Ignition stumble on 82 KZ1100 D1

Hi all. This is a continuation from a "carb tweeking" post in the carb category. Carb work is done and everything running great at idle and good under load down the road, but the engine backfires on deceleration.In the driveway I have alot of miss firing when revving engine from around 3000 rpm and up. Valve clearance is good, compression is 160,140,140,160 1 through 4, new plugs and wires(with good blue spark),checked pick up coils, igniter, and coils per Kawasaki manual- all good. There are no vacuum leaks anymore and disabled the air valve system just to be sure. I have a new to me igniter that did not change anything when swapped out, and a new to me advance unit-same result. When the engine stumbles so does the new tach. I borrowed a timing light and found the mark on the advance to be about a line width off the mark on the case. Oddly enough, the other advance unit was off the same amount in the retard direction and the engine ran just a little lower RPM at idle. Both were between the advanced lines at higher RPM. When checking the advance with the timing light,IT STUMBLED AND MISSED along with the engine. Anyone know of any tests I can do to the pulse coils and igniter beyound the bench tests in the manual to get a diffinative answer on what is wrong. I am leaning towards the pulse coils because the tach gets its signal directly from there. The pulse coil unit is undamaged looking and the air gap is 19 thousands each side. What am I missing Thanks in advance for any help.

Put a voltmeer on the positive side of the coils. Then watch it while running. If the voltmeter changes as the bike stumbles, then you probably have a bad connection in the ignition switch or kill switch.

If the tach is attached to the pulser coils, then it can possibly alter the ignition timing, resulting in ignition retard at higher RPMs. The input to the tach must have a very, very high impedance in order to not affect the timing. But I don't think this would cause the stumbles unless the stumbles are 100% consistent all the time.

Did this symptom (back fire @ decelerations)occur pre-carb tweaking?

Somewhat confused where fine during road test but crap in driveway.... If electrical, shouldn't truly be any different in drive way or under road test to a point anyways... Hmmm.... :S

Unless of course as Loud mentioned, weak connection/connector pins/conductor strands oxidized/frayed during a ride "bounce/vibrations" contact goes in & out of continuity...

Tap around the harness connections while idling/holding at 2500rpms for example to see if it changes...

It will be interesting to see the outcome of this one....

Another rare cause can be the kickstand/neutral switch lockout system. Does it still stumble with kickstand up and in gear (with clutch pulled in)?

CLIFTON SPRINGS KBB wrote:

Hi all. This is a continuation from a "carb tweeking" post in the carb category. Carb work is done and everything running great at idle and good under load down the road, but the engine backfires on deceleration.

I would guess pilot system too lean or a vacuum leak.

Hi all, and thanks for all the responses. All the ideas are much appreciated.Starting with Loud's comments I pulled the ignition switch (already pulled and cleaned the kill switch, nothing unusual there), disassembled, cleaned, reassembled to no avail. Have not checked + side of coils yet.When I pulled the headlight can I did find alot of "home wiring" from past owner, so I am in the process of removing all "new" taped up connections and seeing what he did. In general the connectors and wiring are very clean so it won't be hard to spot a problem. To address Old Man Rock's ideas, yes the bike always had stumble almost to the point of not running when I got it.It was in sad shape with intake boots LOOSE, fuel system FULL of rust, gas tank pouring gas out seam,generator cover cracked and pouring out oil, oh- back to the problem- super cleaned carbs (4 times) replaced o rings, jets, and needles where needed, dialed in the idle circuit and synced carbs.Installed brand new intake boots- no vacuum leaks. Throttle snaps down to idle quickly and idle does NOT creep up during riding. I should not have said "good" running for it does stumble but takes higher RPM to start (around 4 grand) and does not seem to miss as bad as in driveway. The Spectre does not have a kickstand lockout, and does stumble with clutch in and in gear. In fact when starting off from stand still I need to rev up to about 1500 to get it moving and it still makes that clunking sound from the bottom end usually heard at very low RPM. When starting the engine cold with "choke" on it stumbles. I don't think it's too lean. I was also wrong about tach signal coming from pulse coils, it comes from igniter. I will follow up after going over wiring. A thought I had, would I be able to swap out the pulse coils and spark coils from my KZ750 Spectre, which runs great, to test those components? The pulse coils themselves look the same but the mounting bracket is not, but they look like I could mount them on the 1100 bracket. Thanks again for the thoughts.

Ohm Checking Pickup(Pulsing) Coils

The pickup coils on the Kawasaki’s with the factory supplied electronic ignition can sometimes fail or become intermittent due to heat and vibration.

1.Trace back from where the pick up coils are mounted,(under a right side CD sized cover) locate and disconnect a small 4 pin connector. Using a multi-meter set on OHMS and range of X 100 check between the BLUE and BLACK wires(#1 and #4 sparkplug wires) for between 360- 540 OHMS.

2.For #2 and #3 sparkplugs the wire colors will be YELLOW and RED, again 360-540 OHMS.

3.If the pickup coils are suspect of failing due to heat, they can be stressed using a hair dryer without the need of the engine running.

4.A replacement set of pickup coils might be obtained from a dealer who serviced the police Kawasaki’s.

5. If replacement pickup coils are not available, your next choice would be to order a Dyna “S” electronic ignition system from www.z1enterprises.com It replaces the IC igniter with a smaller module located where the mechanical ignition advancer was mounted.

6. Checking with Kawasaki.com website has determined that the Pick up(pulsing) coils are available . The pulsing coil # is 59026-1133 and replaces the older # 1002, 1012 which were used from the MKII motors until the 2005 P24.

7.Check the small 4 pin connector that the pickup coils connect to for corrosion/loose pins too.

Hi All, Checked pulse coil static resistance- 480 and 482 ohms. Past owners wiring repairs were to the main harness common black/yellow wires. Redid all unions with copper crimp sleeves and shrink wrap. Thought for sure I had found the problem because some connections barely made, and wire conductors had black oxidation coating.But still stumbling. Scatching my head again.

Start with new plugs, then wires, then coils.
Ignighters practically never go bad, but it does happen...
New pickups.

I've had stuff check out fine with instruments, then STILL be bad!

When it comes to ignition on a vehicle, if its more than 10 yrs old, I replace everything, INCLUDING THE WIRING, and the problem just goes away! :laugh:

GL!

If not already done, would assure integrity of igniter ground (black/yellow wire?) and where negative battery cable attaches to rear of engine.

Good Fortune!

Sparkplug wires and sparkplug caps should be replaced as they age and become brittle. Z1 enterprises sells the Dyna copper sparkplug wires if you want to replace them.

Hi again. 1st thing I did 3 months ago was new plugs and wires from Chris at Z1. Have checked grounds everywhere after discovering past owners wiring abilities, all looks good. Could both spark coils go alittle bad? And or both pickup coils? Could I swap out just for testing the coils from my KZ750 N1 Spectre with out hurting them or the bike? There was one problem that came with the bike that I have not talked about yet, the wrong regulator which was pumping out about 16 to 17 volts! Put in a new one before changing out anything electrical. Could that over voltage have hurt the pulse or spark coils? As always- Thanks for the help. One last thing. I stopped by the local Kawasaki shop this morning and 2 service guys listened to the bike and both thought it may need larger jets, To them it sounded just slightly lean. I am running stock jets and needles for that bike with a UNI paper air filter in the stock airbox, no foam prefilter, and stock 4 into 2 exhaust. Idle screws 2-1/2 to 3 turns out.