The rings are pinned on the piston to keep them from rotating. When you install the cylinder you must have it lined-up or the end of the ring will catch on a port and make a me$$. Over tightening head nuts can warp the cylinder and cause four hotspots and failure. Crankcase is sealed and must hold pressure.

Manuals are available, ask at a repair shop. Check eBay, probably get 500 manuals on CD for a few bucks.