My first bike was an old 89 ninja 600r, was a great starter bike and i feel like it didn't have near as much power as the new i4 600cc bikes. It was also very light to help teach me how to handle a bike around a corner. I also grew up riding dirt bikes and snowmobiles and just about everything else with a engine.
I also believe that a bike is only as fast as you make it. A liter bike can be as fast a moped if you have good self control.