Brown Wire from Rec/Reg Has Too Much Voltage

[Phill]

Over charging problem

Hi all. Hope everyone (in the USA) had a good Thanksgiving.

I've been finishing up my bike and while doing the wiring I found a problem. My apologies for this being long.

I have an 81 XS650SH verified by the numbers on the engine. It was running just fine before I made my changes. I added a box to store all the electronics and wires under the seat. While doing this I added some 6pin wire connectors to make it easy to pull everything out of the box for troubleshooting.

Following the simplified wiring diagrams on the site and also the manual for my bike I connect the brown wire from the Rec/Reg to the "fuse block" (coil, ignitor, ...). This is also connected to the ON side of the power switch (to power the alt/stator).

The problem is that I get too much voltage and it blows out lights and stuff. I revved up the engine and I get 20-30v coming out. If I take the brown wire out of the fuse box loop then everything works fine, but I don't know if it's charging. From what I read, it's used for charging the battery.

From under the engine I have the three whites, a brown, and a green. The yellow seems to be capped off somewhere under the black tape. I am kick only. In the manual the green goes to the pickup/brush (the little square thing) and then it should go to ground (black). In the simplified diagrams it shows a brown coming back to the rec/reg. This is strange that it's different.

I've been doing a bunch of research and searching the site for answers but I haven't found anything yet. Been working on this for a week now. It's also strange that I blew out my headlight even though I have an inline fuse before the headlight.

 

[pamcopete]

phil,

There is no regulation without the ground wire connected to the frame. If you have mounted the regulator on the battery box and relied on it for a ground, surprise! The battery box is not grounded. It floats on its rubber mounts.

 

[Phill]

I have a bolt welded to the frame that holds the box. I'm grounded to that bolt. I'll check to make sure it's grounded good, but I think it is because the light on my power switch works fine. My battery is also grounded to the frame.

What you said does make sense though.

 

[XSLeo]

On the 81 the brown wire supplies battery voltage to the Brown wire brush and to the reg/rec.
Power flows on the brown wire to the brush, from the brush through the rotor, out the brush on the green wire. The green wire goes to the reg/rec. At the reg/rec the reg parts uses the battery voltage to determine if the battery is low. If low the reg turns on the transister on and grounds the green wire and current flows through the rotor. This current magnetizes the rotor. As the rotor spins it excites the stator to make AC electricity. This AC electricity is sent on the three white wires to the rec part of the reg/rec where the AC gets rectified into DC electricity and sent to charge the battery.
Ok just reread your post. You are sending battery voltage to the brush on the brown wire, the other brush wire is should be green and should not go to ground, but to the reg/rec. With battery voltage flowing to the brushes then to ground then you have Hotwired the alternator so it puts out max voltage.
You need to hook the green wire from the brush to the reg/rec green wire.
Leo

 

[Phill]

Thanks for the reply XSLeo.

I was saying in my original post that the green from the rec/reg goes to the brush (green), then from the brush it should go to ground according to the manual, but in the simplified diagrams it goes from the brush over a brown wire back to the brown on the rec/reg. I do not have the green going to ground.

Here is the diagram that I'm using:

When I hook it up this way I get too much voltage.

In the Clymer manual it shows the brown wire from the brush going to ground and not back to brown on the rec/reg.

 

[Phill]

Ah, I think I figured out that in my Clymer manual the little box is not the brush but actually the neutral switch. That's making more sense now.

 

[XSLeo]

In the diagram you posted the little box that a brown and grren wire go to are the brushes.
In your diagram the brown wire after the switch comes down and splits to go to the reg/rec and the brushes. The green wire from the brush goes back to the reg/rec.
Also you see a black wire coming from the reg/rec to ground. It shows a wire from the alternator to ground. This is just the diagrams way of showing the alternator is grounded, there is not really a wire. The stator grounds physically by mounting to the engine and the engine to the bike.
Actually the black line from the alternator to ground can be removed from the diagram.
That diagram is correct for your set up.
There are a few changes I might make. After the key the brown wire splits and goes up and tee's to the lighting fuse, ok. Where it goes over to the brake light, I would put the fuse before the switch. That way if the switch shorts to ground the fuse will blow. The way it is, it will blow the main fuse instead.
Back where the brown wire goes down to the reg/rec and brushes I would put a fuse there to.
Thats just me. It will work just fine the way it is.
Leo

