Cam chain jumping a tooth

[Big_Phil]

Have a buddy that has the Kibblewhite kit and springs and it still spit 3 shims out when it backfired.It may be better, but its not foolproof either.

View attachment 166352

Curious to what causes a backfire like that? Don’t think I’ve ever seen one of these sleds do that.

 

[NYTurbo]

Excess fuel igniting in exhaust I assume.