Just recieved my piston etc. Back together and fired up However Has never run since I purchased so have some rough spots. Like: Idles fast,Then real fast, Then backfires.,? Timing, Carb adjustment Throttle? Any good place to start? Thanks

 

Did you replace the crank seals? Very important that you bleed the head of any trapped air in the coolant system if you haven't already done so. Plus if you haven't installed a carb kit,I'd do that. Erratic idle is usually because of leaking crank seals, head or base gasket leak or carb problems. Thumb throttle needs to have 1/8" slack only. The cdi module controls the timing and advance for the most part along with the stator timing.

 

Went back to carb and found floats set to high as in not enough feul in bowl. Idles steady but to slow and sluggish when applying throttle. No backfires now

 

I still wouldn't dismiss crank seals as a problem if it still doesn't run right.