Make sure it has a good tight ground on the frame. All a kill switch does is complete the path for the ignition to ground itself to stop the spark. You should have continuity from one wire end to the other only when the switch is depressed. It will be on open line when not depressed. If you don't have these results, then it sounds like a bad switch. Moose racing makes replica Kawasaki kill switches for under $20.00.