We now carry a new brand of keyswitch which are polished metal. In the locked position, the magneto is OFF (grounded out). In the ON position there are a pair of terminals connected. There is also a third position, START (momentary). For operating with no battery, you can use as few as 2 terminals. The switch mounts in a 13/16 hole with the provided hardware.
A: Accessories (lights, etc.)
S1 & S2: Closed when turned to 'starting'; 1 to ground or power depending on your set up.