Enter "2468G0A7" as a password from the options menu to unlock all bonuses.
Enter "JIH345" as a password from the options menu. The only way to disable this code is to reset the game; make sure to save your progress before doing so. Also, this code will cause your bike's handling to decrease considerably at higher speeds, and you will be more prone to bottoming out when landing. Be careful if you plan on using it during your career.
Successfully complete all the Freestyle competitions to unlock Officer Dick and the police bike.
Successfully complete Master Supercross to unlock Maggot and the Slipknot bike.
Successfully complete the entire MX career to unlock the Speed Demon.
Successfully complete the entire Freestyle career to unlock the Trickbot.
From your starting point on the dock, back up slightly and look to your left. Ride over to the set of jumps that are at the other end of the barges. Once in the area, ride over the jumps to your left until you reach the jump that is directly left of a palm tree. Past this jump are two landing slopes; one that is directly in front of the jump next to the palm tree, and one that is behind it and to the left. Ride over to the second slope and face the right hand corner/side area of it. Continuously ride into this area, trying to push your way through it. With some speed and the proper placement, you should be able to ride through the corner of the slope and ''fall'' through the ground, eventually re-spawning back onto the dock where you started. During this ''fall'', you will also be able to string together as many tricks as you wish for an insanely huge multiplier without the fear of crashing; when you re-spawn back onto the dock, the game still acts as if you are in the air, Note: Be careful with the gas and brake/reverse, as the game also acts as though you are on the ground as well. When you are done with your multiplier, speed off into the level as usual. If done correctly, when your jump distance meter appears it should read more than six hundred feet. Note: Repeated use of this glitch to increase your multipliers may cause the game to crash. Make sure to save your place immediately after you have achieved your new jump distance. As with any glitch, use it at your own risk.