Question wiring stator to solid state reg/rec

D3viousd4n

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Hey everyone,

I’m in the process of swapping my 1978 XS650 from a PMA system back to a stock charging system with a solid state regulator/rectifier.

I have a quick question while I’m wiring the connection blocks. I have a black and white wire coming from the brushes on the stator that connect to the regulator via a green and brown wire. I don’t want to mix it up, how do I determine which wire connects to which brush?

I attached some photos. Happy to provide more info if needed. Thanks!!
 

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Last edited:
Welcome to the forum!!

Does your bike have the stock wiring harness?
I do not believe so. I’m at least the third owner, but I do know the previous owner had a lithium set up that blew up on him and fried the whole wiring harness. When I came to own the bike, I asked a mechanic to redo the harness and switch it back over to lead acid. All I can say is that the harness he used to replace it was found on eBay.

Got the brushes ready and about to install!
 
Got the brushes ready and about to install!
OK... if you have the newer brushes, they get wired like this one below. The top wire should reach the top inner screw (red circle).

Make note of the braided pigtail on the brush. It wraps around it's metal tab and there's a slot for it on the brush holder. The brush on the left in my pic is installed wrong. Do it like the one the arrow points to on the right.


1727464559808.png
 
Also, those nylon screws won't take a lot of torque before they strip. Be gentle with 'em.

Also also... can we inquire as to your mechanical skill level? Knowing that will help us help you.
Shoot. Realizing now I bought a pair for 70-79. I take it I won’t be able to use those?

Thanks for the photo that’s helpful. I’ve not got much experience. This is my first real bike and I’m trying to learn how to work on it myself. I’ve gained a basic sense of how the charging system works from this forum, YouTube, and reading the manual. I’m fine with some basic maintenance but suffice to say I’ve never swapped a charging system before and I’m happy to get any advice or tips I can from y’all.
 
Shoot. Realizing now I bought a pair for 70-79. I take it I won’t be able to use those?
No, you can use the older brushes. That stator is the old style that has had the nylon brush mod done to it. Just install the old style brushes like you normally would... the long terminal will just connect to the top left nylon screw.
 
No, you can use the older brushes. That stator is the old style that has had the nylon brush mod done to it. Just install the old style brushes like you normally would... the long terminal will just connect to the top left nylon screw.
How’s this look?
 

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How’s this look?
The one on the left looks correct, although it might not be completely sitting down in the holder. Give us an angled view of that?

The inner brush is not correct. the little brown plate is 90° off from where it should lie. And like I said before, the braided wire goes into a little slot cut for it in the holder.

1727467283500.png
 
The one on the left looks correct, although it might not be completely sitting down in the holder. Give us an angled view of that?

The inner brush is not correct. the little brown plate is 90° off from where it should lie. And like I said before, the braided wire goes into a little slot cut for it in the holder.

View attachment 336356
cool, fixed the inner brush and adjusted the outer brush
 

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Cool. MikesXS even supplied the wiring diagram for it.

View attachment 336352
Before I forget....

When you install the rotor, don't forget the woodruff key.... and smear a little grease in the tapered crank shaft for corrosion protection.

Couple questions here. Could you let me know if my understanding is correct?
So the stator has 6 wires:
3 yellow providing AC current
A black and a white connected to the brushes which create a current through the rotor
And a blue neutral with a splice in the middle that (I assume) goes to ground. If I’m correct this is here to discharge unnecessary electricity created by the alternator.

as for the connecting, my reg/rec has 7 wires
3 white which I’ll connect to 3 yellow.
A green and brown which I should connect to black and white (although which to which?)
And a black that I should connect to blue and ground out.
Lastly red goes to positive terminal on battery.

Does this all sound right? It’s different from the diagram from mikesXS. Instead I’m referencing this diagram attached.
 

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Couple questions here. Could you let me know if my understanding is correct?
So the stator has 6 wires:
3 yellow providing AC current
A black and a white connected to the brushes which create a current through the rotor
And a blue neutral with a splice in the middle that (I assume) goes to ground. If I’m correct this is here to discharge unnecessary electricity created by the alternator.

as for the connecting, my reg/rec has 7 wires
3 white which I’ll connect to 3 yellow.
A green and brown which I should connect to black and white (although which to which?)
And a black that I should connect to blue and ground out.
Lastly red goes to positive terminal on battery.

Does this all sound right? It’s different from the diagram from mikesXS. Instead I’m referencing this diagram attached.
3 yellow (or white) to 3 yellow (or white).... providing AC current

The top connector (nylon screw) is ground.... goes to the black wire at the reg/rec

The bottom connector is green. That's rotor power from the reg/rec
**I know the colors don't match the colors on your stator. Just make sure the reg/rec black wire goes to the top terminal and the green from the reg/rec goes to the bottom.**

The blue neutral goes to the neutral switch on the top of the tranny.

The yellow single wire goes to yellow on the bike. That feeds the starter safety relay.

Red to battery pos.
 
Since the combined reg/rec you got is made for the '70-'79 alternator and brushes, you really don't even need the nylon screw mod, you could use normal metal screws just like it was originally. But, the nylon screws will work fine, as long as you run the brush wire to ground.

No, don't follow that wiring diagram you just posted, it's for an '81 model and they have the brushes wired differently, basically opposite from how yours should be. On yours, the inner brush is grounded full time and the outer brush is fed regulated power on the green wire from the regulator. On the original set-up, the black wire running to the inner brush wasn't actually providing it with a ground, it was picking one up from it and sending it to the regulator. The inner brush was grounded on it's own through it's three mounting screws, directly to the stator housing. So, if you keep those nylon screws, be sure to run the inner brush wire to ground (along with connecting it to the reg/rec black wire). With the nylon screws isolating the inner brush from the housing, that black wire will be it's only grounding source.
 
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