I had my K-Pipe up to 63 once going down a steep hill, otherwise, 50-55, depending how long a stretch. But that is all in the past, I replaced the 125cc with a GPX 190cc engine, easily gets up to 70, and it's got more, but I'm scared, the bike ain't made to go that fast, got a YSS shock coming, maybe that'll help my fright, I'm thinking I can do close to 80, a smaller person that could get into a good tuck, maybe 90, I doubt that it would do a ton