Tach signal help 87 Kawasaki gpz3055

So picked up this beater bike and it came with an aftermarket electrical tach that isn’t hooked up. Bike originally had a mechanical tach? Anyways I am trying to find a tach signal to hook this up. I have purchased a tach signal converter for dual coil setup. It suggests tapping into the negative signal from each coil (with each coil having a negative and positive wire)

The problem is I only have a single wire from CDI going to the coils which I am assuming is positive. Does anyone know where else I can tap into the system to get the required tach signal? I can post a copy of the wiring diagram if this will help.

Usually, they get a signal from wrapping the signal wire around one of the plug wires.

+1

Tapping into the negative wire on the ignition coil is usually only an option for bikes with points or TCI ignitions. CDI bike will usually need the plug wire wrapping method.