Some barrels have cutaways and the rings need to be spaced so the end of a ring doesn't go into one of them and snap off. I've just put the barrels on a Norton Commando and this is mentioned in the service manual. It says space the ring gap, top to the front, second to the back and oil scraper to the side. The top 2 rings and inch to the left and right of the conrod cutaway.
Well 2 stroke rings have to avoid the ports so they have pegs in the grooves to stop them turning. I don't think you could expect the rings to stay in the same place without the pegs. Ron
