Maybe someone out there can help. I have a 1988 lt80 that my son races out here in Vancouver Washington. I have the keihnin carb, modified clutch, hetrick pipe, and a mild port and polish. The compression reads about 120 psi after motor has been warmed up. The bike takes off like a rocket, but when it gets warmed up it looses power, boggs down not allowing the user to go full throttle and eventually dies. After sitting for a few minutes it fires up again and is fine, only to repeat the problem again. I have checked the carb for dirt (multiple times) it is fine. The plug looks alright, I am running a 115 main jet and dont think I should have to go any higher (there is no buildup on the plug). After reading the forums, I thought it may be due to the petcock valve, so I went with an after market High flow Banchee petcock, still having the same problem. Could this be an electrical problem? The starter died about a year ago, so I removed it completely and replaced with a pull start. The only things I havent replaced yet is the coil and the stator. Any advice would be much appreciated

 

Boxerman - I did have a coil go bad once with simular problems, but the quad would not start back up for a half hour when the coil cooled down. I would check the coil output and it would read zero. The coil was too hot to handle with your hands as well.

I have also seem simular problem with Stators as well.

I think you are on the right track.

 

Thanks for the advise, I will give it a try tonight.