In this video, I get 255 coins in Rainbow Ride. I used an emulator, both for the save states and because the console would probably freeze from performing this glitch. I used the bob-omb glitch to duplicate 109 coins, and in addition to the 146 coins in the course naturally, I was able to get 255 coins. 255 is the maximum amount of coins you can get, because after that the coin counter resets (256 is stored as 0, 257 is stored as 1, etc.). I massively edited it, so you just see the most relevant parts, because it would have been pretty boring otherwise. Enjoy!