EM40-80600 Ignition Switch For 1979 KZ650B3 - Electrical Surgery?

Did the bike run ok with the old switch? What was the exact reason for switch replacement?

The exact reason for the ignition switch replacement was the destruction of the original switch. I could not get the key in because the rubber grommet that keeps the elements out had solidified and was crammed into the lock. I pulled apart the lock and screwed it up before I realized I might have been able to pop off the chrome cover and get it out that way. I've never seen this bike run. I don't know what, if any, components don't work.

The Z1 guy said the switch I bought should work just fine. He asked if it was grounded. Which, I think, is a good question. To which I answer "I'm not sure."

From what wire should I seek ground?

I confirmed continuity from each pin in the 6-pin connector of the harness to the next connector.
I found my hazard relay is missing, and one of its orange/green wires looks a little chewed up. The connectors were isolated by tape, so no grounding there.
While I was on that side of the bike, I noticed my 3-pin connector to the brake light failure indicator switch looked a little burnt/melted on the outside. The pins and inside the connector looked okay.
Also, the wire coming out of the neutral switch, where it connects to the neutral indicator wire (same side of the bike) looked like a combination of chewed/burnt/old & crispy. It was wrapped in tape.
My fuses, if 1/8 to 1/4 inch too long, work and are in one piece.

I did all this and plugged in my ignition switch again and connected the battery. This time, nothing at all. So, I'm open to suggestions. I'll be researching where to begin looking for the problem areas and start to rule stuff out.

Okay, in my defense, it's been about 18 years since I've ridden: I didn't pull in the clutch to start it.
I know...
Well, hey. One problem down.

Anyhow, what I'm left with is this 7th wire that is always hot, turning on my headlight & so on. I'll try to figure that out, and then move to the tail lights.

ok,
You'll need your meter.

Put your meter on DC V
Black meter lead on negative battery post(post is the metal portion of the battery)
Red meter lead on positive battery post
note voltage

Turn on ignition switch/engine not running
note voltage

Move your red probe to the new side of the ignition switch connector
Measure both white wires
note voltages

Move your red probe to the old side of the ignition switch connector
Measure the other wires
Note voltages

Turn the ignition switch off and redo the readings starting with the white wire on the new side of the connector and ending at the old side of the connector.
note voltages

You shouldn't need a ground at the switch.
The switch just handles +voltages.

The white wires are always hot.
The reason why I had you go to the new side of the connector is to check from that point all the way back to the battery and make sure the wire, connections and fuse are in good shape.

Going to the old side of the connector checks the ignition switch and both sides of the connector.

Turning off the switch verifies that only the white wires have power. Nothing else should have power.

When your ignition switch is on all the other wires should have close to battery voltage.

What happened when you pulled the clutch in?

My battery, not hooked up to the bike: 12.86v
Hooked up, key off: 12.69v and going down slowly.
Hooked up, key on: 12.56v and going down faster. No lights plugged in in the front.

With the key in the off position, I get the following readings. First number is on the switch side of the connector, second number is on the harness side.

Green: No reading/no reading
White: 12.48/12.48
Red: 0/0
Blue: 0/0
Yellow: 2.8 but going down slowly/2.8 but going down slowly
White: 12.74/12.73
Brown: 12.78/12.78

With the key on:
Green: 12.79/12.79
White: 12.79/12.79
Red: 0/0
Blue: 0/0
Yellow: 12.79/12.79
White: 12.79/12.79
Brown: 12.78/12.78

For giggles, battery hooked up, key OFF, I checked just the harness plugs.
Green: No reading
White: 12.70
Red: 0
Blue: 0
Yellow: less than 1 but going down at a good clip. Would take a while to get to zero if it wanted to.
White: 12.70
Brown: 0

Because I was having such a good time, I checked the back of the switch with everything plugged in and the key off:
Green: No reading
White: 12.57 & going down
Red: 2.1
Blue: 12.44
Yellow: .669 & going down at a good clip. Would take a while to get to zero if it wanted to.
White: 12.47
Brown: 12.47

So, something is draining the yellow, but it looks like my extra brown wire I added is getting power all the time from the switch?

Okay - I think I can close this topic out.

Thanks to F64 informing me that the whites are the 100% hots, I re-checked my initial work looking for continuity between the points on the EM40-80600 ignition switch and found that the empty point I thought was cold in the OFF position was actually connected to the hot. :whistle:
I moved my brown wire to the empty point that is connected to the green wire. Lights now come on when they should.
At least most of them do.
One thing at a time.

I'm going to recheck my voltage at my connector to see if I still have that goofy drain at the yellow wire.
That may be my second topic.
Thank you all.

The falling low voltage on your yellow line may be the condensor(capacitor) on your points discharging. Which would be normal.

Your red and blue wire voltages look suspect.
It may be an open circuit, a bad fuse, or a by-product of having that brown wire in the wrong place.

Good job on getting those voltage readings.