this is the quickest 50cc bike available once its de-restricted. restricted mine did 35mph on a flat with a full tank of fuel. de-restricted mine does 75mph regularly and out accelerates any other 50cc bikes. i have kept up with 125cc bikes (with difficulty). i recomend a sports exhaust and a sports carb because i have heard reports of tzr50´s going past 90mph (this will require new gearing but its not very expensive). much quicker than an aprilia rs50 i have out dragged one of these that had a sports exaust before(mine didn´t have a sports exhaust)