electronic tach help

i bought some ZRX gauges for my KZ. they were cheap since they had no needles. Also,they have fiberglass patchwork so they must have been in a crash, but they were supposed to be in working order. Not so sure about that now.
so i got some needles, made up some brackets, mounted, and wired them up. then i started the bike and the tach needle doesn’t move.
i have a Dyna 2000 and it has 2 tach leads.. i tried both and neither worked.
my question is, is there another wiring method i should try before i give up on them? i have ordered another set, anyways, but then thought , i should ask the pros.

i just heard that i may need a resistor installed?? does this make any sence ??

I'm pretty sure the resister is to bypass the anti-theft in the ignition switch on a ZRX.

Checked the ZRX wiring diagram to see how the tach is wired?



I'm putting a 05 ZX10 dash on a KZ750 twin, and a 01 ZX12 dash on the 96 ZX11, so I kind of have an idea of what you're dealing with.

yes i did check the wiring befor i started. the tach lead goes back to the IC Igniter.

I think the tach is expecting a square wave pulse from the ignitor, if the Dyna is outputting a square wave pulse and the tach is not working, then the tach must be bad.

Makes sense to me anyway.

Where you at Lou?

Here, but I don't really have much to add to what you said. I don't have much experience with factory tachs. My gut feeling is to suspect the Zrx tach is bad as well. As you said, it's generally going to expect a square pulse.

well u guys r way ahead of me. i dont even know what a square pulse is. last i heard , i was trying to put a square peg in a round hole. :woohoo:
whats a square pules?

I have ordered another tach, and gotten a reply from Dyan tech. They said to try running the tack from my coils negative lead.
I have put my old gauges back on for now. I have 3 track bikes to prep, so not much time for the kz. When the new gauges show up, I’ll try the coil lead and retry the dyna leads. Then I will either be happy or sad.
Thanks for the replys back at ya soon.

The signal that the tach uses is a DC signal which changes from roughly 0 to 12v everytime a coil fires. It's the standard pulse that most tachs use from that era.

The way to get that signal, on most tachs from that era, is to connect the tach wire to the negative wire on the coil. That is the wire that goes from the coil to the igniter. On a normal KZ, that wire is black for the 1-4 coil, or green for the 2-3 coil.

The see a square wave,an Oscilloscope is needed. It displays the waveform on a CRT(Cathode Ray Tube) much like a TV screen. It can also be used for troubleshooting, probing components for proper operation.

Well that makes it perfectly clear. :blink: i am now qualified to be an electonics scientist. :S

i think i had better stick to beer analysis :woohoo: .
Thanks

Mark, if you truly want to test this out...

A simple 555 timer design (~ 16.6 pulse per second = 1Krpm) should be able test this out for you...
With potentiometer , leave user adjustment for 1K -> 10Krpm...
Basically you're building a Frequency pulse generator versus square wave (50/50 duty cycle)...

You'll need a 12Vdc power supply as well, wall transformer will be sufficient.

Do you have the wiring diagram for this unit...?

If interested to try, e-mail me the wiring diagram you have and I'll draw you up a simple circuit for parts readily available at Radio Shack...

Dave

Thanks Dave. That would be great.
i may take u upon this, but let me try the simple route first.when the new gauges come in i'll give it another go. if they fail then i'll give u a buzz.