Any Bike on any Track:

In the "Big Game" mode; once you have earned enough money to buy a level 3 bike, at any time during any race, pause the game and quit. Then go to the "Thrash" mode. You should now be able to select the level number (1 or 2), any bike, and any course. Make it to level 4 in the ‘Big Game" repeat the above sequence, and it will add level 3 to your selectable levels in the "Thrash" mode.
For example: You can play using the firecracker (a 1st level bike) on a 19-mile long course, which is a level 3 course. Trust me; this is a long knockdown-drag out race!

Easy 2X Blast:

Hold down L2, and then hold down R2, and let go of L2. If you do this correctly (it's not very hard) your view should have just zoomed out a little and you'll see the "2X Blast" sign where it usually is. The "2X Blast" will stay on until you let go of R2.

Avoid a Ticket:

Right when a cop stops you, press start (pause) and restart the race. This will keep you from getting a ticket and save you cash.

Hitch a Ride:

Get behind a car and pop a wheelie (press X twice). You can jump up on the car and hit the brakes. You'll be moving along with the car for some serious speed!

Put That Wheel Down:

To do a continuous wheelie keep pressing the "X" button until you crash or have had enough "one wheeled" action.

More Tunes, Less Racing:

Go to Juke Box and choose a song you like. Then select 'repeat' and go to Big Game or Thrash, do everything you need until you hear the countdown. A voice counts down; "3, 2, 1". Pause the game at 2 and you will hear the music keep playing. This works on any track and is great if you want to here the music but don't want to race.

Hang On?:

Controller configuration must be on 2. During any game, on any level, with any bike, while going around a curve, keep holding the X button and hold down the Circle button. It gives you better traction and keeps you from sliding and helps you avoid a wreck. It may also give more acceleration.

Get Chased by Tons of Cops:

Go backwards on any tracks soon you'll be chased by a lot of cops.

Buy Any Weapon:

When you are buying bikes press: Up, Down, Left, Right, L2, R2. To use that weapon press, in the middle of the race, Select and Triangle at the same time, and look in the upper right corner. Were you just saw a hand, there should now be a weapon.