By the way the magneto is for a mini bike not a car. Im sure thats important.

hmmm ok. looking at the diagram now... the red wire connectes directly to the key under "IG" and that is the only wire that goes dead if you turn the key from the "on" to "off" position. The green wire goes through the "E" on the key, to the start switch, through the battery, and finally to the starter where it grounds.

so i am assuming i put a switch on the red wire and connect it to the frame? Won't this blow the magneto?

Is a switch rated at 6-12 volts and 35amps ok?

Thanks,
-CJP