Re: One of the rings is broken on my bike... how do I get more power from it?
Politely ask your 'helper' to leave your engine alone. "Thanks, but I'd rather do it myself so I can learn" would be one way to tell him.
Buy and install new piston rings. For less than the price of two gallons of gas you'll be on your way. Look for the anti-rotation pins Joe described. The ring gaps must align with them before installing the piston into the cylinder.
Trying to run the engine with one ring or a broken one is asking for engine failure that will cost you lots more than the price of fixing it right.
Age and Treachery Will Always Triumph
Over Youth and Skill & "Charlie Don't Ride"