All these cheats need to be added as your name:

 GHOSTRIDERS  - All bikes and riders will be in ghost mode graphics
 REDJOCKS     - All the riders will race with nothing on but red
                jockshorts
 BEAMTEAM     - Nine new bikes all with different paint jobs
 !SCOOTER!    - Drive a scooter
 !MAAATE!     - Get Doohan's NSR '94 #4
 !JUNIOR!     - ?