ignition gremlins

Ok got a question some one with a bit more knowledge than myself might have an answer to. I have an 82 kz750 that i came upon me in the last few weeks I know the bike ran a couple months ago bu at ht ecurrent time it is not. I pulled the plugs and 2 and 3 are not firing. The left coil sitting on the bike. I repl;aced both coils with another set and had the same thing happen, I took the wires from the right coil attached to the left coil and the plugs fired. I removed the tape to look at the wires and the red wire to the coils is fine it intersects with the other wires, the green wire on the left side is clean to the plug and on. so I need to figure out why these are not firing I am not an electrical geniusso I appreciate any help i can get.
Richard Law
05 fz1
82 kz750
Past bikes
00 R1, 95 speed triple, 92 vx 800, 82 night hawk, 72 gs 400.
Oak harbor Washington.

Howdy Richard.... OK, you swapped coils and found 2/3 firing. Did 1/4 fire or were they dead. Kind of an important detail when trouble shooting.

The way your ignition works; it is electrical. The red wire connected to both coils that goes back and also connects to the IC Igniter box, is the 12VDC. The GREEN wire starts out life at the right hand pickup coil (under points cover on bottom right of bike). It goes up to the IC Igniter box and comes out of that device and over to the right coil where it hooks to the ignition coil on a little lug. The green wire is the 2/3 wire.

The 1/4 wire is black and takes the same path but originates from the left pickup coil.

First... Get a multimeter and check voltage at both coils. Could be the one coil isn't getting powered. Turn on key and put meter in VDC scale. Put POS lead on the lug with either the black or green wire and the NEG lead o a ground. You should have about 12VDC on both coils at the connector for the black or green wire. If you don't have it on both, start checking back from that wire to see where the power stops.

If you have power, then swap coils. Take the 2/3 coil OFF and the 1/4 coil OFF and change them... install 1/4 wires on the old 2/3 coil, etc with the black wire connected. Do the same for the other coil but install teh green wire. Try for spark. If you get no spark. Open up both connectors in and out of the IC Igniter and clean with contact cleaner and put dielectic grease on them. You can find thiis stuf at an autoparts store.

If you still have spark on two cylinder and the cylinders are now moved to 1/4, it is likely the coil is bad. Swap coils.

If the problem stays on the original, it is likely the coil is bad or perhaps the IC Igniter or pickup coil... a manual is needed to do the electrical tests to verify those omponents.

Ok sorry, 1 and 4 were firing I swapped coils and 2and 3 started firing, so my coils are good. I checked the wiring down to the plug and all wires seem to be intact.
I checked the fuses (if that matters) everything seems to be intact. I appreciate the help electrical is not my best. I don't have a multimeter at the moment so I just swapped the coils both seem to be working. Thanks again.

The pickups don't have a green wire.
The wires to the pickups don't really connect directly to the coils, unless WG is possibly making an analogy to points.

Also, I usually find the right hand coil is the 1-4 coil and has a black wire to it. The left hand coil is the 2-3 coil and has a green wire to it.

... so you know the coils are good because both create spark.

If it goes dead again, and you do the coil swap to verify they are good, then it may be the igniter or the pickups.

You can do a resistance test on the pickups. One pickup uses a black wire and blue wire. The other uses red and yellow. Disconnect the pickups at the igniter. Measure the resistance from blue to black. It should be about 450 to 460 ohms. Same goes for the red and yellow wires.

If you don't have a meter, a similar swap test can be done if you can physically swap the black pickup wire with the yellow pickup wire, and the red pickup wire with the blue pickup wire.
This swaps the pickups to the igniter. If the spark moves to the other set of plugs when you swap the pickup wires, then it is a bad pickup (or associated wiring). If the spark stays on the same set of plugs, then the problem is the igniter (or associated wiring).

It's not easy to swap the wires, so I just make jumpers, so I can cross the wires from the pickup connector to the igniter connector.

Post edited by: loudhvx, at: 2007/05/04 01:24

This is what I wrote:

"The GREEN wire starts out life at the right hand pickup coil (under points cover on bottom right of bike). It goes up to the IC Igniter box and comes out of that device and over to the right coil where it hooks to the ignition coil on a little lug."

I didn't say the pickup coil wire connected directly to the coil. I was wrong about the wire colors off the pickup coils... I think they are red and yellow and black and blue now that I think about a stock pickup. I don't use any stock pickups on any of my bikes; use Dyna S and they have little green and black bands on the appropriate wires to remind you which is the 2/3 and which is the 1/4 wire from the "pickup".

This still isn't clear to me... you had two cylinders firing and two cylinders not firing. You swapped coils and the two cylinders that were not firing started firing? Did all four fire at this point? From what you are saying it sounds like you HAVE a bad coil.

Post edited by: wiredgeorge, at: 2007/05/04 09:15

Sorry WG, it's just that:
"The GREEN wire starts out life at the right hand pickup coil... It goes up to the IC Igniter box and comes out of that device and over to the right coil... " would presume that the wire is a pass-through on the IC igniter, implying that it connects directly to the coil. But, obviously, it can't be. (Which is why I suggested it may be an analogy, which is what I think you are saying.)

Sorry I wasn't clear on my problem, 2 and 3 are not firing, 1 and 4 are firing. I took the wires from 1and 4 coil and hooked them to the 2and 3 coil and theystared working so it seems the coils are are good. I checked all hthe wiring down to the ignition box and all seem to be good. I need to make a jumer wire for the pickup coils to see if this will get my coil firing if that doesn't work it seem it would be in my ignition box. Does this sound like a good cours of action?

Yes swapping over the pickup wires as I described above will show where the problem is. If the 2-3 start sparking (and 1-4 don't)after the swap, then it's a bad pickup. If 2-3 still don't (and 1-4 still do), then it's a bad igniter.

This assumes all the rest of the wiring is good and connected correctly.