Quicky Rec/Reg/Solenoid question

1976 KZ900.

I've been working on a general wire cleanup over the past week, focussed particularly on the electrical panel where the four coloured plugs plug in. Two questions.

1) Looking from the front of the bike, does it matter whether the lead coming from the + battery terminal attaches to the bottom left solenoid lug or the top right lug?

2) I have the green lead from the rec/reg going straight to the + battery terminal. Should the black rec/reg ground wire in turn, go straight back to the - batery terminal?

BTW, IMO, very usefull clean-up job in order to solder & shrink wrap all the joints and totally clean out all the accumulated oily clag in the back of the plug sockets.

Thanks in advance.

BARNEYHYPHEN wrote:

1976 KZ900.
1) Looking from the front of the bike, does it matter whether the lead coming from the + battery terminal attaches to the bottom left solenoid lug or the top right lug?

Solenoid contacts don't have a polarity, but sometimes there are multiple wires to the lugs so it's important that wires, which are always supposed to be connected together, go to the same lug. Sometimes one of the lugs will have an electrical strap on it, and will look like part of the solenoid. In that case, the wire's placement is determined by the strap. (I haven't seen a strapped lug on a KZ, but I haven't worked on many 900's).

BARNEYHYPHEN wrote:

2) I have the green lead from the rec/reg going straight to the + battery terminal. Should the black rec/reg ground wire in turn, go straight back to the - batery terminal?

My diagram shows seperate reg and rec on the 76 900. It doesn't show any green wire.

Post edited by: loudhvx, at: 2007/03/02 14:10

Loud, Thanks for the answer on the solenoid. I didn't think it should matter because all the solenoid is doing is providing a heavy duty connection, internally, between the two lugs.

I also took a look at the wiring diagram and failed to find the green wire. Strange. Actually coming out of the reg/rec, I have one white and one black BUT, the one white is split into a green, which goes to the Battery + and a white which goes to one of the fuses. The black, which wombles of into the hinterland under the seat, eventually arrives at ground. I'm not overly concerned with the green and the white 'cos I believe them to be going where they should. My question I suppose it "in perfect world" should the black go as quickly and efficiently as possible to the Battery -? I think probably that one should be a yes?

Yes, that would give the best ground to the reg, and or rec, but it's not absolutely necessary. I like having only one wire to the battery + and one to the battery -, so I use the starter solenoid lug to run all of my positive wires to. I also run the battery's negative cable to the engine. From there I run a jumper to a frame bolt. That frame bolt then becomes my ground tap. I run all the rest of my ground wires to that frame bolt. The frame bolt is in a clean dry area under the seat.


I take it you have a modern reg/rec, then. The green is likely a repair, or part of the reg/rec upgrade.

Loud, I did the same thing. I mounted a GE domestic (house)type grounding bar, with 10-12 holes in it, under the seat. I then ran an 8ga cable from the new grounding bar to the original grounding bolt on the frame, behind the back end of the tranny. Ran the Battery - to the same bolt and an engine ground again from that same bolt.

I may organize things a little differently this weekend by changing the battery - to ground bolt cable to go from battery - to new grounding bar.

The device I'm refering to as the reg/rec is black, about 2"x2"x2", open type structure, 3 plates, with 3 yellow wires going to the white plug and the aforementioned white & black wires coming from it.

Thank you again for the help.

BARNEYHYPHEN wrote:

.... I then ran an 8ga cable from the new grounding bar to the original grounding bolt on the frame, ....

8 ga!!! _WOW_:woohoo: :woohoo:

Too heavy? Too light?

BARNEYHYPHEN wrote:

Too heavy? Too light?

Well,,, it's just that 8 ga will carry a couple of hundred amps for short time spans and cable runs/distances, and will carry 40 or 50 amps all day long probably, for distances of, oh, ten feet or so.
Your starter supply and return wires are probably around 2 or 4 ga; not sure, never thought about it. I can't think why it would actually hurt anything, over-kill as it seems to have a ground wire that beefy. It does not include your starter return, does it? :whistle:

Barn, The legs of AC come off your stator. I think they will be yellow wires. Earlier Z1s had blue, yellow and red but yours should be yellow. These wires go to both the regulator and rectifier. The rectifier bridge is the thing you are describing. It is two black painted squares with the wires going between. The regulator changes voltage according to a feedback look (the brown wire going to it) and the rectifier turns AC to DC. The out from both is the white wire. This white wire goes to your battery via the lug on the solenoid and the other leg goes to the 20A fuse. Out of the 20A fuse, a 14 ga wire runs to the ignition switch. The BLUE connector is the connector into the regulator and rectifier. Some wiring behind the panel carries it to the rectifier. The green connector is the one for the rectifier bridge. If you have a solid green in this area, it is a home-made mod... Sounds like the wire from the rectifier fried (should be white/red or white, can't recall) and somebody replaced it. It is just a short bit so it might have just gotten lost.

Thanks everyone. I finished the job I was trying to do (all the clean-up) and also put me in new 8ga grounds from the tranny to my grounding block/strip under the seat and also from the frame to the same block/strip. The Battery ground runs straight to the same block/strip. I'm thinking the Starter grounds back through the engine/tranny ground wire, correct?

Should I have used something larger than 8ga?

Also discovered what is obviously the Regulator, bolted under the Battery box, with all wires running to the Green plug. Is the regulator pretty bulletproof or do they tend to go bad? Haven't take it off yet to look but are they servicable?

BARNEYHYPHEN wrote:

Thanks everyone. I finished the job I was trying to do (all the clean-up) and also put me in new 8ga grounds from the tranny to my grounding block/strip under the seat and also from the frame to the same block/strip. The Battery ground runs straight to the same block/strip. I'm thinking the Starter grounds back through the engine/tranny ground wire, correct?

Should I have used something larger than 8ga?

Also discovered what is obviously the Regulator, bolted under the Battery box, with all wires running to the Green plug. Is the regulator pretty bulletproof or do they tend to go bad? Haven't take it off yet to look but are they servicable?

id run the battery ground to the back of engine case,you can run the rest of your grounds to your ground strap.starter grouns through engine case;)

Wire, thanks for the advice. Currently running from Batt - to the new block/strip then from there, down to he engine/tranny case. I'll probably rework it as you suggest this weekend. I'll solder both the ground conming from the Batt- and the one going to the block/strip into one lug and attach to the case where I'v got the lead attached at the moment, at the rear/right of the tranny.

Whilst i'm doing it, should I go to something heavier for the Batt- to the case?

Thanks again.