77 kz1000 ltd only running on 3 cylinders with dyna s and dyna coils

I'm stumped! My KZ started acting up, would run on two cylinders and eventually four....backfires when first started etc. If I warmed it up and ring the guts out of it on 2 cylinders the other two would eventually pick up....sometimes it would run on 3.

So I played with the points, gave up and did the wired george power up mod for the coils, installed the dyna coils and dyna S and it runs exactly the same. Fired it up today and took it for a spin running on 3 cylinders and by checking exhaust header temps, the first cylinder was not firing....checked for spark and would get an "occasional out of the blue spark". The plugs are new along with the wires......what am I missing? I feel I have changed pretty much everything! I Sorry for the long post and help greatly appreciated Find the solution and win a COOKIE!

Are you sure its a spark issue? Have you pulled the plug on #1 while its acting up to check?

KZ_Nue_B wrote:

Are you sure its a spark issue? Have you pulled the plug on #1 while its acting up to check?

Or put a timing light on each plug wire when it's misfiring and look to see erratic spark.

pilotx253 wrote:

I'm stumped! My KZ started acting up, would run on two cylinders and eventually four....backfires when first started etc. If I warmed it up and ring the guts out of it on 2 cylinders the other two would eventually pick up....sometimes it would run on 3.

So I played with the points, gave up and did the wired george power up mod for the coils, installed the dyna coils and dyna S and it runs exactly the same. Fired it up today and took it for a spin running on 3 cylinders and by checking exhaust header temps, the first cylinder was not firing....checked for spark and would get an "occasional out of the blue spark". The plugs are new along with the wires......what am I missing? I feel I have changed pretty much everything! I Sorry for the long post and help greatly appreciated Find the solution and win a COOKIE!

The symptoms sound like a coil problem, but you changed the coils so maybe it is the circuitry to the coils. With an intermittent electrical like this, the shotgun is the only effective weapon. I would:

1) Check (and maybe replace) the wires going from the coils to the points.

2) Check and replace the power lines to the coils.

3) Replace the fuse that runs that line.

I would also try the "side flip" tests:

1) Swap the plug wire sets side to side on the spark plug sets. Does the miss follow the plug wires or stay with the cylinders?

2) Swap the coils. Follow the coils?

3) Swap the igniters.

Either spark gets to both plugs on each coil, or you have two dead cylinders, not one.

The only way you can have spark on one plug and not the other is if one plug or plug wire is shorted to ground.

It's not uncommon to get a bad plug new in the box.

Thanks for the fresh ideas! I am going to look for an obvious short and then start troubleshooting. Thanks again and I will keep you all posted. I have tried different plugs and ran it without a plug in cylinder one while checking for spark--nothing except on a very rare occasion one blue spark...?

pilotx253 wrote:

...plugs are new along with the wires....

Are plug caps also new?

Could spray water mist over plug wiring with engine running in a dark garage to see any sparks from current leakage.

Finally got some time to diagnose....

I have 12 volts at the coils but very weak spark on all four cylinders. Coils are properly grounded. I get a strong spark through my test light and plug lead when I turn the key to the on or off position-actually get a shock.

I have replaced and checked everything except the stator, starter and starter solenoid. I installed a brand new wire harness and used a parts bike to switch out all the other electrical. Grounds are good.

Frustrated~

#253

Thanks for the help!

Coils are properly grounded

Exactly how and why did you ground the coils??

Last time I looked there were only two terminals on the Dyna coils, one for +12V and one for the trigger wire from the ignition module. Did Dyna add a third terminal when I wasn't looking?

According to the installation instructions at www.dynaonline.com/skins/downloads/Default.aspx they still only have two terminals.

This is really kind of funny, nine times out of ten when someone has a drivabilty problem (missing out, etc) they blame the carbs and never even look at the ignition system, but you have all the symptoms of a carb problem and are blaming the ignition


In your original post you said:

So I played with the points, gave up and did the wired george power up mod for the coils, installed the dyna coils and dyna S and it runs exactly the same

Since you replaced the whole ignition system and there was no change, shouldn't it have occurred to you that perhaps the problem isn't with the ignition system?


