Having some trouble with the rev counter on my gk76 not working, tried a second gauge, no joy there..wiring all seems ok too?? Anyone have any ideas or experienced similar issues?

You've definitely checked the wiring splice that goes to the - coil connection??
Odds on it's a bad connection, hence no signal to gauge.

It actually had the same issue and had to open up the wiring harness and found a split.

Did a quick continuity check on the wiring last week and all checked out ok but going to strip the loom back this evening and see if I can find anything

I think the spilce to check will be very near the coils. Good luck man!