KZ750-4 bad igniter?

Sorry I've never troubleshot an electrical issue before. I have a 1980 kz750-4 LTD that ran fine last time I rode it two years ago. Last year it would start but ran like crap and all signs pointed to it needing a carb cleaning. I put it away and rode my other bikes. Now I am getting around to getting it running again so I started by cleaning the carbs really well and putting fresh gas in it. No start. The battery was crap again so I got a new AGM battery. This made it crank better but still no start. I checked for spark by taking out 1 plug at a time and grounding it against the engine and hitting start button to look for spark. No spark on 2 or 3 but 1 and 4 were fine. I swapped the wires over from the coils and now I had spark on 2 and 3 but not 1 and 4. That makes me think that the plugs and wires, coils are all fine. I swapped them back(the correct way) and consulted my manual. It said to check the IC Igniter by removing one of each pair of spark plugs, ground it against the head, turn bike ON and touch a screwdriver to pickup coil core to see if the plug will spark. Going through the plugs one at a time I could get them all to spark except #2.
So I assume I need a new igniter? Or is it too early to come to a conclusion and try more tests? I have ordered some deoxit and plan to go through my connections once it comes in but looking at everything right now there is nothing very corroded or crunchy etc...

Sounds like an ignitor. It can't hurt to check the pickup coils on the crank end for obvious damage and clean the connections which you are already in the process of doing.

I swapped them back(the correct way) and consulted my manual. It said to check the IC Igniter by removing one of each pair of spark plugs, ground it against the head, turn bike ON and touch a screwdriver to pickup coil core to see if the plug will spark. Going through the plugs one at a time I could get them all to spark except #2.
So I assume I need a new igniter?

Which makes me wonder if the problem is just the #2 plug
If there is a problem with the ignitor or the green ( I think) wire from the ignitor to the coil wouldnt both #2 and #3 plugs fail to fire ?
Might be worth you while testing plug caps and replacing a couple of plugs

Dont toss the ignitor until you have done the resistance checks ( a multimeter is a good investment)
Page 235 approx in the Kawasaki shop manual

As JR mentioned, if the #3 sparked, then #2 should also spark. They spark at the same time. If the test was done properly, this suggests a problem with the 2-3 coil or plug wiring.

Whatever you do, don't try to make a spark without giving a complete path for the spark. This means the plug wires, for each coil, must be in a way where they can spark to the engine (or each other). If they are disconnected and too far from the motor or each other, you can damage the coil or the igniter, or both. The damage may only be partial, which will reduce the ability to make good spark.

How old are the coils?

Testing igniters with ohm meters is usually not very reliable. The igniters use active semiconductors which can have wildly different resistance readings, even though they perform the same task and are working correctly. If the oem supplier decides to use different transistors, the resistance check will be invalid. Also, the meter, itself, can influence the reading, since meters apply a tiny bit of voltage to get the reading. Different meters produce different voltages. The difference is especially relevant since the manual was written for analog meters. This is fine if you are measuring a resistor, but not so much when you are measuring transistors. A good igniter may fail a resistance check, and a bad igniter may pass a resistance check.

I would re-do the spark checks. swapping the black and green wires at the coils.

JR, after noticing I had no spark on 2 and 3 I switched the leads to the coils. With the lead from the other coil I was able to get 2 and 3 to spark just fine. that made me think the problem was not in the coil or plug, or plug wires. I just don't know much about how the igniter works. Doing the next test for the IC igniter touching the pickup coil, I could not get plug 2 to fire. that made me think there was a problem with the igniter. But I don't know how to rule out it being the pickup coil. They looked to be in good condition, and it worked to fire plug 3 so it must be the igniter?

Loudhvx: As JR mentioned, if the #3 sparked, then #2 should also spark. They spark at the same time.
-according to my book,
The ignition fires through 2 spark plugs wired in a series. If one of the plugs fails to fire, so will the other. If one develops a weak spark, so will the other.

KZ802 wrote: Loudhvx: As JR mentioned, if the #3 sparked, then #2 should also spark. They spark at the same time.
-according to my book,
The ignition fires through 2 spark plugs wired in a series. If one of the plugs fails to fire, so will the other. If one develops a weak spark, so will the other.

Right. So if one has a good spark, and the other does not, it is not the igniter or pickups. It would be the coil or plug wires. In order for at least one of the plugs, of the coil to fire, the igniter, for that circuit, had to work. The other plug failed to spark because the plug wire was shorting, or the coil had some internal short (that is, a pathway for the thousands of volts to arc across, other than the plug itself).

Have you checked the sparkplug caps? They contain a 5000 ohm resistor,that can become intermittent, How old are the sparkplug wires? Original? If you replace them,use the copper wire type,as the carbon fiber types usually fails after a while.

I'd get a new set of plugs and start over. New caps too if need be.
Steve

Tried to rule out the cheap stuff first. Got a set of plugs from auto part store on my way home from work, Gapped them and changed them out, no change. My deoxit came in the mail so I went through connections with that, no change. I could not find plug wires or caps locally easily so I did what I saw others on here do and cut 1/4 inch off of plug wires and reinstalled. Then the bike started right up! I am still going to replace the plug wires and caps when I can get them. I think the deoxit helped too I found some corrosion on connectors and after cleaning it was all gone. I will definitely experiment with it more. Thanks guys for all the help.

Many times it's the simple things we overlook when troubleshooting. Rather than spend $$$$$ for an igniter,check the pickup coils too.Kawasaki calls them "Pulsing coils",not to be confused with the ignition coils.

Wow I jumped the gun on that one. Tried to fire up the bike a few days later, now It's only running on 2 or 3 cylinders at a time. (still intermittant on cylinders 2 and 3). So I got new plug wires and caps. got them to show me they were firing but can't seem to have them run consistantly. I got a used set of pulsing coils and swapped them on, still not right. I guess I will keep trying to rule things out part by part.....