So, after many years of riding a stock ZRX, I have made a few mods to it. The latest one is to mount a set of gauges from an 86 ZX 900. I had to fab a bracket to mount them and re-pin the connector. The only issue is that the tach reads about double what the engine is actually turning over at. ( 5th gear at 55 mph indicated the tach is showing almost 6 k rpm). What I need to know is how the ZX 900 ICU measured the rpm. Is there a way to step down the signal that the ZRX ICU sends to the tach? Ideals anyone?