USA Extreme bike
Press [Right], [Up], [B]x2, [A], [B], [Up], [B]x2, [A] at the "Game Mode" screen.

Achievements
Complete the following achievements to unlock the indicated number of Xbox Live Gamerscore points:

Challenge Expert (30 points): 50 Challenges completed.
Challenge Master (60 points): All Challenges completed.
Extreme Bike Collector (50 points): Buy all extreme bikes.
GP: Champion (60 points): Win a Career mode Grand Prix season under the Champion difficulty.
GP: Legend (100 points): Win a Career mode Grand Prix season under the Legend difficulty.
GP: Professional (30 points): Win a Career mode Grand Prix season under the Pro difficulty.
Seeded #1 (75 points): Seed #1 reached.
Seeded #10 (50 points): Seed #10 reached.
Seeded #25 (30 points): Seed #25 reached.
Seeded #50 (20 points): Seed #50 reached.
Seeded #75 (15 points): Seed #75 reached.
Seeded #90 (10 points): Seed #90 reached.
Stunt Mode Rider (10 points): Play a Stunt mode game in multi-player mode.
Extreme Mode Champion (10 points): Win any Extreme mode championship.
Extreme 1000 - Legend (60 points): Win a Career mode Extreme 1000 season under the Legend difficulty.
Extreme 1200 - Champion (50 points): Win a Career mode Extreme 1200 season under the Champion difficulty.
Extreme 1200 - Legend (75 points): Win a Career mode Extreme 1200 season under the Legend difficulty.
Extreme 1200 - Professional (25 points): Win a Career mode Extreme 1200 season under the Pro difficulty.
Extreme 600 - Legend (30 points): Win a Career mode Extreme 600 season under the Legend difficulty.
Accredited (100 points): All rider credits awarded.
GP: Rookie (10 points): Win a Career mode Grand Prix season under the Rookie difficulty.
Finish 50 races (20 points): Finish 50 races (Xbox Live or offline).
Finish 250 races (30 points): Finish 250 races (Xbox Live or offline).
Finish 500 races (50 points): Finish 500 races (Xbox Live or offline).