When you are at the main menu go to options and in cheatcodes type in "clappedout" no spaces needed.
Go to cheats clickable on the options menu and
type in "clappedout".
All Supercross Tracks And All National Tracks
For Supercross, enter STUPERCROSS, and for
Nationals, enter ECONATION in the cheat entry
screen under "Options"
To get all machines, type MINIGAMES in the cheat
entry under options.
Type in sandman under options.
Enter WRECKINGBALL as a code. Alternately, play
the Ocotillo Wells track in freestyle mode. Get
to the purple stunt competition marker then look
for the nearby row of power lines. Follow the
power-lines to the west to reach the bowling
Enter BIGDOGS in the cheat entry screen.
All Freestyle Tracks
Enter BUSTBIG in the cheat entry screen.
Unlock 500cc Bikes
X, X, X, X, Square, L1, L1, R1, R2, R2.
Pro Physics Cheat
Go to options -> cheats and put in code SWAPPIN
Enter squirreldog at the cheat screen to unlock the 50cc bike.