only running on 1&2 or 3&4?

I put my 1978 KZ1000 back together after painting the frame and now it only runs on two cylinders. I know the coils run 1 amd 4 and 2 and three cylinders. i thought it was fuel at first but i switched the plug wires from the running cylinders 1&2 to the 3&4 cylinders that were not running. then the 3&4 picked up and the others did not. I switched the coils to a known good set and came up with the same thing. the wires are good and it has new plugs. Any ideas?

TWO bad plug wires? Try just switching one coil's wires at a time. Rule of problem solving: Never change two things at once!

Thanks for your reply. Sorry about the confusion. I tried switching the plug wires first. I got the same results though. The wires are good. I cant figure out how only one side of the coils are working?

Do you have point or electronic ignition? IF electronic, then a number of us have had a problem with an intermittant failure of one side of the ignition pick-up unit, producing the symptoms you describe. I replaced the pick-up unit with a used one from ebay, and all works great now.

Thanks for the info, the bike still has the points. I thought of upgrading to electronic but am not sure yet if i want to make the change.

Welcome to the board.
Man, I sure can't think of any reason why two coils would only be firing on one wire each, but I pretty curious to know why.
Don't mean to insult you, but you're SURE that you've numbered the cylinders 1 thru 4 from left to right (as you sit on the bike)? And you're SURE that your plug wires run from one coil to 1&4, and the other coil feeds 2&3?

I dont take any offense to your comment. I understand people have to have the correct info to help. I did number the cylinders as you sit on the bike. The plug wires are in the correct locations also. I have messed with this and am at a lose as to how to fix it. I thought i would get some fresh ideas on it. Thanks for your reply.

Skullfeast1 wrote:

I put my 1978 KZ1000 back together after painting the frame and now it only runs on two cylinders. I know the coils run 1 amd 4 and 2 and three cylinders. i thought it was fuel at first but i switched the plug wires from the running cylinders 1&2 to the 3&4 cylinders that were not running. then the 3&4 picked up and the others did not. I switched the coils to a known good set and came up with the same thing. the wires are good and it has new plugs. Any ideas?

You may already be way ahead on all this, but here are some ideas.

To confirm exactly which coil wires are sending current to plugs and/or absence of spark at the plug tips, might remove plugs from head, leave plugs connected to coil wires, and check for spark on each plug while holding plug base against head and spinning over engine with ignition turned on and kill switch in run position. Perhaps this will merely verify your findings based on actual running of the cylinders. But it will also give visual evidence of the sparking situation from the individual coil wires.

Are the spark plug caps okay? The caps with built in resistors such as the factory caps (believe there's a short piece of carbon inside) can deteriorate and impair the current getting to the spark plug. Perhaps the end of the coil wire where the cap screws into it has become wallowed out so that the cap is no longer tightly screwing into the end of the coil wire (thereby diminishing current flow through the cap and to the plug).

Are the capacitors (condensers) okay? If going bad, can impair proper signal to the coil (thereby preventing coil from operating up to specs) and also cause arcing across the points (pitting and burning the points). Bad capacitors can result in a weak spark or a spark with improper duration.

Assuming a good properly charged battery, and that the red/yellow wire is feeding full battery voltage to both coils, the left coil is receiving signal from the points through the green wire, and the right coil is receiving signal from the points through the black wire.

Are the points in good condition, non-pitted, clean, smooth and dry? And operating freely (with a little cam grease)?

Above items could cause firing problems even with perfect coils.

Probably have coils with built in plug wires. I've never used the "connector" (offered by Z1E) to affix new plug wires to an existing coil, but mention this as a possibly way to install new Dyna plug wires (which are relatively inexpensive and come with caps already installed), and which should eliminate any existing deficiencies in plug wires or caps.

Don't know of anyone who ever changed over from points to electronic ignition and then went back to points due to performance considerations.

Sorry about the length of this post -- with more time and more smarts it would be shorter. But hope it helps, and am anxious to see your bike up and going strong.

Post edited by: Patton, at: 2007/02/19 18:21

apeman wrote:

Do you have point or electronic ignition? IF electronic, then a number of us have had a problem with an intermittant failure of one side of the ignition pick-up unit, producing the symptoms you describe. I replaced the pick-up unit with a used one from ebay, and all works great now.

What is the best way to confirm that this is really the problem, instead of bad coils or any other ignition component?

Are these stock or aftermarket coils?

THEY ARE ACCEL SUPER COILS. I HAD THE COILS ON THE BIKE BEFORE I HAD THE FRAME PAINTED AND THE BIKE RAN FINE. I TRIED A BUDDIES STOCK COILS AND CAME UP WITH THE SAME RESULTS.

masospaghetti wrote:

apeman wrote:

Do you have point or electronic ignition? IF electronic, then a number of us have had a problem with an intermittant failure of one side of the ignition pick-up unit, producing the symptoms you describe. I replaced the pick-up unit with a used one from ebay, and all works great now.

What is the best way to confirm that this is really the problem, instead of bad coils or any other ignition component?

Process of elimination, or if you have the extra part just replace the pick-up unit and see if that fixes it. I had an extra pick-up unit, so it was easy to swap it in to find out if it fixed the problem. However, I did go through with trading the coils, and swaping out the ignitor to ensure they were not the problem either. I also checked all the low voltage side of the ignition wiring to make sure it was not a contributing factor. My spark plug wires are all about the same, and swapping those around made no difference whatsoever.