NO START!!

Matthew Ciniello /

So after some investigation i've found out that my Piaggio P501 uses a rotary valve instead of a reed valve. I took off the head today and cleaned off some of the carbon buildup. I'm positive it is getting a strong spark. It hasn't been run in 17 years. and i'm not sure of the compression, there is lots of resistance when turning the engine by hand, but when let in TDC the resistance fades away. The car turns over, and is getting fuel, but will not start and back fires though the carb often. When trying to start, the engine will ocasionally burp, and the rythmic starting noise will pause for a while and usually back fires afterwards. I'm not very firmillar with 2 strokes but perhaps it need new piston rings? any insight?

Best Regards,

Matt

Re: NO START!!

anything's possible.. the rings or the cylinder may be in bad shape.. you might even have a hole in the piston.. who knows..

All it takes is 3 things.. spark, compression and fuel. Backfires can usually be traced to problems with intake timing.

If it were my bike i would just continue to investigate and solve the mystery by a process of elimination.

A good tutorial on how 2-strokes operate can be found at http://science.howstuffworks.com/two-stroke.htm

Re: NO START!!

Leon Swarmer /

doesn't sound like compression to me. Any engine left at top dead center will leak down. Do you have a compression gauge? I bet it would show OK. I'd be looking at timing issues if the little beastie is backfiring. Leon

Re: NO START!!

Matthew Ciniello /

where can i find some information on adjusting the distributer/magneto. I think my timing points are way off causeing my no start and backfires.

Thanks, matt

Re: NO START!!

Leon Swarmer /

Matt,

The timing on my peds vary from 18 to 23 degrees before Top dead center.

If a PO worked on this and was thinking 4 stroke it might be set for about 8 degrees.

that's what I'd check first.

Leon

Re: NO START!!

Leon Swarmer /

ps have you seen this page ..even a piaggio semi;;;

http://piaggiodreirad.de/18336.html?sessionidkey=sessionidval

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