1980 KZ1000 LTD lean and rich and rough running at WOT.

Multiple problems: 1980 KZ100 LTD Stock internal with Pods and Jardine 2 into 2 exhaust(like stock).

I just went through the carburetors for the second time and put back some stock parts. I put my original inlet seats, and inlet needle valves and I think it’s called a pilot jet. It’s a small jet next to the main jet.

Problem: Three of the plugs appear almost white which means it’s running lean. One plug is almost black, meaning that cylinder is running rich?

Here are my questions:
Q1- Could the lean condition be related to the fact that I installed “Pods”? The carbs had 102.5 jets and I increased it to 105. The local Kawasaki shop shows it should have had 107.5, so I then I really think it should have 110 or more in there. Should I raise the neele by one notch?

Q2- Could the rich problem be caused by a cracked coil and a misfiring plug?

The bike runs pretty good with a rough idle and a popping out of one of the two tail pipes. It has a good midrange and runs down the highway at 65 – 70 pretty smooth. At WOT, it stumbles around 6500 up to redline.

It has always done a lot of popping at an idle and low speeds.

Any help is appreciated. If you are around Kansas City and have any jets to try, let me know.

Thanks,
Scott

Make sure carbs are synched to try and explain the one different cylinder. The lean condition could have something to do with the pods, or you could have an air leak. One way or another you are getting too much air. This is causing the plugs to look like they do. This is also causing the popping issue. The fact that it isn't bad until you get rolling at high speed leads me to believe you are jetted to lean. My experience with air leaks is that they have a uniform affect, or a more pronounced one at midrange rpm, usually regardless of actual vehicle speed.

Sounds lean. make sure the fule levels in the bowls is correct, then increase main jet size until you get strong performance from mid range RPM to redline (wide open throttle). Then increase pilot jets to get good dile and low speed running. Adjusting needle position will improve hesitation at small throttle openings but does nothing to improve wide open running.

I don't know if pods can be dialed in for your engine, sometimes pods don't run right but they can be improved.

Thanks for the input! I think it's solved now. I did not mess with the needle settings since BountyHunter told me what that would do. I checked the levels using the clear tube method and they are all very close to the level of the seam between the carburetor body and bowl. I purchased some 107.5 jets and replaced the 105's I had in it. (102.5 is stock for this bike). I put a new spark plug in the hole that looked rich and I took it for a ride. It runs real strong, but still has the popping at low speed. It's actually always had that popping at low low speeds. Now it runs smooth throught he power range and I think it's pulling pretty solid clear up to about 8,000. It revs pretty quick now and seems to be more solid feeling after each run through the gears. Oh, and while I had the bowls off, I adjusted the float just a little on the one that was black before.

I still need to sync the carbs!

I think I will leave the pilot jet alone for now.

Thanks Liberty Cycle in Liberty Missouri for being the only real Kawasaki shop in my area! Nobody else had a selection of jets.

I'll let you know how it does on the ride I'm doing this weekend.

Popping att very low / idle revs could indicate lean mix. Try to open (or close) air/fuel mixture screw 1/2 turns.

(Do you know whether it´s a air/fuel or a fuel/air -screw? If it´s on the engine side of carb body then it´s usually fuel/air i.e. opening it means richer mix and closing (turning in) means leaner. If it is behind carb body (air filter side) then it should be air/fuel and the adjustment is vice versa.)

You could also raise needles 1/2 notch to give it just a bit more fuel on 0-1/5 throttle.

And definately synch carbs.

When mine was popping at low speed and also when I let off the throttle, it was definitely too lean on the pilot jets.

I will definately try these suggestions when I get back from my trip this weekend. I've been preparing for a ride and I feel like it will make if fine the way it is and I really don't have the time to make the tool for Syncing the carbs, or buying the pilots. I may see about raising the needled one notch. I looked for air adjustment screw and didn't see any. Each carb does have a small circle that looks like an adjustment block off that I have seen on some newer cars. Back when cars still had caburetors.

Scott

Here's an update for those that might be interested. I rode the bike on a trip this past weekend and it carried me over 900 miles! It ran pretty good, but would have a little studder at cruising speed around 55 - 60. Then other times it would run real smooth. About 200 miles in, I noticed that one carb was leaking out of it's overflow about as much as it possibly could. I guess some debri from the tank must have gotten in the bowl. At about 400 miles or halfway on the trip it quit running out and rand just the same as it did before. When on the throttle it screams like it should, but I can tell it must need the carbs adjusted because one spark plug is still a little dark. Anyway I just wanted to thank you guys for the advice you gave, and let you know the work paid off because it made the trip fine! I am still going to do the sync as soon as I can.

Thanks,
Scott

900 miles is pretty good for a test ride:) If one or more barb starts overflowing try to close petcock, run carbs almost empty to open needle valves and then open petcock again to fill carbs and close again. Repeat this a few times and maybe it looses the little debri and starts to work again. Worked for me once.

Z1109R,
Funny you should suggest that..... I had the tools with me to take the carbs apart on my trip, but I didn't want to slow down the group. So I figured if I back off the petcock while at highway speeds so the carb would use all the gas it was getting then it wouldn't overflow. Well, I did this and starved the carbs several times before I got it set where I wanted it. Now that you suggest that as a solution, I bet that is what cleared my carb for me. half the ride I was cutting off the fuel as I approched each stoplight, or gas stop. I really didn't like watching all that golden liquid pooring on the ground. lol

I figured this out 2 years ago when riding in Riga, Liatvia (about 500km from home) with a dozen other bikers. Didn´t want to slow them down either:laugh: When in deep s..t you´ll get new ideas I guess:P