Thursday, May 21, 2009

wiring tacho

Well at some point I'm gonna want to wire in this nice tach I have. It will also function as my speedo/odo. For now, lots of brushing up on motorcycle electrical stuff. My wiring harness has seen better days and all the reading I've done indicates I'd be well served to do it all up proper with MIL spec wire and sealed connectors. All, and I mean ALL the connectors had little spider nests and spider poop. But somehow, it ran before I began this epic process, so let's see If I can get it limping along with the dusty old stuff first.

Anyway, let's roll out some diagrams. Here's the bike's wiring I copied from a Clymer Manual:

The SPA tach that I have came with a few directions; I found their manual PDF on line and show the schematics contained therein below. Since my bike had no tach originally, I guess this means I am left to wire the new one into the ignition coil:

This is just a table of the various connections to the meter's body. SPA provides a wiring harness that plugs into the 10 prong port atop; the shiftlights are left as an exercise for the user who wants to dragrace

The tach also comes with a speedo pickup. I'll run the sensor wire for this thing along the hydraulic line for the front disc brake, I think:


  1. Aw c'mon. Spider poop? I've never heard of that before. That's not going to stop you from having a running bike. And the tach should connect in to one or two wires on the bike, what's with trying to get to know the whole thing?

  2. Hey man, this bike was a spider haven before I got would not believe the places I found dessicated nests, and yea, the little arachnids gotta crank a dode, each one of them.

    Anyway I'm just putting these schematics up for now,not planning on letting them get in the way of starting the bike, which UPS seems to be doing a grand job of anyway...

  3. Hey, what SPA instrument did you use please? Looking for something for my DR build.

  4. I'm using one rated from 0-9000RPM with a speedo function. I believe it's on their website here: