Moped Army

ok..no pix.. Is this tachometer driven by a cable or does it have wires sticking out the back?

If it has a cable, that cable would go into the gear box and mate with a tiny nylon gear. That gear is turned by something inside your friend's gear box. Trying to adapt it to a no-gear moped is pretty much a waste of time.

Go find a tach that has wires. Two wires would be connected to a battery and the other would be spliced to your stator's ignition coil wire.

I just hooked up a tach and it is fun to watch but of little value unless you are tuning. And it's useless for tuning if you have a variator.