Ive seen 185 on my busa speedo and ive bounced off the speed limiter in 6th gear on my R6 while it was reading 187-184 inbetween bouncing off the limiter.
How accurate that is, i will never know, but shortly i plan to use my friends GPS on my busa to determine how off it is with the gearing. its only a +3 rear sprocket.
Typically on the busa when im on the freeway, i will surpass 150mph quite frequently, because it is that easy to do, haha.