My brother and i were going down i 20 leaving barber vintage fest headed back to our camp site a few years back and we decided to air the bikes out one time. I dont run a speedo or tach on my turbo 750 sohc but according to him we were going 130mph, he had a kaw zx12 at the time. i got his zx12 up to 160mph the one and only time i ever rode it.........yea that was it for me on that thing stupid fast, there was most defanitly some small signs of butt gravy after that one