Hi Dave, i know a hotrod guy or two that have done engine dyno and then proceeded to do the rear wheel dyno. they found that the drive train differences were very profound. one of the guys had higher engine HP/TQ but ended up with less at the rear wheel due to frictional losses. i think the variance we see are the diffences in each bikes friction. there are many parts to consider. trans, T-case, wheel bearings and i would imagine the more your bike is broke in the freer it will spin - to a certain point. a new bike on the dyno will have more grease in the bearings, everything will be tighter because its new, hence more friction. someone with one summer of hard riding like me may actually have higher HP/TQ at the rear wheel because i'm all broke in. i put on 11,000 mi this last summer after i bought it new end of march. it seems to have more snot now that when it was brand new. it would have been nice to dyno it and then do it now to see if there is a difference. if anybody has done this plz let us know the results.