i would tear the top end off and see whats going on for sure. sounds like something is for sure messed up in there. and i definetely wouldnt run it anymore. you could end up messing up the crank or really tearing up the cylinder wall bad. also, you will notice no significant increase in power by boring. boring is basically to clean up the cylinders when something happens to them. with that being said, i would just go to the next size bore for your cylinders whatever it may be.