78 KZ650B -- Not Starting

I've had the relay mod go bad on my 650, and replaced the relay a few times. You can do that. Buy good relays and not cheap China crap. I happen to have 2-3 BOSCH relays for sale if you can't find any local. If you stay with points and want to keep the mod, you need to stock up on a few relays and carry one with you.

Then someone pointed out (on this forum) that the relay mod is not needed when you have electronic ignition. I had transplanted a Kaw ignition into mine at some point, so I ripped out the mod and wired the coils direct to the starter relay. No problems any more.

I'll pick up a relay on the way home. If thats not the culprit, never hurts to have a spare.

I'm anxious to get home and test the theory. I figure that black wire is from the center pin of the relay (judging by the pic even) which corresponds to the normally open terminal. That would mean it always has 12v as I'm seeing. I also figure it made contact with the frame or some other wire and burned out the relay.

We'll see. Regardless, thanks for all the help so far!

The bad parts: I've really burned some time on this, $20 to get a trailer to get it home, messed up points gaps, leaked some fresh oil from the crank case removing wire clips from points wire clips (doh). Not to mention making a birds nest of the wiring on the bike.

The good parts: Other than the transmission the electrical is about the last thing I hadn't touched on the bike. I've got only a bit more snooping to do before I have a firm grasp on the complete electrical system. I'll not have to reset the points again for a bit. And when I do, I think its time for Dyan S. Anybody want to send me one?

Looks like the theory holds.

I did the hard wire without the relay and hard wired the kill switch leads. Power is delivered to the points and coils. The starter button actually works still. I didn't get it started but all systems appear functional.

I replaced the relay with a new one and that functions.

Tomorrow I'll start lacing things back up and get the points reset. I'm hopeful that the kill switch still works. If not, I'll head to Steele's to find a used replacement.

There was mention that this coil-relay mod is not at all necessary when a Dyno is installed. Is that right?

I get the idea behind the mod but I don't understand how it actually provides more power. Its the same wires and circuitry just behind a relay, right? Since I don't have the original to compare it a bit hard to visualize it.

Oh btw, I think red KZs might be faster than most but my metallic brown one goes pretty fast.

The man that designed this relay modification did it to bypass corroded wiring/connectors. Some forum members like it,others not so much.

Remove the gas tank to be able to do this check.

If you can check with a fully charged battery the input voltage to the ignition coils, then you can decide if you want to kep this modification. Put the RED Positive probe of a multimeter on the RED wiring connection of the ignition coils and the BLACK probe either on the Negative battery terminal or a good chassis ground.

Turn the ignition switch to the "ON" position(do not crank the engine) and read the voltage.

quick650 wrote:

Oh btw, I think red KZs might be faster than most but my metallic brown one goes pretty fast.

Red has always been faster.

At this point, I can't really be certain what happened first .

The picture shows the plastic housing for the kill switch terminals. The terminals screw into the underside of the kill switch itself. If you look closely you'll see that that Y/R lead (and I think the brown lead) has a small part of the sheath missing. Also, the terminal that is "screwless" was actually melted into the plastic housing.

I'm not sure at this point if the short near the relay caused this or this caused the damage to the relay. Either way, the kill switch wiring is now faulty. The switch still works. I think I can use some liquid electrical tape and cover that lead and I've already chipped the terminal up from the plastic housing.

Needless to say I found this after blowing the replacement relay and getting very frustrated after rerigging everything.

I eventually took the entire right side controls off (bars off, wires off bars, controls off bars) because the short was so hard to detect.

Right now red ones are so much faster than brown ones. And they're way faster than I am at figuring out wiring issues.

Sounds like you are on the right path - just keep at it. I know easy for me to say.

As to the relationship of speed to color - you are both wrong - BLUE is the fastest.

would this help in your relay problem?
Relays come with many different contact configurations, make sure what you're replacing is rated to handle the electrical load(AMPS).

Relay Types& Wiring Information
www.the12volt.com/
www.2carpros.com/how_to/how_do_i_check_a_relay.htm
www.bcae1.com/relays.htm