Driving Tractometer

[WilliamTO-35]

My '55 Ferguson TO-35 has a tachometer/speed indicator that I believe they call a Tractometer, or something similar. It was originally driven by a cable from the back of the generator. Since my generator has long ago been replaced by an alternator, is there an easy way to drive the tractometer ? I see reproduction units for sale, but apparently they all drive from the same generator cable.

 

[JMynes]

I added a digital tachometer to a motorcycle once. It was simple to hook up, power, ground, and a sensor lead to the coil. Of course, that was spark ignition. I've seen other tachs that use a sensor on an injector line that senses the "pulse" in the injector line. I think one of these methods would be easier than trying to drive a cable driven tach, but as I recall neither method is cheap.