ok ZB,........ here it goes. the ring & piston should not be remove. unless you need to for dirt, (after bad crash,) or bearing replacement. the ring must seal against the cyl. wall, & must also seal against its bottom surface which meets the bottom of the ring land in the piston. as they wear together, they do develope very microscopic surface coatings of varnish. & as time goes on these are what all these parts seal against. if not in exess, theres nothing wrong with it. removal will affect the performace for a time after, till these coatings get regenerated. the ring's in engines do rotate as others have said, the pinning prevents the very edge of the ring from getting into a port & catching on it. the piston's running clearance in these ringed engines is a little bit looser than an abc engine, there the top of piston is what seals against the wall. less likely to mess up sealing surface in those engine's. the carb cleaner added to the fuel is the best thing to do. .......good luck with this either way you go.