If anyone is interested, it's an open circuit system, so to wire in the tether kill switch you have to splice one of the wires off the tether (it doesn't matter which one) to either the grey or the black wire coming from the back of the key switch that runs to the cdi, and then wire the other wire off the tether switch to the opposite wire you spliced the first one with. The black and grey wires running from the back of the key switch have to make contact to kill the engine, so the tether switch, when activated by pulling the tether, causes the black and grey wires to make contact, thus killing the engine.