Road Rash Codes -

Walk around:
Brake until your speed is 0 MPH. Press L1 + R1 + Up. Your racer will dismount from the motorcycle, and can explore the scenery.

Diablo super bike:
Dismount your bike at the start of the peninsula. Run to the end to get the Diablo super bike.

Glitch: Floating bike:
On the Ridge Run race on the third level take a right instead of a left. Stop there to see a bike will be floating in the air.