My LT50 is suddenly giving me trouble. Everything possible has been done to it including porting. All of a sudden it is having trouble starting when hot. I let it cool down and it fires right up again. Its is almost like it thinks its a four stroke.!? Anybody have any ideas as to why this is and how I can fix it?

 

The same thing started happening with my kids KFX50 shortly after I did the same mods to his quad. It would die while cruising down the trails but easily restart and then it slowly became harder to start until it cooled off completely. It finally seized up, destroying the piston, rings and bore. I figure this was due to the top end being in need of a rebuild and too lean premix. I rebuilt it and am now running 32:1 without any further problems.

Pull the pipe and take a look at the piston & rings through the exhaust port. If it looks the least bit grooved or suspect, pull the head and go from there.