Career completion:
Enter CLAPPEDOUT as a code for the "Character Completion" option at 
the "Cheats" screen. All bonuses in the game will now be unlocked. 

50cc Class 
Enter SQUIRRELDOG in the character completion field. 
 
Open Up Pro Physics  
Enter SWAPPIN in the character completion field.  

Bowling: WRECKINGBALL 

Expert AI: OBTGOFAST 

Freestyle Tracks: BUSTBIG 

National Tracks: ECONATION 

Supercross Tracks STUPERCROSS 

Unlock All Machines: MINIGAMES 

500cc Bikes: BIGDOGS 

Bowling mini-game:
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 lane. 

Reset vehicle:
To reset you vehicle (dirt bike, monster truck, trophy truck, etc.), press L1 + R1 
during game play in freestyle mode. If you try to do this with the biplane or 
helicopter, you must be flying slow and close to or on the ground. If you have your 
propellers broken off, you can also do it there regardless of the speed. If you flip 
your trophy truck or monster truck, you can do this to get up faster without waiting 
for the game to do it for you.

Bailing:
Enter the options screen and set the "Throw-Away" trick to be used. Save the 
game in the options screen and you will be able to bail whenever that trick is used 
during game play. 

Bunny Hop:
When riding on flat land, Press Up/Left or Up/Right + Square while going in a circle.

No Hander:
You can do a No Hander stunt off a small jump and land while still doing the trick.

Wheelie in monster truck:
Reverse then gun it, or hold the clutch and the gas. Let go of clutch keep holding 
the gas.

Easy points:
When you do the longer tricks, Catwalk, etc., end them with "No Handers". This 
cuts the harder trick off sooner and gives you more points. Note: This works best 
with Catwalk. 

Use a couple No Handers in a row. This will get you many points. This works 
especially well when you add another trick to it.

Do a Backflip (Up, Down) with a Lazyboy (Circle + Down) to get a lot of points.