Hey Zeus.
I havenīt tried an MC18 Tacho, since i donīt own one.
Also they arenīt particularly easy or cheap to come by.
But atleast for testing the rpm output of the PGM-II it would be very usefull.
also purely judging from the picture, the mc18 tacho seems to be of a bigger diameter, than the mc 16 tacho.
so fitting the mc 18 tacho into the mc16 gauge cluster might be dificult.
Just knowing, in what way, the RPM signal is transfered on the MC16 and MC18 would already be extremely helpful.
By that, i mean things like variing voltage, current or resistance or even PWM values..
if i knew, what values the PGM-II unit outputs, and what values the MC16 Tacho expects, testing both the cdi and Tacho and then building a "Translator" using an arduino shouldnīt be too difficult.
That would acually be my prefered method, since i wouldnīt have to alter the mc16 gauge cluster that way.
As for the Speedo cable, iīd have to measure, where i think, the cable is supposed to be routed.
Donīt have a great way of doing that, at the moment, since i donīt even know, where itīs supposed to be routed, yet.