Hi , I have an 2001 Lt80.. with an FmF fatty pipe , wiseco 0.30 over piston. my problem is i have never jetted the main jett it's still stock but i lowered the needle clip to the lowest..my question is can I put an # 110 main jet.. because.. after running 15 minutes... the motor switches off..and it backfires when starting it back up.. when the motor cools down it starts back....

 

My first thought is a bad plug and/or plug cap. I/we duct tape them down.[img]i/expressions/face-icon-small-wink.gif[/img]
I highly doubt jetting is a factor but you should see what color the plug is.
It'd be rare, but this is smelling like a coil problem. heat/off...cold/run is usually electric.[img]i/expressions/face-icon-small-sad.gif[/img]