[skidlids]

So what would be the safe rev limit with the bigger pistons flying up and down and would reliability suffer if you tried reving a big bore kitted motor to the same level as the standard motor.

Maybe rather than bringing power levels in line we should be looking at Power to weight ratios. If the 620 models were only allowed a 10% reduction in weight (Mainly the exhaust, lights, indiactors, mirrors etc) and the older 600 bikes a greater weight reduction. No need for a Dyno just some large scales.