Author Topic: 7 wire Rectifier/Regulator wiring help.  (Read 4694 times)

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Offline Mahoo

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7 wire Rectifier/Regulator wiring help.
« on: September 14, 2019, 04:11:26 AM »
Hey All,

I have a 77 CB550 that I am rebuilding/cafe-ing and with the help of this forum I have been able to get most of the work done.

My issue the regulator/rectifier that came with the bike from the po is a 7 wire. The 5 wires in the block are 3 white, a black and a red. The two loose wires are green and brown.

I am not even sure if this is the write r/r for the bike or not. Sorry don't know the brand or model, otherwise I'm sure the vast internet could have helped me.

Can someone please help me with the wiring.

Thanks in advance.

Sent from my LM-G710 using Tapatalk

1977 CB550K - about to be stripped...

Offline scottly

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Re: 7 wire Rectifier/Regulator wiring help.
« Reply #1 on: September 14, 2019, 11:16:10 PM »

If you were to attempt to diagnose/test it, I'd do so with all other functional elements disabled on the bike and hook that to a battery and the stator in this way:

3 Whites to any of the 3 Yellows coming from stator.
The Black to battery NEG.
the Red to battery POS.

That will permit you to start the motor then examine the voltage at the battery which should be well above 14v with the motor running at 3,000RPMS.


Without a connection to the field coil, or a connection from switched 12v to the regulator portion, the charging system will not function, and the voltage will not rise to 14v.
Mahoo, the regulator you have *may* be compatible with the CB system, but since it doesn't use the standard Honda color codes, it's hard to say. Are you using the stock wiring harness?
PS As this question is not related to M-unit, M-button, M-gadget, M-relay etc, it should be moved to the main bikes forum.   
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....

Offline scottly

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Re: 7 wire Rectifier/Regulator wiring help.
« Reply #2 on: September 15, 2019, 06:46:21 PM »
The 5 wires in the block connector are for the stator and rectifier. The loose wires are for the regulator and field. One of them would connect to the stock harness black wire (switched 12V) and one would connect to the stock harness white field wire. Which one is which is anyone's guess.
Don't fix it if it ain't broke!
Helmets save brains. Always wear one and ride like everyone is trying to kill you....