78 KZ400 Lighting - Signals & Gauges

I'm working on a 1978 KZ400 B1 and I'm having some weird wiring issues. The bike was obviously tampered with by a PO, so I'm trying to sort through the mess.

The front signals work, and so does the signal light on the dash.

Neither of the rear signals work, and neither of the gauge back lights work.

Within the headlight bucket there are a few loose wires that I am having a hard time tracking down.

1) There are two female adapter blue wires coming from the main wiring harness that do not have a home.

2) Each of the front turn signals has a second wire that goes to nothing. Seams that this should go to the back signal, but I tried connecting them directly to test it and I got nothing at the rear still.

3) There is a plastic adapter with 2 wires (orange and brown) that goes to nothing. Based on the diagram this is in the turn signal circuit... but where should it be going?




4) There is a brown wire with a double female bullet adapter with nothing connected

5) And a brown/white wire with a female bullet connector with nothing connected

Any help appreciated!

Color Codes On Most Kawasaki’s (written for 1980’s bikes)

HEADLIGHT
RED with BLACK stripe, High Beam.
RED with YELLOW stripe, Low Beam.
BLACK with YELLOW stripe, the ground circuit.

I suspect you may have extra, unused circuits, possibly for heated grips, or vest. If you connect the wiring up, and these are left over, get a multimeter, and check these to ground with the ignition key to the "On" position, and the run/stop switch, to run. You should see battery voltage.

BRAKE/TAIL LIGHT Can be an # 1157 dual filament bulb
RED, Running or Tail Light.
BLUE,(sometimes with a Red stripe) Brake Light Circuit.
BLACK with YELLOW stripe, the ground circuit.

LEFT FRONT TURN SIGNAL Can be an #1157 dual filament bulb
GREEN, Left front turn signal circuit.
BLUE, Left front running light circuit.
BLACK with YELLOW stripe, the ground circuit.

RIGHT FRONT TURN SIGNAL Can be an # 1157 dual filament bulb
GREY, Right front turn signal circuit.
BLUE, Right front running light circuit.
BLACK with YELLOW stripe, the ground circuit.

LEFT REAR TURN SIGNAL Can be an #1156 single filament bulb
GREEN, Left rear turn signal circuit.
BLACK with YELLOW stripe, the ground circuit.

RIGHT REAR TURN SIGNAL Can be an #1156 single filament bulb
GREY, Right rear turn signal circuit.
BLACK with YELLOW stripe, the ground circuit.

This is all accurate information... but I don't see how it helps me?

I have the wiring diagram, and I have checked the bulbs.

Check the grounds(Usually a BLACK with YELLOW stripe), and places where a screw fastens a ring terminal to the frame, as rust & corrosion reduce the effective ground. Take a M6 X1 Tap, and carefully clean out the nut or threaded area.

Also do this:

Cleaning Motorcycle Electrics

Get some of the De-Oxit DN5 electrical contact cleaner and figure on spending a good day going from the front of the bike to the back. It’s a plastic safe cleaner/preservative. www.deoxit.com is their website, and can be purchased at most electronic supply stores.

On the older Kawasaki's, and other makes, a majority of electrical connectors are inside the headlight housing requiring removal of the headlight, then the fun begins.

Do one set of electrical connectors at a time to avoid mixing up what connects to where. Usually disconnecting, spraying with De-Oxit DN5 and reconnecting is about all you'll need.

However, when encountering the green crud of corrosion, a brass wire brush may be needed on the pins you can reach. Some 400-600 grit wet and dry sandpaper strips rolled into a tube should reach the male and female pins in the more difficult to clean connectors.

Smoker’s pipe cleaners, cotton swabs and wooden toothpicks work as cleaning aids.

Really small electrical connectors may require the use of a welders tip cleaning tool assortment.

Most pins in the connectors are coated with a thin plating of tin, and others may be nothing more than copper or brass.

If moisture is added, the resulting corrosion lowers the voltage/current being carried causing dim lights, slow engine cranking, slow turn signal response and lower input voltage to the ignition coils resulting in weak spark.


The left and right handlebar switch pods will need attention too as they have circuit functions like turn, horn, run/stop, and start. If you discover the soldered connections at the switches are crumbling, I’ve got a repair procedure for this, just ask.

Usually a spritz or two with actuation of the switch is about all needed for these switches unless corrosion is detected and then careful disassembly is required.

The ignition switch may or may be not sealed to allow spraying the internal contacts. I urge caution if attempting to open this up as springs, and ball bearings may fly out never to be seen again!

