The bikes top speed is 61 MPH standard .YOU can increase speed by replacing the front sproket to a 13 teeth asaposed to the 14 teeth standard .And the rear from 47 to 40 teeth .this will give you a top speed of 65MPH .but more important is it will increase your top speed going up hill and in head winds .you can replace the main jet to 87.5 standard is 77.5 with standard exhaust