Have a 07 Sunl 90cc, this thing has been a lot of fun for my son, so long as you don't consider the down time. With that said I have an interesting problem with it. Have spark and fuel but it fires at the wrong time. I know it is the wrong time because it spins fast then fires and slows down (the starter) then spins fast and spits and back fires. The CDI is new, so my thought is that there is some kind of timing chain/belt that is out of adjustment. Where is it? Where are the timing marks? Any help would be appreciated.

 

Welcome to the forum jrsmithliverpool!

The timing marks should be on the fly wheel and the inside cases. The cam marks will be on the cam.You will want to make sure the cam is timed correctly as well as the spark..