piston rings

I am in the middle a top end and cylinder base overhaul of my R90/6. While looking up specs to check for piston ring wear limits (as in gap between the rings and the ring groove in the piston) I have come up with a bit of a surprise. I have several sources which I have crossed checked for the...

I was going to size my rings yesterday and then assemble the top end I finally have everything cleaned, honed, and ready or so I thought the bike is a 1971 R75/5 pretty clean internally as it sat for 20+ years I've measured out the cylinders and everything has low wear on it and measured out...