Regulator/rectifier cb500 -73

[Festman]

Hello!

I bought at new R/R on ebay for my cb500. I wanted a smaller one compared to the original. I picked it up today and noticed that it only has five wires coming out of it. Three yellow, one green, one red. The problem is that I also have a white cable coming from the engine. And that cable doesn´t have anyone to play with if I connect this new R/R.
Do I have to buy another one or can I fix it in any way?
They are incredible cheap but now that I have one I would like to use it.

/Fredrik

 

[Sonreir]

The R/R you have is for a CB400T / CM400. It's for a three phase permanent magnet and you need one for a three phase electromagnet.

It's not going to work. I can tell you how to jury rig it, but you have a chance of burning out the R/R if it's not rated for the amps that your alternator can put out.

 

[Festman]

Thanks for the reply!

Aha, ok crap. I guess I have to buy a new one.

Jury rigging sounds interresting. This R/R is right now useless to me so as long as nothing else get damaged from the jury rigging... Please let me know how to do it

/Fredrik

 

[frogman]

I bought one of these for my 550, might work for you, works fine on my bike.

http://www.ebay.com/itm/Regulator-Rectifier-Fits-Honda-Motorcycle-CB550-CB-550cc-F-K3-1975-1978-/290644872204?pt=Motorcycles_Parts_Accessories&hash=item43abc8cc0c&vxp=mtr

Send the other one back or sell it.

 

[Sonreir]

OK... so I can't guarantee no damage, but the thing most likely to be damage would be the R/R (which you'd have to replace anyway).

Going into the alternator connector should be three yellow wires, a white wire, a green wire, a blue/red wire, and a green/red wire.

Disconnect the alternator plug from the harness and measure the resistance between the green wire on the harness side and the negative terminal of the battery. Hopefully you'll have less than an Ohm.

Plug everything back together and find the white wire with a female spade on it. It's likely to be grouped with a black wire and a green wire, also both with female spade connectors. This white wire will need the female spade connector removed and it should then be spliced into the black wire with the female spade connector. The white wire is for the exciter on the electromagnet in your alternator and the black wire is what normally provides power to your regulator. What we're doing is essentially bypassing the regulator and running the electromagnet in your alternator at full power, 100% of the time. In a stock setup, this would be bad news, but the new R/R you have is shunt type, so it regulates voltage by pushing the excess to ground instead of varying the electromagnet like a stock regulator would. Anyway, the three yellow wires on the R/R should match up with the three yellow wires coming from the alternator.

After it's all wired up, you should definitely check voltages are different engine RPMs and make sure voltage rises appropriately when you rev it, but doesn't go over 14.5V or so.

 

[Festman]

Thanks! That is really great information!
I will try this in a day or two if get the time. Or mayby I´ll buy another one. I dont want to mess up the alternator.

Now I happened to stumble over this one on aliexpress: http://www.aliexpress.com/item/6-Line-Voltage-Regulator-Rectifier-For-CF-CH125-150-250-Suzuki-Scooter-ATV-Dirt-bike-Honda/32233548283.html
If I look at the pictures it seems to have all the cables I need. I dont know about its specs and how well it vill perform on my bike but its closer to the one i got i guess.

If I should return the R/R to Hong kong I would have to pay more than the cost of a new.

/Fredrik

 

[Sonreir]

For that price, it's worth a shot.

 

[Festman]

For that price, it's worth a shot.

This one have all the cables I need