 

[Phill]

Thanks for your info. I will recheck all the wiring again. It sounds like it's correct, but I get way too much voltage on the brown wire in the diagram above. The hotwire situation might be happening somewhere. I'll have to open up the left side and trace all the wires. It was running great before I messed with it. lol. Thought I reconnected everything to the same places, but I guess not. I understand the diagram and how things work, just don't know why I'm getting what I'm getting. Has to be something simple.

 

[XSLeo]

In your Clymer book thats one of the mistakes in there. The G, SG, H & SH are shown wrong. Yours is like the SJ. Well as far as the alternator goes.
If you look at the SJ diagram it doesn't show the brushes seperate from the altenator. The brown wire just goes in on the left and the green comes out on the right, those are the brush wires.
Leo

 

[Phill]

Ah, I was thinking about that too. I looked at the other diagrams and it made more sense, so I checked the engine code again to make sure I had the right thing.

If it's a mistake, then I feel much better now. Thanks!

 

[Phill]

I've pulled every wire and made sure they are all correct and soldered for maximum connectivity. I verified every ground for the charging and ignition system. I have everything else disconnected.

Still charging too high. I'm thinking that my Reg/Rec is bad at this point. I tested the diodes and they seem fine, but no way to test further.

One question that I have is the brushes do not have the nylon screws. Should they be for the 81 XS650SH? I have green and brown going to the reg with power on brown. I'm thinking that it's grounding and giving full power. But I doubt it's the problem because when I got it, it was running fine for weeks before I cut wires. I wish I paid more attention when I did.

I'm going to see about getting a new Reg/Rec and see if that's the prob.

 

[xjwmx]

You don't need the nylon screws using an '81 regrec with an '81 stator. Another thing you could check is to see if the green wire is accidentally grounded somehow. If it is the voltage will go way high. Worth a shot anyway.

 

[XSLeo]

With your high charge if the reg/rec is ok then the brown wire voltage is to low or the green wire is shorting to ground.
If you have a spare reg/rec, try it. I might check for voltage at the brown wire at the reg/rec and the brushes. If it reads less than .2 or .3 less than battery voltage you have a problem some where between the battery and the brown wire. Usually in the key switch.
Leo

 

[Phill]

Spent the whole weekend testing all the wires. Tracing them down and making sure they are not grounding anywhere. I took the switch out to make sure it was not causing a problem (but it's the same switch from before). I took everything out that wasn't needed for the motor to run. I keep thinking that it's the green wire, but I just can't find the problem. I replaced all the wire from the battery to the reg/rec & ign to the covered wires
under the bike.

I'm thinking that when I tested the first time and blew out my headlight, I might have blew out the reg/rec too. It was getting up to 60 volts when I tested just after that. I had no idea it would do that (this is my first bike). I'm at a lost why it didn't blow the fuses. they are 10amp inline fuses in front of the lights. I have a 20amp fuse on the red going to the battery. Strange.

I just bought the Reg/Rec advertised in the classifieds here. Should have it in a day or so to test with. If that doesn't work them I'm pulling all the wires and rewiring the whole bike. ;-)

On the good side, I know the wiring for the bike now. It's funny... I thought I was going to have problems setting up my carb, but it runs like a champ first time. Swapped a BS34 on with 145/50 jets, pods, straight baffled pipes. I have the 17/30 sprockets on it and I can peel-out of my driveway.

 

[Phill]

Got it!

I put the new Reg/Rec on and it did the same thing. So I pulled out every bit of wire and re-wired the whole bike. Now it's running perfect and not charging over 14.5 no matter how much I rev it.

I'm thinking that somewhere down under the engine it was shorting out and it was a coincidence that it started after I moved the wiring into my new electronics box. But now it's all new wiring and all wired correctly.

While I was redoing it I put in a fuse block with bus fuses and made everything nice. I still have some wiring to do, but I'll be finished with it tomorrow.

Thanks again to everyone that posted help.