I too am a novice on these bikes. My best guess would be a carb issue of some type. possibly an intake leak at the carb/manifold junction, possibly something stuck in the carb jets/passages. I just went through this with a "new to me" LT80.

Best of luck

 

The compression is good. In fact, it's higher than what stock comp should be. Has the head been shaved?
Either way, Comp isn't the problem.
It's a fuel delivery issue. Choke on usually points to carb.
I donno, you said you had the carb off many times.
I'm presuming that you removed the jets and sprayed/blowed/etc..
Maybe try boiling the carb. It's worked for others.
http://forums.atvconnection.com/kids...-new-post.html

 

Ok I will try that. Does boiling the carb involve what it sounds like. Im assuming I should take the carb apart and boil it in water

 

Yep.

 

Ok the carb is in the pot. Also I noticed when I took the carb the insulator that goes between the carb and manifold the o ring is very hard and brittle. I tried to take it out and it just flakes away. Im curious if that could have been part of the problem. Its almost like theres no oring there

 

OK I got it back together, Now it doesnt even try to fire off. I pulled the plug and it is bone dry. There is no Oring gasket between the carb and the insulator. I dont know if that could be the issue. Im fairly sure I put the carb back together correctly. Im so disgusted with this thing I wish I had a quarter stick That would fix the whole damn thing

 

It needs that o-ring.
I have them here if you cannot get one locally.
BTW, I'm close to Erie Pa.
It'd be quite a ride for you. But if your into a road trip, we can do it on a weekend.
Oh yea, you'd need to bring Lobster if you have a local place.. I'll buy!

 

Yeah That is a little bit of a haul. If I cant get it going then I will load it up and make the trip. I have the part number from the manual for that o-ring. I will stop by the local shop tomorrow and see if they have one. I guess ill also take the carb back off and make sure I put it together correctly. Ill post again tomorrow evening.

Thanks for your info so far.

 

I got the o ring in and also replaced the plug. Boiled the carb last night. Took at least 1 minutes of constant on the starter before it would try to start. When it did start I would shut it off and it would start right back up when I tried. then it would be real hard to start again. Once its started it will run without the choke on but the idle seems to high and when I turn the idle screw it doesnt affect anything. It also will only seem to run with the fuel **** in the prime position, If I have it in the on position it will run for a few moments and then shutoff. Im just curious if the previous owner has messed this carb up.

LT80, I wonder if instead of me making the trip up if I could ups the carb to you. I would also include a return label as well. I really need to get this thing running before the 17th. I need it that weekend at the track. I would also pay you of course for any work you do.
If thats ok pm me your address or you can give me a call. My number is 240-818-1247. I can get it out tomorrow that way you would have it on fri

 

From what you said, It's dumping fuel in IMO.
Umm....Petcock: In prime, fuel runs constant. In on position, it opens when it gets vaccum. And even without vaccum, it should run more than a few seconds after being switched from prime position...Maybe 30+ seconnds or so.
Carbs do go bad. Not common but it happens.
How about you e mailing me a ups thingie and I'll send you a carb off a running machine and we'll go from there?
I'm finding out that more and more carb problems are arrizing.
Ethanol I think is the culprit.