cb125 12v conversion help

[rupaulpierce]

I have it *working*, but i don't think i've tied up all the loose ends. Lots of information out there, but I want to nail it all down and publish a more comprehensive DIY when I'm done.

I have a '74 cb125S1. My stator is from a cb350. Reg/rec from a cm400.

Diagrams available here: http://oldmanhonda.com/MC/WiringDiagrams/MCwiring.php#class

The regulator has six wires:

-black - voltage sensing
- green - ground
- red/white - +12v
-three yellow inputs

The stator from the cb350 is similar to the original. Three wires, plus red/green neutral indicator to the same plug.
-white (to headlight switch)
-yellow (to rectifier)
-pink (to rectifier)

Among other things, I've read to splice the white and yellow together and connect this, along with the pink wire to two different yellow inputs on the regulator. If this is done, a disconnected white wire in the harness coming from the headlight switch is left over. Is this the correct wiring?

 

[rupaulpierce]

I connected the yellow and pink wires to the harness, and then to the regulator in place of the old rectifier, using two of the yellow inputs. The third yellow input I jumped to the white wire coming from the stator. 13.9v at idle.


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[trek97]

This contains a link to the exact schematic you need. I think he used the cm400 R/R also.
http://www.dotheton.com/forum/index.php?topic=65898.msg771259#msg771259

 

[rupaulpierce]

That's where I got the idea 8), but he doesn't answer this question. No matter, answered it myself I think. I also haven't found any difference connecting the black wire (voltage sensing) or not.

 

[Sonreir]

Black wire definitely needs to be connected.

White, pink, and yellow from the stator all go to one of the yellow wires on the R/R you're using.

 

[rupaulpierce]

why? no difference registering on multimeter

 

[rupaulpierce]

Black wire definitely needs to be connected.

White, pink, and yellow from the stator all go to one of the yellow wires on the R/R you're using.

and to clarify, pink and yellow run through the harness. white is wired directly, leaving the white white from the headlight switch disconnected, right?

 

[Sonreir]

and to clarify, pink and yellow run through the harness. white is wired directly, leaving the white white from the headlight switch disconnected, right?

Correct, more or less.

The yellow can be run directly from the alternator as well.

In the stock setup, the yellow is run to the headlight switch, regulator, and rectifier. Voltage is regulated in the stock setup by shunting power from the yellow wire to ground and you get increased charging when the white connects with the yellow when the headlight is on.

 

[rupaulpierce]

so what would the black wire do that it isn't doing on my bike now?

also,
from reading the "un-scooter" thread, i also suspect i need a relay to make my kill switch work. it's an all in one from DCC, it's a pushbotton rather than the stock selector switch.

 

[Sonreir]

The black wire detects the voltage and permits the regulator to be more effective. The battery, to an extent, will help regulate voltage, but that's not what it's there for.

And yeah... push button kill switch on a Kettering ignition or TCI ignition will require a relay.