Hi,
I have had my Koso instrument unit's rev counter fed from the crankshaft position sensor's wire. But I couldn't set the Koso up well and it was never accurate (showed about 13k when it was doing about 10k - as evidenced at the rolling road session).
At the rolling road session, they just slipped a sensor between the two wires of one of the spark coils and they had the rev signal. So I tried the same, took the signal from one of the coil wires, and now I have a rev counter that when set to 4 cylinders, 4 stroke on the Koso, always shows lower revs than it should. And I mean massively lower (about half maybe).

Where should I get a signal from? I don't have the original bike rev counter feed any more on the loom unfortunately.

Any ideas?

Or do I have to set the Koso unit differently?
Thanks!
Gergely

bike tachos are fed from the negative, ie trigger feed of the coils

probably need to experiment with the settings as bikes run twin wiring setup with wasted spark, so they quite often read half the number of revs on electronic units.

look at your ecu plug and find the Yellow/black wire (it's in between the brown/red for the air induction system and the black/red for the exup)

Use this for the koso, that's the wire the stock clocks use, if you've completely removed the wire and pin, then it may pay to obtain another, failing that adjust the settings on your koso and use the earth on a coil.