From my thinking in the early seventies when they first came out with these when I worked Yamaha was that anything above 55 hundred was just pot luck....and especially with the pressed crank twins.......the ole RT1's never showed 7K+ for redlines which I rode in Florida for a couple of hundred thoudsnd miles and were only a single and had a wide ratio trans....always though to myself as I worked on these in the 70's and 80's was the revs were way above any rational and just for HP sales garbage ....and that the ignition timing was set for high revs and left everyone reving the hell out of these things with redicilous low highway gears ......instead of being set right 2000 to 4500 being a decent running machine geared correctly..sometimes with revs above that if needed....but still overly compressed for at that ....not a hot rod as everyone wanted even then though...that's why there are still around...they parked them...at least for now for the zoom zoom croud to hose them ......ah what would I know..LOL
Lunacy to make a hot rod out of these things when there is so much else to be enjoyed if set correctly...xsjohn