Low voltage to coils

loudhvx wrote: You swap the big green wire from the 2-3 coil with the big black wire from the 1-4 coil.
Then on the small wires, you swap black with yellow, and swap blue with red.
That makes it so the pickup and coil for cylinders 2 &3 are using the 1-4 igniter circuit, and the pickup and coil for cylinders 1 & 4 are using the 2-3 igniter circuit.
If the 2-3 igniter circuit is bad as suspected, then 2 & 3 will now fire, and 1 & 4 won't.

Ok Did this. Cylinders #1 and #4 still work fine. #3 heats up and #2 is still cold. I can pull the #2&#3 coil wire and the engine does slow where it did not before. If I pull the wire from the #1&#4 coil the engine will stop. Checking the #2 plug shows spark.
Not sure where to go from here...

Did you clean your connectors? and are they connected properly?

Old hard cracked "leaking" worn-out spark plug wire(s) can cause the reported symptoms.

Good Fortune!

OOPS! I unintentionally edited this post . SORRY!! Patton

ThatGPzGuy wrote: Old hard cracked "leaking" worn-out spark plug wire(s) can cause the reported symptoms.

Good Fortune!

OOPS! I unintentionally edited this post . SORRY!! Patton

All wires are new. I've also swapped them to try to isolate the problem.

The edit feature seems to be messed up. It has rearranged the post unexpectedly, so I will start over.

ThatGPzGuy wrote:

loudhvx wrote: You swap the big green wire from the 2-3 coil with the big black wire from the 1-4 coil.
Then on the small wires, you swap black with yellow, and swap blue with red.
That makes it so the pickup and coil for cylinders 2 &3 are using the 1-4 igniter circuit, and the pickup and coil for cylinders 1 & 4 are using the 2-3 igniter circuit.
If the 2-3 igniter circuit is bad as suspected, then 2 & 3 will now fire, and 1 & 4 won't.

Ok Did this. Cylinders #1 and #4 still work fine. #3 heats up and #2 is still cold. I can pull the #2&#3 coil wire and the engine does slow where it did not before. If I pull the wire from the #1&#4 coil the engine will stop. Checking the #2 plug shows spark.
Not sure where to go from here...

Since 1 & 4 are still working fine, that would indicate the igniter is ok.

Strange that the symptom changed slightly. My first suspicion would have been plugs and wires, like Patton said, but if yours are all new, then I'm not sure. It looks like you've done a full coil swap as well. So that leaves something mechanical on 2 & 3 rather than electrical.

I guess if it was my bike, I'd throw in a new pair of plugs on 2 and 3. It's relatively cheap, and I've had plugs go bad on me in the past, very rarely, but it did happen.

loudhvx wrote:

ThatGPzGuy wrote:

loudhvx wrote: I guess if it was my bike, I'd throw in a new pair of plugs on 2 and 3. It's relatively cheap, and I've had plugs go bad on me in the past, very rarely, but it did happen.

Tried that. No change.
Just on a lark I tested the voltage coming to the coils from the igniter while it was running. They were the same from both sides.
I can still pull the wire from the 2&3 coil while it is running and the engine will barely react.

Pulled #1 and #2 plugs and cranked the motor over. Both spark at what appear to be the same intensity. I also put a timing light on #2 and it light up when it is supposed to.
#2 plug is wet with fuel.
So... As it stands #1, #3 &#4 heat up. #2 is stone cold. I can still pull the 2&3 coil wire with no change in how the engine runs.
I think I am going to pull the valve cover and check the valves again. Although the compression is OK.
Not sure what else to do at his point besides ride it into the lake.

Would suspect a mal-function for whatever reason within the secondary loop that's adversely affecting spark quality.

Stock setup (on Z1, KZ900 and KZ1000) is resistor plug caps plus non-resistor spark plugs plus non-resistor solid core spark plug wires.

Hopefully not combining two resistor elements in the secondary loop which weakens plug spark.
For example, should not use resistor plug wires with the stock resistor plug caps.
Resistor spark plug wires should be used with non-resistor plug caps and non-R spark plugs.

Sometimes a plug cap might become internally defective, which can cause misfiring through the secondary loop.
Can use an ohmmeter to measure and compare resistance in plug caps.

If a carb fuel level is too high (which usually causes an overly rich air/fuel mixture in an otherwise perfect carb), the spark plug may become fuel fouled and quit firing, which causes the other spark plug in that same secondary loop to quit firing.
Diagnosis would be via clear tube testing.

Good Fortune!

Hello Patton,
The wires are Dyna non-suppression without resister caps. I set the fuel levels using the clear tube method on the bench but I'll check again.
This has been going on for quite a while. No matter what I change or do it usually comes back to #2 not functioning.
Thanks,
Jim

Here's a question. Could there be a mechanical/valve issue that would not show up in a compression check? I've done compression and leak down tests which does not show anything out of the ordinary.

An intake vacuum leak or even something unheard of, like a crack in the intake tract, would adversely affect combustion, but not show up on a compression test or leakdown test. A vacuum sync would show up a defect like that.

ThatGPzGuy wrote: . . . Pulled #1 and #2 plugs and cranked the motor over. Both spark at what appear to be the same intensity. . . #2 plug is wet with fuel.
So... As it stands #1, #3 &#4 heat up. #2 is stone cold. I can still pull the 2&3 coil wire with no change in how the engine runs. . . .

Would do a quick clear tube test on #2 carb without removing the carbs and with the bike held level.

Double-checking valve clearances, especially in #2 cylinder, also seems a good idea.

Good Fortune!