I have decided to revive an old atv, it s yamaha badger 1992-1995 yfm80d with a 80cc motor.. it turns over but nver gets going, I have good fuel delivery, good spark. & good vavle movement. However I have noticed air pressure built up in the crankcase, when I drained the oil it was full of fuel & thinned out. My suspecion is that the rings are shot, allow the fuel and compressed air pass the piston. not allowing the engine to run. what do you think? any one know a good atv tech forum or parts for old atvs?

Thanks,
Thomas

 

I think you have it right. The rings are shot.

 

I would say your assumption is correct..most likely the rings....I think you could also see if it had compression, or the correct compression and that could back up your theory.

 

give that little guy a compression test and see, but it sounds like you hit the nail on the head

 

Well I fixed her, and it wasn't the compression. it was the crankcase vent hoose.. it was clogged with damn dirtdobbers. after I unglogged it it cranks right up, but I can't keep it runnign with out throttle. carb is clean just needs adjustment I'm sure. thanks for your help guys

 

WOW GUYS HE DID NAIL IT ON THE HEAD... RINGS OOOH YAEHH.. oh wait? VENT HOSE?? WELL DAMN!!! i guess u should know what ur talking about first... im sorry but it pisses me off when u guys agree on something that isnt even true.. people do it all the time on this forum and it pisses me off beyond BELIEF!!! hey man my 4-wheeler wont start.. ITS UR EXHAUST ITS BLOWN OFF.. wha?? YEAH BUY ANOTHER ONE... huh?? YEAH I AGREE!!...huh? DITTO!!...

 

OK, you can calm down a little bit there captain......... The symptoms that were described in the initial post pointed to the rings being shot. We didn't all go over to wgonfan's house and look the quad over ourselves so what was posted was all we had to go on. 99.9% of the time the reason everyone agrees on a solution is because the symptoms that are posted match a problem that we have encountered before and just might have a solution for. Therefore, if you have a problem with us trying to help others out by supporting another fourm members conclusion then you can go ahead and take your Jr. High temper and cry to someone that cares. We aren't here to make you happy, were here to help the people that have issues with their machines and want our opinion.