by increasing your jet. Trial and error.