Originally Posted by pop-leon
I have a new 60cc sky hawk bike engine.Every thing is lined up good and my bike peddles easy with clutch in free wheeling position. MY problem is that when I release the clutch to start the engine it won't turn over and you can't peddle it. The engine turn's over fairly easy with the plug out. (HELP)
What I would do is remove the chain, remove the magneto cover and use a ratchet and a socket and turn the engine over and see it it locks up. If it does, change to a NGK plug (might be a different in the reach) you need to do this and a new plug lead anyway. If that fails, remove the head, and try to rotate the crankshaft. If it doesn't lock up, add a extra head gasket, maybe 2. While you have the head off...mill both head and cylinder, using some where around 250 grit paper on a flat service (glass). Only remove enough that you can see that the surfaces are flat. I have never seen a head that wasn't warped.