I have a 1980 KE100, the spark plug wire is pretty well shot. I ordered an aftermarket coil (that's all that is available) but it has 2 leads, mine only has 1. The new one has a black wire AND a green wire going into terminals on the back of the coil. Which one/ones do I use? Can I just ignore the Green one? Or does it need to go to ground? Please help! And thanks.