Topic: Regulator and Rectifier Wiring

[timbo750]

Hello to anyone that can help

I have purchased a modern regulator/rectifier to upgrade on my CB750 build, I got one for a late model GSXR600/750 as it has the same number of wires according as the CB wiring diagram in the hope it would make life easier.

There are 2 plugs on the unit, one with 3 wires -all black and one with 4 wires - 2 black/red stripe and 2 black/white stripe. I have been searching the net for a wiring a diagram but struggling so far to find one so I was hoping some electrical guru might be able to help.

I figure the 3 black wires are from the stator coil and I can connect to the 3 yellow wires on the CB, but the other wires are a bit of a mystery to me. Could it be as simple as the 2 Black/Red wires are both positive and the 2 black/wire are both negative and the unit puts out 2 separate circuits to suit the bike it comes from. If this is true then what do I do with the 2 wires from the field coil?

[scottly]

Tim, that reg/rect appears to be a shunt regulator for a permanent magnet field, which "shunts" excess power to ground, vs the electro-magnet field our bikes use. That is the wrong part.

[timbo750]

Doh!

[timbo750]

Any idea where to get one that is the right unit?

[timbo750]

Well I will be honest to not reasearching enough, that's not to say I did no research but just not quite enough. I found a topic in the "tech tips" section with a link to Oregon motorcycle parts who specialize in this sort of thing and I ordered upgeade unit that will plug straight into the wiring harness.

[Bodi]

That will be your best choice. There are many options using later Honda or other make's reg/rect units... even car regulators and various rectifiers. The Oregon unit should plug in and work, retaining the original harness intact.
You can use a shunt regulator by forcing 100% alternator output, but the alternator wasn't designed for that and tends to overheat. Some power will be wasted as well, but not enough to miss... the CB750 alternator maxes out at something around 200W, about 0.3 HP.