Author Topic: 7 wire Rectifier/Regulator wiring help.  (Read 4401 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 calj737

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Re: 7 wire Rectifier/Regulator wiring help.
« Reply #1 on: September 14, 2019, 06:58:02 AM »
Logically that would work. But I am not about to tell you with any guarantee how to hook it up. Damage to components is very possible with the incorrect Reg/Rec.

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.

If that proves true, turn off the bike.
Attach the Green wire to battery NEG.
Jumper the Brown to any Black wire on your original harness.

Start the bike, 5,000rpms, measure the voltage at the battery. It should NOT exceed 14v. If it does then either the wires are wrong or the unit is the incorrect type. Stop the motor. Disconnect the unit, then buy a unit specifically for your bike model.
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"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline scottly

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Re: 7 wire Rectifier/Regulator wiring help.
« Reply #2 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.   
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Offline calj737

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Re: 7 wire Rectifier/Regulator wiring help.
« Reply #3 on: September 15, 2019, 05:22:19 AM »
My expectation is the Red in the connector is field coil.  ;)
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
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"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline scottly

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Re: 7 wire Rectifier/Regulator wiring help.
« Reply #4 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....