Motorcycle Repair: ignition, crane hi4, fire ignition

Question
I am hooking up a tach to a single fire ignition. The modual is a Crane HI4 and the coil is unmarked but does have three post for wires. Instructions say green wire from tach goes to neg post of coil. Which one is the neg as there are no markings? Thank you much. Skip

Answer
The single fire coil has three posts. Usually the one in the center is the positive one, but check with a test light to be sure. It should be hot when you turn the ignition on. The other two posts are the negitive. SInce you are trying to connect a tach to a single fire ignition you will need a adapter for the single fire ignition or the tach wont work unless it was designed for a single fire
Good luck and happy riding
Mike