To my knowledge neither has had upgraded valve seats
I've had the 74 R90/6 for couple years maybe put 1000 miles on it. Use primarily non ethanol fuel
JUST bought the R69s. Non running but "ran when parked" 15 years ago. Very low compression, pulled the jugs, rust in exh chambers. Intakes very burned. Valves and gaskets ordered. Hope seats ok.
Any advise on this?