Voltage draw from Regulator

[jzmuda]

Hi,

I have an r-65 that is giving me charging/electrical issues. The bike has been ridden in very dirty conditions and stored outdoors most of its life. I have had a variety of charging/electrical gremlins so I won't go into all those details here. In an effort to exercise all electrical demons, I began carefully working through my wiring and checking each contact and applying dielectric grease. This is all good from a maintenance standpoint, but i know I there is something more significant that is wrong.

With the ignition switched off, when I disconnect the negative ground to the battery and measure between the disconnected ground wire and the negative terminal, I get a reading of around 2 volts. In order to determine the source of the draw, I began disconnecting various element of the wiring and found that when I disconnect the voltage regulator, the measured voltage between the ground wire and the battery drops to about .2 volts.

Is this typical behavior for a voltage regulator that has gone bad? Is there a way to check the voltage regulator off the bike? The bike is torn down right now and not in running condition so I can't do the typical diagnostics.

Are there any standard components (I don't have any clocks or anything) that always draw some voltage (even with the ignition off) from the system (i.e. I should never expect the voltage to actually read zero)?

Does someone know of a step by step electcial system refurbish procedure. I have seen lots of tid bits about verious components, but I'm looking more for an outline of things you would systematically go through on a new bike that you plan on taking on a long trip.

Thanks,

Jay

[uraldog]

sounds like you need to call Motorrad Elektrik and aks for a copy of classic boxer charging -- it's well a written easy to understand walk through of the beamer electrical system and trouble shooting guide -- once you get it and read it you wont have to rely on anyone but yourself and maybe Rick for parts --- BTW whens the last time you cleaned the heat sink and applied new grease to help heat transfer

[caponerd]

It's possible to get weird voltage readings between disconnected stuff. May not mean anything, but...

If you're using a digital VOM, try configuring it for current reading, then insert it between the wire you disconnected from the regulator and the terminal on the regulator that it connects to.
Any current draw with the ignition switched off indicates a problem.

Incidentally, if this is the case, your battery would be discharging every night. Is that happening?

Oh, one other thing, dielectric grease is just a means of sealing the connections from dirt and moisture. It won't fix a flakey connection.
You need to make sure that all the connections are clean and tight, and it's especially helpful to touch up the crimps on the connectors between the major components; alternator, rectifier, regulator, battery, with solder. I've seen a 1/2 volt gain (enough to make a difference between charging/not charging) in output by doing that.

[jzmuda]

Thanks for the feedback. I think I have narrowed the voltage drain down to the diode board. When I disconnect the connection between the starter and the diode board the draw goes away.

No, I'm not losing my charge overnight, but I do lose it slowly. Sometimes it is worse than others. I think I remember reading about the rubber isolators on the diode board wearing out and causing shorting. Maybe that is what I have going on.

I keep reading about this heat sink grease. Where does that go.

J

[jzmuda]

And the heat sink paste goes under the ingnition control module.

[caponerd]

The rubber insulators can be a problem. When I had to replace my rectifier, I put in new mounts.
Solid grounding of the diode board is also an issue. Mine has a heavy wire running to one of the starter motor bolts from the ground plane on the diode board.
I did this almost 10 years ago, and even though I'm running one of the "inferior" original equipment diode boards, it's been charging just fine ever since.
If I'd known at the time about the aftermarket boards, I might have put one in, but given how well mine's held up since getting it properly installed, I don't think it's necessary to buy one unless it happens to cost less than the factory part.

[caponerd]

Originally Posted by jzmuda

And the heat sink paste goes under the ingnition control module.

Use it sparingly. Heat sink compound is not a replacement for actual contact between the parts, but an improvement over air spaces between the parts.
Looking at any metal surface through a microscope will reveal jagged peaks and valleys. Heat sink compound is intended to fill the voids where the metal parts are unable to make solid contact, not to completely cover both surfaces.
Gobbing the stuff on will result in slightly worse heat transfer than if the two parts had been joined dry.

[jzmuda]

Thanks for the tips.

Anyone seen a write up on making your own diode board? It doesn't seem like it would be that difficult. . .

[jzmuda]

on a related note . . . to electrical anyway. Does anyone have a recomendation for electrical tape that doesn't leave behind a slimy residue after it has been installed for a while. The old cloth stuff seems better in that it just dries out, but I don't know if you can still get that stuff.

Jay

[jzmuda]

For completeness:

A nice write up on testing the Diode Board on a bench can be found here:
http://jhau.maliwi.de/mot/r-elec.html

A nice write up on testing the voltage regulator on a bench can be found here:
http://jhau.maliwi.de/mot/voltreg.html

Many thanks to the provider of these excellent resources.

J

[jzmuda]

On a side note. I hate electrical problem . . . so much that I relish the opportunity to diagnose a good mechanical problem. Nevertheless it seems that a majority of the problems I have are electrical.

What I am wondering is this: do the electrical geeks find themselves hopelessly working on mechanical problems just longing for an electron to step out of line?

[caponerd]

Originally Posted by jzmuda

Thanks for the tips.

Anyone seen a write up on making your own diode board? It doesn't seem like it would be that difficult. . .

I've designed, etched, and populated printed circuit boards before, and I'd say that it's not worth the effort for a $100 part. Others may disagree, but how often do we read about homemade diode boards here?
Unless you're really competent at electronic project construction, you'll never build one that's as good as those you can buy. Repairing an old one is a better option if you can find comparable diodes.

To answer your question regarding preference for mechanical vs electrical problems. I would rather deal mechanical problems if I have to deal with any at all.

[jzmuda]

So I bench tested the diode board and it is ok. This leads me to believe that the short must be somewhere down stream of the diode board . . . like in the stator.

One thing of note is that the three plug connector into the diode board has seen some heat (the rubber around the connector is slightly melted).

Do any of these things smell of a certain type of problem?

Thanks,

Jay

[caponerd]

Originally Posted by jzmuda

So I bench tested the diode board and it is ok. This leads me to believe that the short must be somewhere down stream of the diode board . . . like in the stator.

One thing of note is that the three plug connector into the diode board has seen some heat (the rubber around the connector is slightly melted).

Do any of these things smell of a certain type of problem?

Thanks,

Jay

SIgns of heat on a connector normally indicates a voltage drop at that location caused by a poor connection. (resistance)
Every bad connection between your alternator and your battery will have a negative impact on charging. If you have more than one bad connection in series, they add up. Doesn't take much to reduce the available voltage to the point where the battery won't charge. (seen it first hand)

It might still be worth your while to check for current flow through your battery with the ignition off. If you find any current at all (milliamps, even. but make sure the clock is unplugged), then you can start unhooking stuff until the current quits.