I can also offer this observation: I see piston kits for these bikes sometimes that have 2 dark rings (these are usually cast iron) for the top 2 rings. They work fine, although I doubt the top ring will last as long, especially with ethanol-laced gas. The chromed top ring has long been the "standard" design for many engines, as it is very hard and resists carbon scratches in operation: it also needs very little lube once properly seated/sealed against the bore. Cast iron rings need a little help (lube), and were (are?) common in 2-stroke engines of days gone by because they are cheap to make (and 2-stroke engines used to be 'cheap' motorcycles, back in those days).