If your bike has the older style glass tubed fuses, I suggest replacing them as vibration can cause internal failure. AGX is the type used, and most auto parts stores can get them for you.

Clean the fuse holder clips, looking for signs of overheating(discolored insulation, signs of melting). I use metal polish on a cotton swab, followed by spraying another clean swab with the De-Oxit DN5 and then rubbing the inside of the fuse clip.

All battery cables must be clean and tight for maximum current transfer. Check the cables going from the Negative(-) battery terminal/post to the engine mounting bolt

Also the one going from the Positive(+) terminal to the starter solenoid and from there to the starter motor.

If any battery cable feels ”Crunchy” when flexed, replace it as possible corrosion is inside the insulation.

Each "Bullet Connector" will have to be sprayed to ensure good connectivity, especially the ones going to the energizing coil of the starter solenoid.

The alternator output “Bullet Connectors” are usually behind the engine sprocket cover and will need inspecting and cleaning too.

The turn signal light sockets will benefit from a spritz from the contact cleaner along with the tail light/brake light socket.

Some brake light switches can be sprayed on the actuating rod, with the spray running down inside to the electrical contacts, others may be sealed requiring replacement if the switch is intermittent in operation.

Some people put the Di-Electric Grease on cleaned terminations/connectors, I don’t, as I’ve read/heard it can cause problems when it gets hot, actually insulating the connections, so the choice is yours to use or not.

I think I've covered about all of the electrical systems on the bike.........


“I spent a weekend going through every electrical connection and switch on the bike with a little scotchbrite pad and DeOxit - what a difference! Everything was brighter, gauge backlights, indicator lights, turn signals, I was getting a nicer spark, it fired up quicker, etc. Well worth my time. WELL worth it! “
From a forum member at www.kzrider.com


Re: Cleaning the many and various Motorcycle electrics.
I used the De-oxit D-5 spray on all the electrical connections of my 78 Kz1000 that had sat for twenty years .

When I parked the bike in 92 I was starting to have troubles with some of the electrical system, but after pulling everything apart and giving it a spray , reconnecting the connectors and working them back and forth a few times, then gave them another shot of spray to wash them off before the final reconnection.

Everything still works perfectly and has for over 7000 miles this year.

I am extremely happy with the results , a lot of the connectors were green when I started and after the cleaning they looked new ( shiny gold )

I found the Deoxit D-series, D-5 spray in a 4 oz can at a big electronics store called Frys in Illinois, don't get the small cans at Radio Shack , they are different and meant for computer type stuff.

1). One of the blue wire female terminals may be for the speedometer light and the other one may be unused & probably serves as an accessory lead?

1). The speedometer light has a blue wire & a yellow/black wire. It probably has a very simple pigtail.
The bulb socket has a rubber damper that press fits into the speedo. So check that the speedo light is connected.

1). If the tachometer pigtail is plugged in & the wires seem correct, it could be the bulb. The tach light has the same colored wires as the speedo -->> blue & yellow/black.

2). The po may have eliminated the running lights, hence the disconnected wires.
The bike should have dual filament bulbs at the front -->> for running lights & turn signals.
The running lights should come on when you turn the key to ON & they should flash brighter when you use the turn signals. At the rear there should be single filament bulbs that only serve as turn signals.
At the turn signals, the blue wire is probably for the running lights (Fr only) and the grey is for the right turn signals (Fr & Rr) & dark grey (or green?) is for the left turn signals (Fr & Rr).

3). That 2-pin connector may be unused (orange & brown). The wiring diagram doesn't show anything hooked up to it. However, I'm not sure if the diagram indicates where it would be on the bike.

4). There is an unused double female brown wire in the diagram. Again, I'm not sure if the diagram indicates where it would be on the bike.

5). There is a brown/white wire for the engine stop switch. Does the switch work?
5). Are you sure it isn't green/white?

KZ400.com - technical tips - KZ400-B1 wiring diagram

That colored diagram is way better than mine. Helpful.

Although I think this bike has been tampered with more than I thought after seeing that, and hearing what you're saying. Both of the front signals only have 1 wiring coming from them. Meaning they are self grounding, and not running lights.

Not sure how that would effect the rear signals though.

Normal(not tampered with) front turn signals/running lights have 3 (three) wires, one for the running light circuit, one for the turn signal circuit, and a ground(Black with Yellow stripe. The rear turn signals are just that; no rear running lights.

Contact these people, as they might be able to fabricate a new wiring harness for your bike:
www.cwswiring.com/Home.php

I'm an idiot. Sorry for wasting your time.

The rear signals weren't grounded properly.

All of the gauge lights were burnt out.

Easy fix.

Thanks for the responses guys.