1976 kz900 electrical connectors mess

So i have had a look under left  sidecover on the bike i owned for a little more than a week. I need help with what is what and why. There is a white plug that is not in use and some
yellow wire that was ripped off at the connector. and a black wire with a yellow stripe is not in use.Everything works on the bike exept the rear brakelight pedal switch. And the neutral light is only working  when it wants to.I dont know if this bike has a self cancel relay if it has it is not working.

On the face of it there appears to have been some "jiggerypokery" going on here (there is some suspicious looking tape work) I will try and have a look at the wiring diagram tomorrow but it looks like there has been some cutting and by-passing going on. If that is the case then you are going to need to identify what has been done before you change anything or it could end badly in a cloud of smoke   (the worst issues to diagnose and repair are always the PO created ones) On the upside it's not a complex system so shouldn't be too bad to get to the bottom of.

If everything is working except the rear brake switch, we'll focus on that first.
Locate the switch that should be attached to the brake pedal.
There are two wires( one blue       one brown)
The wires have bullet connectors on them in case you need to replace the switch.
Disconnect both bullet connectors.

Turn your key switch on
kill switch to "kill"

You want to touch the two bullet connectors together that are not going to the switch.
One blue wire connector(male connector) touching the one brown connector(female connector).

When you do this, the brake light should light up.

Does the brake light work?

Turn bike off
 

Need to see all 4 plugs and recepticals.
Steve

Do you have a wiring diagram?  There may be one in the Filebase. see link in KZR header.
Note the colors of the unknown wires & compare them with the wiring diagram.  If you still aren't sure, post the wire colors & I'm sure you can get some help here.  Also, the diagrams at Kawasaki.com or Partzilla can be useful. Partzilla is easier to use.

The rear brake light switch may need adjustment. you might be able to operate it by hand to see if it will turn on the brake light.  
My neutral switch was glitchy, so I removed the engine/sprocket cover & cleaned up the electrical connection. the terminal was loose so I crimped it a tad for a tight fit.  There will be chain sling & grunge under there, so it's a messy job.

I suspect a R/R upgrade happened here. 
Steve

It looks like someone tried installing a modern solid state regulator/rectifier unit , that makes the rectifier unnecessary.
The original regulators were bad and usually overcharge.

On my 75 Z1 (same harness as 76 KZ900) the four connections on the side of the battery case are brown (with a plug for wires to the front), white (where the rectifier plugs in), green (for the regulator) and blue for the alternator and engine sensors.

In your case it looks like the white plug not connected is the now unneeded rectifier, that can be removed. 
For some reason it looks like they plugged the new regulator into the white connector and then left the old regulator still plugged into the green socket.
I believe the old rectifier and regulator should both be removed and the new regulator/rectifier plugged into the green socket with its white connecting to the white wire from battery and the fuse.  
Does this charge ok?
Z1 Enterprises explains how to connect a new regulator/rectifier here.
Regulator Rectifier - Black - Z1 | Kawasaki and Suzuki Motorcycle Parts | Z1 Enterprises

I also attached a pic below of my Z1 connections with a new regulator/rectifier which I believe is correct.

As for the other issues, they may just be a matter of cleaning and tightening connectors.  But to trace it down there's a nice color wiring diagram right  here on this forum.
kzrider.com/forum/4-electrical/616057-z1...iring-diagram#850111


Good Luck,
Kurt

 

i would agree that it looks like it's had a regulator/rectifier conversion (can you post a picture of your R/R?) if that is the case then I don't know why they didn't simply remove the rectifier rather than leave it in there with chopped wires (which would be unnecessary, it could be unplugged and removed!!) I would suggest you start by comparing what you have to the below

 

Z1 and KZ900 have different wiring harnesses and mount points.  A KZ900 wiring diagram is necessary to get it right.  Some things are common between them but I think 76 was the year they switched from the old regulator and separate rectifier mounted under the battery box to a regulator/rectifier mounted under the left sidecover.

hardrockminer wrote:

Z1 and KZ900 have different wiring harnesses and mount points.  A KZ900 wiring diagram is necessary to get it right.  Some things are common between them but I think 76 was the year they switched from the old regulator and separate rectifier mounted under the battery box to a regulator/rectifier mounted under the left sidecover.

I have used an early KZ1000 diagram as the picture posted appears to show the stand alone rectifier (top right corner)

hardrockminer wrote:

Z1 and KZ900 have different wiring harnesses and mount points.  A KZ900 wiring diagram is necessary to get it right.  Some things are common between them but I think 76 was the year they switched from the old regulator and separate rectifier mounted under the battery box to a regulator/rectifier mounted under the left sidecover.

On my 76 LTD the regulator is mounted under the battery box and the rectifier is mounted next to the fuse box.

Moose1800 wrote:

hardrockminer wrote:

Z1 and KZ900 have different wiring harnesses and mount points.  A KZ900 wiring diagram is necessary to get it right.  Some things are common between them but I think 76 was the year they switched from the old regulator and separate rectifier mounted under the battery box to a regulator/rectifier mounted under the left sidecover.

On my 76 LTD the regulator is mounted under the battery box and the rectifier is mounted next to the fuse box.

All correct. The Z1 and KZ are different in placement and extra circuits added. I asked for a pic of the connectors and receptacles they fit into. That could have helped in solving the issue. There are wires disconnected that should be used for a clean install.
Steve