[Major Dad]

I have a couple of spare Tachos which I don't know if they work or not. My car is a Feb 1972 S, Oil Flap model with CDI. The spare Tachos are 1971/72.

Could I just hook up the Tacho to the CDI box or coil in the engine bay , and any ideas of how to do this? What wires to what ? I don't just want to remove the existing tacho ( which works but has an incorrect red line and is not silver dot ) as the wires onto it behind the dash are fragile/ brittle.

Thanks in anticipation !