there is a switch on the throttle, then one on the carb (or rail if mulitple carbs) like the last post said, if the switchs don't synchronize right it stalls the ignition. It is for safety, stuck frozen slide, throttle cable breaks, etc. to overide it, just unplug the switch at the carb, and plug the wire inline. You can test to see if it works, hold the pivot on the throttle from coming towards you. rev it up slowly and the engine will stumble and not let it go over 4,000 rpm. Normally if you squeeze your throttle you will see the pivot pull toward you before you actually open the carb slides, thats what you want to hold. try it. I leave mine on just in case there is an incident. I believe (not sure) if the carb slide sticks after you let off the throttle, the computer sees the throttle switch close at the handle bar, and not at the carbs, its then when it goes into stumble mode. its like a stutter box for drag bikes.
