building one working motor from two "80"cc motors. due to bolts stripping out. here we go, first the motor stripped a main bolt. so we replaced with larger bolt after tapping and threading new. now it did it again with the larger bolt. so i took the time to replace the bottom end of the motor with another i had laying around. removed the jug and piston from motor 1. used the clutch and carb from motor 1 on motor 2. got every thing adjusted and put back together. installed on the cruiser and guess what. this piece of **** wont start. tried every thing i could thing of in my wildest thoughts. its got spark, plugs wet from gas, intake manifold is tight (ie no air leak). what the **** am i missing? sparks like dancing on the sun, more than enough gas to power a car, compression enough to suck your eye out. what the **** am i doing wrong guys?