By the way, loudhvx has just posted a crystal clear schematic of the Dyna S and coils install on a KZ1000 in this THREAD , you might want to take a look at it.



Assuming that the two plugs you took out of the non-firing cylinders were wet with gas and fouled out (since you haven't said), I suggest that you take a look at the fuel levels in the float bowls, there's a reasonable possibility that the fuel levels in those two are set to high.


You "really" should invest in a Factory Service Manual, if you had one, and you spent just one day doing a "complete" tune-up, and following the steps in the manual to troubleshoot any other problems, you would have fixed your bike in that one day.

I have over forty years of experience twisting wrenches, and that's how I earn my living, and I have a manual for every single bike I work on, that's KZ650, KZ750 twin, KZ750 four, and KZ1000/1100, and I refer to them often.

I be looking at a plugged pilot jet or internal carb plugging myself having been thru that exact same senario with the Dyna S and Dyna coils. Plugged pilot jet fouls the plug. I was wondering what to do myself about a better ground because after the coil mod Im still at 11.75. Going to try and remove the ground to the engine rear mount and clean it up some

Last time I checked my manual it never mentioned dirty carbs causing a very weak spark on all four cylinders. The carbs have been cleaned and floats adjusted.

The coils are grounded where they are bolted to the frame of the bike.

Any more suggestions....I am gonna do some additional testing tonight-this one has me stumped, even with the parts bike.

Once again it ran the same with both the contact point vs the electronic ignition. Weak spark both ways.

I swear I'm going to pull what little hair I have left out.

The "only" ground in the ignition system on the KZ multi cylinder bikes is the ground for the points, igniter, or Dyna S, and that ground is important, if you have a bad ground there then you "will" have weak or no spark.

If you don't believe me then there is a simple test that will prove I'm wrong, if you have the courage to back up your convictions.

Unbolt the coil from the bike and lay it on top of the head so it's not grounded in any way, while leaving the primary wires hooked up. Take the spark plug caps off the wires and hold both wires in one hand (I "really" don't want to see you run 30,000+ volts through your heart by holding one in each hand), make sure you are not touching the bike and have someone turn on the key and hit the starter.

Now, if you are correct that the coils require a ground (separate ground, other than the points/igniter/Dyna S provides), then nothing will happen because the coil is not grounded, so you shouldn't have any hesitation in performing this little experiment, right?

Last time I checked my manual it never mentioned dirty carbs causing a very weak spark on all four cylinders

My KZ started acting up, would run on two cylinders and eventually four....backfires when first started etc. If I warmed it up and ring the guts out of it on 2 cylinders the other two would eventually pick up....sometimes it would run on 3.

Those two statements contradict each other, you say that two cylinders run fine, but all four have weak spark. If compression and carburation are the same on all four cylinders, and all four cylinders have weak spark, then all four cylinders will run exactly the same.

If I warmed it up and ring the guts out of it on 2 cylinders the other two would eventually pick up

It takes more spark energy to fire the plugs at wide open throttle than it does at idle because of increased cylinder filling causing increased cylinder pressure, while at the same time the coils have less time to charge at high rpm (decreased dwell). Any ignition system that can provide enough spark energy to fire the coils at wide open throttle at high rpm is going to provide more than enough spark energy to handle idling.

Keep in mind that I get absolutely nothing out of spending my time and effort typing all this (with two fingers no less) trying to help you.
No one is paying my normal $50 per hour fee for onsite service, and the same people here that always argue with me are going to keep on doing it

I do it because I like a challenge, and you are certainly a challenge!

You are fixated on the ignition system being the cause of the problem (and that's a common trap that most fall into once in awhile), and the only solution is to lay the tools down and back away, then come back to it as a fresh problem to be diagnosed and repaired, and starting at the beginning. And I do mean start all over, like you have never worked on it before.

Don't assume anything, check and verify everything, because it's going to end up being caused by something you assumed was working right.