1980 KZ1000 B4 Ignition

This year I've had an intermittent issue with the ignition. Bike runs fine sometimes, but other times I lose two cylinders while riding. They will come in and go out occasionally, which gives a huge thrill if you're not hanging on tight when the cylinders kick back in!

I think the problem is in the transistor ignition or in the exciter. Both are original to the bike, so are 40 years old and still working...sometimes! Coils are new a couple of years ago...Dyna 1.5 ohm.

I was thinking of scrapping out the original system (pickup and igniter) and going to a Dyna system for 4 cylinder bikes, the same as the one they make for Z1's, as I have them installed on both my Z1's. It would require changing the coils to the 3.5 ohm models, but I'm OK with that. I just want to check to see who has done this and how successful it was?

1.5 ohm would probably stress the igniter a bit. The Dyna grey 2.2 ohm coils are pretty much an exact match for the factory electronic ignition.

If you can narrow down the problem to know exactly which two cylinders are dropping out, you can swap parts and wires around to figure out if it's the igniter or the pickups.

Many people use the Dyna S ignition with 3 ohm coils and they work well. They use more power than the stock ignition but as long as the charging system can keep up it should work fine. The bikes that tend to have issues with the Dyna S are a few of the 78 and 79 Kz650 models. I don't recall anyone with a 1000 having any issues.

If you do swap over to the Dyna S, please don't toss the pickups or igniter. Someone will want them. The remaining good pickup can be used. I'm searching for replacement pickups. Even if the igniter is bad, the connectors will come in handy for anyone making an HEI replacement igniter.

I took the bike out today and it dropped out as expected. Turns out it's 2 and 3. I know I said the Dyna coils were 1.5 but they are actually closer to 2 ohm. I checked the one for 2 and 3 today and it's fine on both the primary and secondary windings.

I may still have a problem with the pickup or the igniter but I found another problem while inspecting the coil. The #3 plug wire was making intermittent contact with the connecter that plugs into the coil. I replaced it with a new one but then it started to rain, so I couldn't test it on the highway. Not sure if I solved the problem.

The B4 stator is different from Z1 but I think it actually puts out a bit more power than a Z1 stator. So I think I would be OK for power. Both my Z1's have Dyna ignition (but original coils) and I thought it would be good to have all three bikes wired the same. I think you've confirmed my thinking that there is nothing wrong with going that route as long as the coils are higher resistance.

So a little more work trying to source my intermittent problem. Both coils check out OK with 1.9 ohms on the primary and 13.6 k ohms on the secondary. Took the bike out for a test and at least one cylinder crapped out on my. I was able to pull the plug wire for #1 and noted no spark. So I went home on 500 cc and changed out the plug wires for #1 and #4. Could not get back out to ride due to rain so waited til today and went for a 50 ride where all seemed fine. As I was decelerating into the town turn, the bike went down to two cylinders again briefly. Before I could pull a plug wire it switched back to 4 cylinders. So I'm now going through everything to see if there are any issues that I might have missed.

Voltage at the coils is 12.2 volts with ignition on but bike not running. Interestingly, when the bike is running voltage drops to 9.5 volts at the coils. (I have done the WG conversion) But it's still 12.25 volts on the intake side of the ballast resistor. Of course, coils are on the downstream side.

Plug wires are silicon core 8 mm dia. I thought maybe one of them or even two were shorting out after heating up, hence changing out #1 and #4. But that didn't solve the problem, so will change out the other two and try again. If that doesn't fix it I guess I'm into new higher resistance coils and a Dyna pickup.

Hey if itsworth trying I have a breaker plate with pickups that did work... the old worked great when parked statement... I’d ship Them to you for a test...

Mikaw, thanks for the offer. What you are showing looks like what I have now, except you have two igniters. I may take you up on one of the igniters but am still messing around with the coils and plug wires to eliminate them as suspects. Once that's done I'll move back one step and check the resistor, then the igniter.

Somehow I think engine heat is a factor. When the engine is cold I have no issues. It's only after it warms up that I start to have problems. Makes me think it's a connection that goes faulty when it heats up. These intermittent issues are a beotch to find.

Several years ago the plug on my igniter (for the pickup) self destructed so I installed male/female connectors on both the pickup and the igniter. I would have to do the same to yours if I go that route, but I'm still leaning in favour of 3.8 ohm plugs with a Dyna DS-2 pickup. I have the pickup on both of my Z1's, running with original coils. Your coils are originals too I see. Are they not hardwired?

HRM, anything in that picture you need is available... all that ignition is from a 1979/80 correct? I can’t see having any need for them... I have no plans to build a correct bike that year... if you’d need to change the connectors in the igniter I’m ok with that...

You may be able to test the pickups by taking the cover off and heating the pickups with a hairdryer.
Use an infrared thermometer as well to keep an eye on the temp.
Fire up the bike, heat up the pickups.
If you get a failure, cool that pickup down with compressed air to see if if comes back online.
My pickup failed in this manner except I tested them off the bike with a hairdryer and an ohm meter.

That sounds like a neat trick! My wife is away right now so the hair dryer is available....if you all promise not to tell!

If your coils measure 2.2 ohms or higher, you shouldn't need a ballast. That will greatly reduce the potential to create spark. If you then have some problems with the plug wires being questionable, the spark will stop after a bit.

I would get some new 3.0 ohm coils, and eliminate the ballast resistor and try it with all new wires. I prefer suppresion wires with no resistors in the plugs or caps.

You never want more than one resistive element in the spark path, be it wires, or plugs, or plug caps.

I recommend the 3.0 ohm coils because they should work with the factory system (as long as the motor has near stock compression, not higher) and also work with the Dyna S. Make sure it's the full size 3.0 ohm green coils and not mini-coils.

That's what I was looking for...an opinion on going to the Z1/early KZ setup with 3.8 ohm coils and a Dyna pickup. That's what I use on my Z1's but I didn't want to spend the money before hearing from riders who have done it.

I don't know what the power dissipation rate is for the resistor (don't know the amps) but the voltage drop at the coils is about 2.7 volts.

Current coils are 1.9 ohm primary (Dyna) and 13.65 k ohm secondary and they test out fine.

I ordered a set of coils and a pickup from Fortnine. I decided to use them because they are Canadian, so no hassles with the border.