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

Pilotx253, Ill just leave you alone, you seem to know everything so I dont know why you even bother to ask for help. Your attitude will go a long way as far as future help too.

pilotx253 wrote:

...same with both the contact point vs the electronic ignition. Weak spark both ways.

What about the battery?
Battery condition?
Fluid levels okay?
State of charge?
Holding charge?
Load tested?
Specific gravity check?

What about battery connections?
Both cable connections to terminals tight and clean?
Good solid connection where negative battery cable attaches to ground on engine or frame?

What about ignition timing?
If not already done, would check ignition timing with strobe-type timing light with F mark (not T mark) aligned with case mark at idle rpm.
Verify operation of advancer unit by watching it move back and forth (under strobe-type timing light) as the rpm's are raised and lowered.

If old OEM resistor-style plug caps were used on the new plug wires, could be an issue because old plug caps may be defective or possibly incorrectly attached to the plug wire. Hope the "new" plug wires are Dyna's which came with caps already fitted. Also hope the new plug wires are solid metal core variety (not resistor style), because IMO the solid internal wire core is easier to get better more reliable end connections.

Would also double-check fitment of connector clips on ends of plug wires that insert into the coils.

At the connection where the positive feed attaches to the Dyna coil primary, the screw head is sometimes situated very close to the metal spacer on the bolt which holds the coil to the frame. Would assure there's no wiring short between the coil terminal and spacer. As known, the metal part protruding from the coil has a hole on each end for the bolts holding it in place attached to the bike frame. And the metal-to-metal contact between the coil protrusion and bike frame is just to afford a solid firm fitment whereby the coil is held in position, and has no electronic significance or any other operational influence on the coil. The metal-to-metal method of attachment between coil and frame is coincidental and irrevelant. The coils could be hung from the frame with plastic tie-wraps and they would perform just the same.

If not already done, could perform ohm check on each coil's primary winding (between coil screw terminals) and secondary winding (between plug wire outputs), all with ignition switched OFF or bike battery disconnected.

If not already done , would install four brand-new NGKB8ES spark plugs.

There is a (red) wire from the Dyna ignition which splices to switched positive battery voltage. Would assure it being a good splice connection. Sometimes better to solder the splice connection instead of relying on the clamp-style connector.

Other non-ignition related items that should be checked are compression and valve clearances.

Good Luck!

Thanks Patton and Steell for the solid info, it is greatly appreciated. I realize it takes time out of your day....and I apologize for my frustration with the issue.

I will post my results once (WE) conquer this gremlin. Hey, you might even get a good laugh at my expense:laugh:

I have done plenty of wrenching over the years, but electrical troubleshooting is my kryptonite, and it may not even be electrical.

I will post my new results soon!

Thanks!

Put your bike year/model and location in your signature which you can edit via your profile. If you were near, it sounds like a 15 minute problem. First thing, I didn't read all the posts in this thread because it was kind of tedious and I am short on time. I am a professional vintage bike mechanic who specializes in carburetors but I understand a little about troubleshooting.

First issue: If one or more cells in your battery are sulfated, you WILL have weal spark. The battery will also not hold a charge. If the battery is good but run down, you will also have a weak spark. You can get the battery load tested which will indicated cell sulfation at any autoparts store or buy a small hydrometer and check the specific gravity in each cell by see if the little colored balls float or not. CHECK YOUR BATTERY! If you have a loose connection to the battery, it will act the same as a bad battery. The ground wire issue has been pointed out but the red hot wire connecting the battery to the solenoid can be a mass of white powder under the plastic sheathing and can also mimic the symptoms of a nearly dead battery... ok enuf on the battery.

NEXT: As far as your non-firing cylinder(s). Three issues can cause this other than the bike being horribly out of tune (timing/valve clearance issues). Lack of compression. Have you checked compression on all four cylinders. Lack of fuel. Lack of spark.

The easiest thing to verify initially is lack of spark. I saw you checked coil voltages. Next step is to swap the non-firing plug wire with the other plug that fires off the same coil. If the problem moves to the other cylinder (say #2 is non-firing; swap with #3 and #1 and #4 go together) you have one of several different issues. If you are using Dyna wires, you might want to re-install the metal parts that go into the plug cap and coil. If that doesn't do the trick, replace the plug. If the non-firing cylinder remains the non-firing cylinder after swapping the plug wires, time to check compression. If compression bad, adjust valves or do a leakdown test to determine if you have valve or ring issues. If the compression is good, you have problems with the carbs. The most likely culprit is the pilot circuit as you described cylinders kicking in after revving the bike. Take the carbs off and clean the pilot circuit and REPLACE all four pilot jets.

I bet if you did just as I described, you wouldn't have to cause ol' Steve to pull out his hair anymore. If you had your location in your signature, there MIGHT be a helper in your area that knew what he was doing and even had some hair left hehe

wiredgeorge wrote (in another thread):

I have never owned a Harley although in my advanced middle-age crisis mode, I keep getting drawn to fake tatoos and Motor Company orange and black colors

I may not have much hair left, but at least I'm not that far gone!

I copied that quote a few minutes ago and had been wondering how to use it

Only had a few moments last night:

First I tested my test light---tried it on another bike and it lights the tester right up at the plug cap.

On the KZ1000 I have all four plugs out---just a flicker of spark at each cylinder---even tried at the coil output with my tester.

Tried a brand new battery that I just purchased for a different bike, no change in spark intensity.

This caught my attention though: the coils quickly warm to the touch within 3-5 minutes, doesn't seem like they should get this warm this quick....? I feel I have a direct short somewhere...

I will be back at work on it tonight-wish me luck!

I had a similar problem and it turned out to be the voltage regulator. it ran ilke it was running out of gas at higher RPM. I am just saying don't rule it out.