If you want, I can also for Motocross Madness 1 (based on reverse-engineered format from the game’s memory) or write the password generator code. Just let me know.
Motocross Madness 1 does not have a single fixed password for Dexto. Instead, the game saves progress using profile-based passwords (track unlocks, medals, etc.). Dexto (the stadium trick track) is unlocked by earning a certain medal on other tracks. Motocross Madness 1 Dexto Password