Actually, you're better off going to any one of the "Machine Test" tracks and doing the settings adjustments there.
If you go to a regular track to do the adjustments, you either have to do the race (at a big disadvantage, as you've just dropped your HP, and seriously risk losing), or quit the race (and get credited with a loss anyway). It's bad either way. The test tracks have no such liability - you can quit with no penalty.
The test tracks are accessed via the main menu - the same one with the East, West, etc., cities.
Good luck
GKP