I copied Mauser and used one of the horn mount bolts on my RT2 and DT3. I did have to fit an extension to the wire, so that it reached the connections in the headlight shell.

That is the one I bought. Does it work well? Did you have to make a bracket to mount to the horn and did you connect it to the blue headlight wires?

That looks like the one I mounted yesterday..From Brain Tarp.. I bolted to the bottom, outside of the headlight bucket... The yellow wire was positioned so it was located right at opening for wires... I did stand it off so as not to touch the gizmo to the bucket... You really can't see it..
Sneezles61

Photos of mine attached in this order - DT3, RT2 and DT360A.

As you can see, the only one that I made a bracket for was the DT360A (which I might bend a little, just so that it aligns with the forks).

I'll need to check that the regulators are getting an earth from the frame. If they aren't, I'll make some new earth wires up.

Extra length of wire attached to the single yellow on the voltage regulator, and this attached to the blue in the headlight bucket.

As it happens, to save splicing the blues, I used some spare three port female connectors, with a very short link between the original double female and the triple (see last photo).

   

 

 

I keep my eyes out for used original Yamaha regulators on ebay.  I've never paid over $20 shipped and, knock wood, never received a bad one.  Early 80's models got much smaller but work just as good.

The main reason I buy used Yamaha is many new aftermarket look a likes simply don't work. I had a new one not work years ago and then found out DEET had done extensive research and testing and had not found any of the aftermarket look a like regulators to work like the Yamaha one does.  He posted a video here someplace. 

Not to say every one of the aftermarket units have been tested and all don't work but many have been and none of the ones tested were found to work.

DEET has found a scooter regulator... made in Italy I think... that can be had new for a reasonable price...  three wire hookup...  might even be better than the Yamaha unit.  That's what I would buy if I wanted to go new.  DEET has them for sale or used to sell them.

P.S.  Original headlights are not cheap...  if you can find one.

 


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 This is where I mounted mine.....minor modification (enlarging) of one bolt hole.

Theres mine...under the bucket
Sneezles61

Here's the one on my CT1-C, not sure if the larger ones will fit in this position.