Re: Piston Stuck
Oooohhhh...still a bit sketchy on what you did, and why the rings were removed to begin with. Was this a broken-in engine? If so, I've had trouble in the past reinstalling old/new rings on a used piston: the minimal carbon build-up can prevent the rings from reseating properly, and result in their being a slightly larger resulting diameter than the cylinder. You should NEVER have to force the cylinder over a ringed piston with any more force than some light taps of your palm. NEVER use a tool to do this, ESPECIALLY a hammer. You may still be able to recover. I have actually run temporarily on one ring while I awaited replacements. Post some pics!
If it IS indeed carbon-buildup caused interference, use a new, sharp razor-blade to scrape the carbon off the old-rings and the piston's ring-grooves until rings can easily be compressed manually so the rings' outer faces are flush with the piston's.