I always love when people say someone's bike couldn't keep up with theirs. How about you swap bikes and try it again, to eliminate the rider's experience from the equation? I've blown away 1200 sportsters and full size Harleys on my America. More than anything the rider was the factor. Pure and simple. My friend Eric with the 1300 Honda VTX? He spanked my ass*. You know why?
He was trying.
*Addendum: in a straight line. I ate his lunch on Beartooth Pass.