Backfire problem fixed Duramax 440cc Vitacci Pathfinder

Sheared the flywheel key.
replaced the key and reset the flywheel to 65 foot lbs.
also changed the TAV driven spring to yellow and put it to the low gearing setting. was getting no high gear and now it shared the belt if too fast on the gas pedal; going to low helped but it'll still rip the belt if you don't coddle the throttle...but its running..
new 34mm carb..
also put the hub spacers and slicks on the front...