Regulator/Rectifier wiring help

Hi all,

Ive been building my KZ650 for about 3 years now and am on the verge of finishing it (well making it rideable).
Its a 79 KZ650 C3.

I had some charging issues, which actual blew the battery to bits! I ordered a new battery and regulator/rectifier. When the unit turned up it was one for a CB750F with 8 Wires ( a 5 plug(3 yellow, 1 white, 1 black) and a 3 wire plug (red, green, black).

So me being my impateint self I want to try wire this ne reg in.
I know-
Red is +
Black is signal
Green is neg
and if I hook 2 Yellows up apparently it will work?

What about the Black and White wires on the 5 plug harness though? Do they need to be hooked up to something?

Help please!

And can the 'signal wire' go directly to earth, thats where it seems to eventually lead on the wiring schematic?

I would think a look at the cb's wiring diagram would be in order, and compare it to the kz's diagram. I know the reg/rec unit I just put on my bike is a universal unit, and the directions mentioned something about two white wires not being needed. I will see if I can find it when I get home.

I see that this is your first post, when you get a chance drop by the new members section and tell.us a little about yourself and your bike. It will give us a chance to properly welcome you and inflate our post count.

What model number is the r/r?

This diagram is for the typical Honda R/R with sense wire (installed on a Suzuki with orange power wire).

Nessism wrote: What model number is the r/r?

This diagram is for the typical Honda R/R with sense wire (installed on a Suzuki with orange power wire).

If that is a representative schematic of the actual regulator, it should not be used on a single-phase alternator. Notice only one leg is regulated. If you get unlucky and leave that one unconnected, you lose regulation.

Hazardous wrote: And can the 'signal wire' go directly to earth, thats where it seems to eventually lead on the wiring schematic?

The black wire should be switched 12v. For some reason Honda took the poor choice of using black as hot 12v DC. In DC, black is usually ground.

Not sure what the white wire is. Could be a lighting sensor, as Honda often liked to alter the charging system based on whether the lights were on or not, but without a diagram, no telling what it is.

If the white wire (or any other wire) is for a field coil, you definitely cannot use that regulator.

I think it's a bad idea to use honda reg/recs on KZ's since it is real tempting to connect that black wire to ground, to anyone casually working on the bike.

loudhvx: Can he use a Ninja 500 voltage regulator on his 79 650-C3?

I put one on my 81 650-CSR --- 3-phase alternator w the 3 yellow wires.
The r/r was from a 2007 Ninja w low miles.

martin_csr wrote: loudhvx: Can he use a Ninja 500 voltage regulator on his 79 650-C3?

It's a matter of how much extra current the Ninja regulator can handle. When you have 2 circuits delivering the same power that another bike uses 3 circuits for, you would assume each of the 2 circuits is delivering 1.5 times the power that each of the 3 circuits was delivering. So does each circuit have a 50% safety margin? Probably.

However, the 79 650 alternator is not known for being very powerful, so in this case I would assume it would be safe.

You can just leave the third yellow wire, on the Ninja reg/rec disconnected, or possibly better, tie two of the three yellow wires together, so you can at least split the load of one of the circuits. That may help reduce the temperature on adjacent components inside the regulator and rectifier.