Well I learned on a Honda 125 Night Hawk... And as soon as I felt very comfortable with the Honda I went straight to a 04 Ninja 636...At first it was a little difficult to get adjusted to so much more power and clutch, but in a couple of hours I was riding it all around... So in my opinion you should start off with like either a 125 or at most 250.... So if anything Ninja 250r it is...lol G/L