Manx TT

Sheep Mode from Cheers joe_saturn@hotmail.com
When you are asked to select what transmission AT/MT press UP,UP,Down,Down,Left,Right,Z,Y

Super Bikes from Joe_saturn
At mode select press Left shoulder + Right Shoulder + X + Y + Z simultaneously

Music select code from Scott Roberts
At main menu , press and hold X,Y,Z and select arcade, when you hear two confirmation tones , release. select track, change music with 3-D pad/ D-Pad.

To get the Dark Rider on Arcade mode from Edward J.D.
Play arcade mode, at the select transmission screen, enter left, left, right, right, z, y

The following codes are confirmed for the US version

Sheep Mode from David Everly
At any of the Transmission screens press Up, Up, Down, Down, Left, Right, Z, Y then choose your transmission and prepare for the most hilarious time of your gaming life!

SuperBike Access from David Everly
At the menu screen R+L+X+Y+Z and you'll hear a the announcer say "Great!". You now have access to the superbikes and the SuperBike Mode!

2nd Intro from David Everly
To watch the second introduction watch the first then watch the game demo then again watch the introduction again but this time it will be slightly different. Showing Sega's motorbikes only, that actually appeared in the real Manx TT race.

Pull Wheelie's from David Everly
This is more of a tip than anything else but anyway you can only do them on the Reversed/Mirror courses. The first place you can pull a wheelie is in the first R/M track. The second long turn right before the tunnel get your bike speed to around 180 mph before you reach the jump. If you don't hit and walls that first hill your bike will pull a wheelie. The 2nd place that you can pull a wheelie is in the 2nd T.T. R/M track. You again must keep your speed around 180 mph, (this can be hard but can be done with practice) when you reach the shaded area with tree's and you go over the first hill make sure you hit the second hill around 180 mph then on the hill afterwards you will pull a major wheelie. This doesn't nothing to the game it's just fun! Ohh, it's also recommended that you use the superbike code (press R+L+X+Y+Z at the main menu screen) for this to work properly.

Great Start from Rich Gustafson
For a "Great Start", hold the RPM's between 8000 and 10,000. This should have you accelerating faster than if you just hold down the gas before the race starts.

Tantalus Bike in Arcade Mode from Hypersega
In arcade mode when your selecting transmission press L,L,R,R,Left,Right,Left,Z,Y,Z and wait for the time to run out and you should see a gray bike with the Tantalus logo on the bike riders back.