After blowing another headlight (and all instrument bulbs) on my 1974 DT360A, I've decided to install the voltage regulator from Rex's Speedshop. I have a fresh battery, new 4020 sealed beam and new instrument bulbs installed and want to add the regulator before starting up the bike.

I've reviewed the Service Bulletin and it says to mount the regulator on the outside of the headlight shell and ground using 18 gauge wire. I'm not quite sure where to mount the regulator and how to route the wiring. Does anyone have pictures of an installed regulator they can share?

Regulator: www.rexs-speedshop.com/epages/es143131.m...ewAction=ViewProduct

Much thanks.

The regulator can be mounted most anywhere on the frame. If you can get it exposed to some air flow it does get warm and that helps. Best not to route other wired directly over it. Follow the instructions for connecting in the bulliten, and then find a place you want to mount the regulator, then simply route the new wire along any existing cable.

Thank you Makato. The Bulletin says to mount the regulator to the exterior of the headlight shroud. Do I then run the yellow wire through the back of the shroud seen in the picture below?

That should work. You may need to extend the wire on the regulator - I don't recall how long Rex provides.

Saw a couple hits about voltage regulator installs.

I picked this one since mines a 75 instead of making a new thread.

I drilled two holes in the bucket with no remorse since its so rusty anyways. Thought about mounting somewhere else but this seems ok.

.... what do i do with this yellow wire? I thought we were going to be lucky and thered be a female end for the yellow wire.


So whats the best way to splice it into the dark blue wire?

... the dark blue wire i see has two wires going to tab connectors.

And one going into the big white connector.

I dont want to jack this up right at the end!

Picture please...

I guess that would help huh. Lol.

Ran back inside to grab a donut and look up diagrams. Attached photos of what I am gooning with.

I can't remember looking at the wires... sorry... I just don't remember the blue in a plastic connector.

The blue you are looking for should be coming into the headlight bucket from the light switch mounted on the left handlebar and then should connect to blue wires going to the instrument illumination lights... one in the tach and one in the speedo.

(There is a light blue wire that runs the oil light... that is NOT the one you want... )

I found a NOS switch on ebay... as I remember it the wires to the gauge lights plug into the the dual bullet connector circled...

Looking at the wiring diagram... it looks like the blue in the plastic connector goes to one of looms that go back down the frame of the bike? That's the taillight wire.... runs on DC. Don't connect the regulator there.