Full list of all 36 Motocross Madness achievements worth 500 gamerscore. It takes around 8-10 hours to unlock all of the achievements in the base game.
The base game contains 30 achievements worth 400 Gamerscore, and there is 1 DLC pack containing 6 achievements worth 100 Gamerscore.
Seized the top spot on one of the club walls
Crashed while riding with at least 100 mph
Completed 3 Avatar FameStar weekly challenges
Played any splitscreen match
Finished your first club task
Unlocked all Egypt race tracks
Bought 1 new upgrade for any bike
Reached skill level 2
You've won your first gold medal
Completed the tutorial
Reach skill level 20
Buy your first new bike
Buy all 6 bikes
Get dressed in a matching outfit set
Unlock all Australia race tracks
Unlock all Iceland race tracks
Reach skill level 10
Earn $100,000 in cash
Score first place in Rivals
Get at least 5 seconds of air time
Donut for at least 30 seconds
Drift 400ft
Slipstream for 800 or more feet
Wheelie for 1,200 or more feet
Get high score during Trick Session
Land a trick worth 20,000 or more points
Score a slingshot distance of 2000ft
Get a gold medal in every event
Finish 5 bike club tasks
Collect all skulls around the world
Win all the Trick Jams events
Win all the Stunt Race events
Perform an X, Y and B combo within one event
Unlock 5 Trick Jam skills
Unlock all 10 Trick Jam skills
Drift for 2,000 or more feet on any of Trick Jam tracks