Now I think I may be having a problem. I get 12.5v at the battery when the bike is not running and 14.5v with it running. When the bike is sitting (at a light) the headlight is bright but if I touch the brake the headlight goes very dim and stays dim until I rev the bike at witch point it will stay bright again.

 

OK, George I found what you were looking for.

http://www.vlc.com.au/%7Ejustin/abou...g_replace.html

 

Thanks for the link - I'd found it before. Here's my "problem." The R/R on the bike looks nothing like this - or any other one I found in my search through this site. It has some small cooling fins - not a "flat" brick as shown here. It lines up exactly with the mounting holes in the frame and the wiring looks totally stock. The bike is essentially untouched before I got it - I am convinced it is the way it left the mothership. There is no wiring connector - just the wires entering a "potted" connection. There are 8 wires total, arranged in two rows. One has a white, yellow, yellow, yellow, black set. The other row of three is a red/white, black, and green.

I know the three yellow are the stator wires. The red/white appears to be +12 volts - essentially battery connection. I understand the "black" is the ground connection - but all the write ups ony mention one such wire. I am guessing that connecting both together and treating as a common ground is the way to go. The left over white and green are the unaccounted ones. And, just to add to the situation, only one connector near the R/R - the rest disappear in a main wiring harness run under the tank.

Looks like I am going to have to pull some pieces out of the way and start tracing.

I'll bring a camera home from work tomorrow and get some pictures.

Thanks for the input.

 

The plot sickens!

First - a caveat. I am NOT especially electrically knowledgeable, or even competent, so take this with however much salt you feel appropriate. And, I welcome any corrections or additional explanation from anyone more informed than I.

After much poking about, I found a wiring diagram for the '87's & '88's. The diagram and the accompanying sketch make it clear that these year machines have a different r/r and wiring connections. Turns out that two of the wires in question are the energizing wires for the field coil. According to the Honda Common Service manual, for 3 phase alternators with the powered field coil, the power to this circuit is controlled by a voltage sensing transistor that "pulses" the energizing of the field coil, controlling the magnetism of the field and thus at least partially regulating the charging current/voltage. I don't know if the later models work this way, but it does look like the Yamaha R1 regulator that is recommended so highly does NOT provide for control of this coil - making it, as far as I can see, inappropriate for these years - unless someone knows how to control the field coil. The common service manual implies - at least to me - that simply hot wiring the circuit to an ignition switched source will result in excessive voltage/amperage. I assume the regulator would try to deal with this, but deliberately overloading an already questionable component doesn't seem like a good idea.

As a result of this study, I had some definite tests to try to identify the potential cause of my problem, so I bailed from work a bit early today. I pulled off the tail plastics and went tracing the wiring to find all of the connectors. In the process I discovered the obvious connector near the r/r - NOT the one carrying the stator connections - was just barely making contact! Apparently it had vibrated/pulled apart to the point it was not making good contact. Wires and contacts looked good, so I added some dielectric grease and pushed it firmly together. I added a zip-tie to be sure it wouldn't come apart unintentionally again. Traced the wiring to the stator connection - it was solid, but pulled it and again, wires and plugs look fine. Greased this one also and put everything back together. fired up the bike - solid 14.5-15 volts!! Looks like I don't have a problem with the system - at least not at this point in time.

Here's a picture of the r/r installation, with the offending connector back in place, before I zip tied it. The fan was added maybe a year ago on a recommendation from this list.

Thanks to all who lent suggestions/advice.

 

Well done George , looks like problem solved

 

Some times it's the simple things...................
And the questions we don't like to ask............

Good result.
If you ever need an aftermarket R/R let me know - I run one designed for my 90 1000F, and they make them for the earlier model too. Has a big heat sink attached, and comes with a year's guarantee. Look up Electrex.uk
A new one from Honda has NO guarantee...............hmmmmmmmmmmm.