Electronic Tach Question

[jgordon]

I have an 1150 head on my 83 1100 and i got an electronic tach from a 90 gsxr 600. With the Dyna coils it will run for about 15 minutes and then I lose the cylinders that the tach is hooked to. I swapped to the stock system and it won't even run at all on those two cylinders. The tach is hooked up right and works.

Why would it run for a while and then drop out?

This is the only way that the tach will work.....

The tach is a three wire tach.

Black / White = Ground ( Ground on frame )
Orange / White = Pos. ( Pos. on coil )
Black / Red = Sensor ( Neg. on coil )

I hate electrical stuff

[kungpaodog]

Sounds like the sensor could be bad, but I'm not a big fan of electrical work either. That's assuming the tach really is in good shape.

[MinnesotaTim]

You're tapping your tach signal off the ignition coil??? Is that standard on motorcycles? In my experience with ATV's and watercraft the tach signal is tapped from one of the unrectified outputs of the stator. Are motorcycles different, or are there multiple variations?

[jgordon]

You're tapping your tach signal off the ignition coil??? Is that standard on motorcycles? In my experience with ATV's and watercraft the tach signal is tapped from one of the unrectified outputs of the stator. Are motorcycles different, or are there multiple variations?

That's where I was getting the signal and the tach worked but it was as if it was robbing or overloading the signal from the coil. I was hoping that I had it in the wrong spot and someone was going to tell me where to get the signal from. Not sure what you would be reading coming off the stator.....I thought that it would have to read the pulse from the ignition....

[MinnesotaTim]

The unrectified output from the stator should be close to a sine wave. Depending upon the instrument cluster that signal can be routed into it and the peaks of the waveform counted. On ATV's and snowmobiles from Polaris its typically 6 pulses per revolution. The key is that the instrument cluster must be designed to work with this signal. If the instrument cluster is looking for a true digital signal (0-5V square wave) or something else entirely, then this will not work. Does anyone have the specs on the instrument cluster you're working with???

- Tim

[jgordon]

The unrectified output from the stator should be close to a sine wave. Depending upon the instrument cluster that signal can be routed into it and the peaks of the waveform counted. On ATV's and snowmobiles from Polaris its typically 6 pulses per revolution. The key is that the instrument cluster must be designed to work with this signal. If the instrument cluster is looking for a true digital signal (0-5V square wave) or something else entirely, then this will not work. Does anyone have the specs on the instrument cluster you're working with???

- Tim

Tim has asked of anyone has the specs for the tach that I have. It is off of a 1990 GSXR 600.

I can tell you that it does read correctly when it is connected to the neg. connector from either one of the coils.

Thanks foir the reply Tim...