Re: E-ton 50 starting
If the pipe and the porting don't match you will get a sonic return wave that will push hot gasses into the intake system. The evidence of this is a dark exhaust color in the transfer tunnels. I don't know if this is the problem, but it is the first thing that comes to mind. It also could be a timing issue. If the CDI box is bad, or the flywheel has slipped, or the timing plate has moved, or the coil is partially shorted, the extra advance, especially on a hot motor, could cause this damage.