Regulator wiring with Motogadget M-unit

b5iveS4

Been Around the Block
I'm finishing up the wiring on my '77 XS360 and the last thing I'm stuck on is wiring up the 2 regulator wires. I have a new 7 wire rectifier/regulator combo. The rectifier wiring is fine, 3 whites from the stator, red to power and black to ground.
The issue I'm having is the wiring on the 2 regulator wires. The green from the harness goes to green(I assume) and then theres a brown wire.
On the stock harness, the brown wire only appears at the plug to the regulator and from the regulator, it branches off throughout the harness connecting to various circuits, mostly turn signals, brake switch and horn, etc.

Does anyone have any experience with this? I'm wondering if I can just run brown from the regulator to a random circuit in the m/unit or maybe to the AUX port? Doesn't it just need to keep an eye on voltage so that it can compensate for a loss or spike in voltage? If this is super confusing, I'll try to clear it up. I have wiring diagrams as well as photos of the actual harness if needed. Thanks!
 
The brown and green power the field coil , the combo unit identifies low voltage limit and energizes the coil to begin alternator output. The reg then cuts field coil power to cease charging when charge is attained. make sense?

It is easy to understand on my simplified diagram here: http://www.dotheton.com/forum/index.php?topic=62814.msg715964#msg715964
 
Still confused haha. I really appreciate your help and I'm excited it's on the same bike too! The only thing is that on the Motogadget M-unit, each circuit is individual...so from your diagram, it looks like I'd tie brown into the + wire on the coils. Super confused. I've even talked to revival cycles in Austin since they use them so much and they're not really sure either. Just told me to test wires until it works. Solid advice I suppose haha
 
I need to raise this question from the dead.. having a haunting issue with overcharging when hooking up the regulator to the m-gadget unit. Like it cant read and regulate the current and constantly powers the field coil!
 
datadavid said:
I need to raise this question from the dead.. having a haunting issue with overcharging when hooking up the regulator to the m-gadget unit. Like it cant read and regulate the current and constantly powers the field coil!

Make, model, and year?
 
Sonreir™ said:
Make, model, and year?
Xs750, all are the same principle charging system so no difference between the years, except late models had combined r/r unit.
I believe i solved my own problem last night though - previously i powered the field coil through the aux outlet on the m-unit.
Now i hooked it in on the ignition switch, so it got a true signal straight from the battery, unmodulated by the m-unit. Also + and - was switched on the field coil. When the current took the right way around i got correct and stable readings of 14.2 all through the rev range.
 
Alternator should have six wires. Three white wires in a four pin plug, then a black, a black/red, and a green in a three pin plug.

The white wires all run directly to the regulator/rectifier. For the other plug, the black/red is your oil pressure wire, the black wire gets grounded, and the green wire should go to the green wire from your regulator/rectifier (this is the field coil power wire).

Your regulator/rectifier will have two plugs as well (later models sometimes had a single eight-pin plug, but all the wire colors should be the same, so bear with me). The six pin plug will have three whites, a red, and a black. The white wires from the plug go to the plug on your alternator with the white wires. The red goes directly to your battery positive terminal and the black gets grounded. The three pin plug will have green, brown, and black. Green should run directly to your alternator and match up with the green wire there. The black gets grounded and the brown should connect into the AUX port on the m-unit.

That match up with what you're seeing?
 
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