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Discussion Starter · #1 · (Edited)
Hey all. I’m in the midst of re-wiring my ‘73 CB450 with an M-Unit at the center. I replaced the stock regulator and rectifier with a combo unit from Ricks but the wiring is confusing me.

The instructions state that the three wires from the stator go to the three yellow wires from the reg/rec, the black to battery negative, and the red to positive. Green/red goes to the idiot lights for the neutral light. From what I understand, when using the M-Unit, the black need to see +12v from the lock input, is that correct? If so, how does the unit ground? Any help would be appreciated.
 

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Sensei
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Very Simple.... The Black from the "Rick's" unit IS the ground ... Paint or otherwise "tag" it green...Connect directly and only to battery negative.....

ALL the small gauge Honda BLACK wires in the main harness are "switched" battery power and are battery positive when your key switch is turned to "on".......
The Honda RED wires are non-switched battery positive.... (ALWAYS "HOT").....
ALL the Honda DARK GREEN wires are Grounds (battery negative)....

Why anyone would add an unneeded, expensive unit that just complicates the simple Honda wiring is beyond me......
EVERY additional connection made simply becomes an extra possible failure point......
Everything worked as it was...Why reinvent the wheel?....
I understand upgrading individual existing components, but that is a different matter entirely......
JMHO
 

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You might have the wrong reg-rectifier. Later Hondas have three phase alternators with three yellow wires. Please post a link to the R-R you bought.

On the alternator side of the harness, there are a yellow (Daytime), pink (night time) and light green with red stripe (or brown if it is an older stator) common. On bikes fitted with an off position for the head light, the yellow and pink run through the headlight switch. This is a permanent magnet alternator with a fixed output. the lower output is when the headlight is turned off and the higher output is when the headlight is on. When the headlights are turned on, the yellow and pink are connected together. Some people connect these together at the alternator to give the high output all the time. This is how the bikes with the 'always on' headlights are wired. It is ok as long as you always ride with the headlight on. I didn't do it to my K5. If these are connected together and the headlight is off then the battery will be overcharged and boil off the electrolyte.

The brown with red does not come from the alternator, it grounds the neutral light when the transmission is in neutral.

Just remove the old regulator. Be sure to properly cap and stow the bike side wires. The yellow is hot to the alternator AC output and the black is hot to the +12v when the engine is running. You don't want these to ground out.

The stock rectifier has a Green (ground) Yellow (daytime) pink (night) and red with white stripe (battery). You can use the green (black on Rick's reg-rec) and Red with white stripe (red on R-R). This is the output side of the reg-rec. The yellow wires are the input side of the reg-rec.

I just went on Rick's website and looked at the stators they list for the CB450 DOHC. I see why this is confusing. They don't look right to me, but you can try to hook the Yellow-Pink and Lt Green/Red stripe to the yellow wires on the rec-reg.

Regulators for the newer 3 phase alternators are a bridge containing six diodes. Regulators for our honda twins have a bridge containing four diodes. A three phase rectifier can be used on a single phase circuit by not connecting to two of the diodes, only using four diodes. The stock Honda rectifier and two wires the input power to the rectifier bridge, they are the yellow and lt. green with red stripe. The outside of the stock rectifier outputs to the green (ground) and red with white stripe (battery positive). It does matter which wires go where on the rectifier.

I have the Oregon Motorcycle parts Reg Rec on my K5. The only complaint is it is big and it was hard to find a place to mount it. Their FAQ page describes what I was saying in more detail>
 

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Sensei
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Jim.
Hate to correct you, but your last post contains many errors.....

The Green with Red stripe wire is the neutral light switch connection...IT MUST NEVER be connected to the Regulator or Rectifier!!!

The older models (Pre 1969) have Pink, Yellow, and Brown wires to the stator....Later models Have Pink, Yellow,and White wires......

On the old models, the Yellow and Brown are the "daytime" AC output, with the Pink ADDED to the Yellow AC side for higher "nighttime" usage.....

On the newer ones, the Yellow and Pink are the daytime AC output, with White added to the Yellow side for nighttime usage......

As to connecting to the Ricks 3-phase unit, the Pink, Yellow, and White stator wires simply connect to the Yellow R/R wires, Yellow to one, Pink to another, and White to the third....
It DOES NOT matter which to which......

I DO AGREE that using a three-phase unit on Single-Phase output is a waste of both money and mounting space, but it will function correctly if properly connected.....
 

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Discussion Starter · #5 ·

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Wow, that one is pricey. I knew they sold them but didn't know how much they were. Could have had the Sparck Moto unit for a third that price
 

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Discussion Starter · #7 ·
Yes, it is pricey. I am still not convinced that I have the right unit either. As far as I can tell, there needs to be a +12V sensing wire running from the M-Unit and a ground - though I'm not sure what is what on the Ricks unit. I may just have to pick up the Sparck unit because the wiring makes a lot more sense there. If anyone does have experience wiring a Reg/Rec combo with an M-Unit please let me know. Like I said, all the wiring in the bike is brand new.
 

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Rick's sells their three phase unit for use on all the Honda twins (even our single phase 350s and 360s) and this is part of the confusion.

Each of their white wires goes to the yellow, pink, and white wires coming directly from the stator (doesn't matter which goes to which).

The black wire on the Rick's unit gets grounded and the red wire should go directly to one of the following places (no preference on location, just select the nearest option that works for your build):
*Main power connection for the M-Unit
*Hot side of the solenoid (if you're using one)
*Battery positive terminal

The voltage sensing on the Rick's unit is handled internally, so there is no direct connection to the M-Unit like there would be for the Sparck unit.
 

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Discussion Starter · #9 ·
Rick's sells their three phase unit for use on all the Honda twins (even our single phase 350s and 360s) and this is part of the confusion.

Each of their white wires goes to the yellow, pink, and white wires coming directly from the stator (doesn't matter which goes to which).

The black wire on the Rick's unit gets grounded and the red wire should go directly to one of the following places (no preference on location, just select the nearest option that works for your build):
*Main power connection for the M-Unit
*Hot side of the solenoid (if you're using one)
*Battery positive terminal

The voltage sensing on the Rick's unit is handled internally, so there is no direct connection to the M-Unit like there would be for the Sparck unit.
Thanks a bunch. This makes a lot more sense now!
 

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Sonreir also makes the SparckMoto units, so I would assume that Rick's is essentially his competition. The fact that he still chimed in here with an experts opinion really speaks to his character. Hats off to you!
 

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^^^which is the very reason I suggest Sonreir's stuff, he's good like that and I've seen many, many times he's helped posters
 

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Agreed. I used his R/R combo unit and the plug and play aspect was huge for me. He inquired about the make/model to ensure he put the correct wiring harness on, which made installing very easy.
 
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