Didn't know what year your engine was. The older ones have a compression valve on the side of the cylinder to make it easy to push start and to kill the engine. If you have some wires coming out of the mag area other than the big spark plug wires, trace them from the mag and see where they go. If they go to a switch, then that would kill the engine. If the switch that you might find does not kill it, then get a small test wire and clip it on a ground area of the bike and as it is running touch the wire and see if it kills it. If so, the switch you might have found might be no good. Take a look at the three way switch and see if that wire comes to it from the mag. If so that switch might not be good. If only the head and tail light wires go to that 3 way switch, then it is the light switch for high and low.