Missing something... bikes will run different speed on different days. Atomsphere matters on ringing out the highest speeds. Hot, cold, humidity, wind - even a little can help or hurt... road surface, tires and tire pressure matters too. Since were only talking the difference of a few MPH on the top end just thought I throw this out.
There is a theoretical limit of speed associated with max rpm, gearing and tire size that you just can't exceed. I don't have the time or the inclination to figure this out, however it would be a cool little program for some math genuis to figure all the variables for a theorical speed limit calcuator. Just like long range shooters use ballistic trajectory programs to enter variables(bullet weight, powder, coeffiecnt of drag, muszzle velocity etc.) to find out bullet drop and distance.