To unlock all the tracks, enter your name as "cdnalsi".
For mirrored tracks, enter the password "cesrever".
At the start of any race, put the gas all the way up. As the annoncer gets to number one in the countdown, slowly release the gas. It takes some practice, but with the right timing, you will cruise ahead of the pack to first place!!
For tiny bikes, enter your name as CTEKCOP.