I replaced my thumb throttle with a twist from Motion Pro. Then the bike won't start. I checked the manual and it said to disconnect the 3 wires going to the controller and try again. Well, it worked, The bike started. So, my question is: What does that little black boc they call the controller do? Do I really need it?

 

It's part of the TORS (Throttle Over-Ride System) It cuts spark if the carb ever gets stuck open. Your old thumb throttle had a switch in it that tells TORS if the throttle is open or not.. if the thumb throttle is closed but the carb is open, it cuts spark. This would keep you from going out of control if the throttle got stuck or if you tried to start the motor with the carb stuck open.