#4 Plug Fouling

my carb does have the choke plunger. is this soft material a metal?
all of the pieces that are inside the carb for the chock are metal and nothing appeared to be erroded. they where very clean.

What Patton said, about the plunger, is what the problem was on my KZ900. I had the EXACT same situation.

Choke plunger on Mikuni manual slide carb has a rubbery cushion on end of choke plunger to seal off entry of fuel from the enrichener circuit.

Don't know if the cv carb choke plunger does or does not have a similar such cushion. But would presume it does (and might be wrong).

Am wondering if the pilot jet itself in carb #4 might be damaged (perhaps enlarged from over-zealous cleaning) or the wrong size or defective for whatever reason so as to allow excessively rich pilot mixture.

Here for reference is the carb diagram from kawasaki.com. I would suspect something amiss in the pilot jet or associated part.

I don't have an FSM covering the 1981 KZ1000-K LTD to help with diagnosis in this case.

Good Luck!

[Click on image for better view]






REF NUMBER PART NUMBER DESCRIPTION QUANTITY US CA CN REMARKS


220 220B0406 SCREW PAN HEAD 4X6 14


220A 220B0510 SCREW PAN HEAD 5X10 14


220B 220B0514 SCREW-PAN-CROS 16


461 461F0500 WASHER SPRING 5MM 16


11009 11009-1240 GASKET,CARB. PLUG 4


11009A 11009-1241 GASKET,FLOAT CHAMBER 4


11009B 16038-022 "O" RING 4


13169 13169-1190 PLATE, LOCK 4


14025 14025-1359 TOP-CHAMBER,MIXING 4


14043 14043-1010 FILTER,FLOAT VALVE 4


16009 16009-1085 NEEDLE-JET 4 X US


16009A 16009-1086 NEEDLE-JET (Canada) 4 X CN


16012 16012-1010 CAP-STARTER PLUNGER 4


16012A 16012-1011 CAP-STARTER PLUNGER 4


16014 16014-1014 SCREW-PILOT AIR 4


16016 16016-1019 PLUNGER 4


16017 16017-1086 JET-NEEDLE 4 X US


16017A 16017-1087 JET-NEEDLE (Canada) 4 X CN


16030 16030-1016 VALVE-FLOAT 4


16031 16031-1013 FLOAT 4


16055 16055-010 PLATE,NEEDLE 4


43028 43028-1025 DIAPHRAGM,VALVE 4


92022 16034-001 WASHER MAIN JET 4


92037 16008-014 CIRCLIP 4


92043 16032-008 PIN,FLOAT 4


92055 92055-044 "0" RING 4


92055A 92055-1059 "O" RING,CHECK VALVE 4


92055B 92055-1105 "0" RING 4


92063 92063-1100 JET-MAIN,#A127.5 4 (RACING USE, (RACING USE


92063A 92063-1101 JET-MAIN,#A122.5 4


92063B 92063-1102 JET-MAIN,#A125 4 (RACING USE, (RACING USE


92063C 92063-1106 JET-MAIN,#A120 4 (RACING USE, (RACING USE


92063D 92063-1107 JET-MAIN,#117.5 4 (RACING USE, (RACING USE


92064 92064-1036 JET-PILOT,#A37.5 4


92066 92066-1051 PLUG,PILOT SCREW 4 X US


92066A 92066-1064 SCREW,DRAIN 4


92066B 92066-1086 PLUG,CARBURETOR 4


92066C 92066-1087 PLUG,PILOT JET 4


92081 16022-016 SPRING,PILOT SCREW 4


92081A 92081-1363 SPRING,DPHRGM VALVE 4

88alltrac wrote:

...Carbs are all cleaned out. (i completely disassembled them several times and dipped them in carb dip, boiled them in lemon juice and sprayed them out with carb cleaner as well as running a guitar string into small openings)...I put a new spark plug in and within a mile of driving it starts missfiring. I pull the plug and it is dark brown/black and wet. Put a new plug in and the same thing happens again....

I realize it seems almost unthinkable that the carb pilot circuit air passage might still remain partially blocked. But the symptoms do indeed point to such blockage. Would concentrate on the pilot circuit air passage from intake until reaching the pilot jet. If not already done, would use an entire spray cannister of carb cleaner through the air passage, followed by blowing out with compressed air.

And also assure that pilot air screw is not damaged, especially the pointed tip. Basically to assure that the adjustment screw is in fact properly operating to admit (meter) sufficient air to the pilot circuit mixture.

Am thinking a pilot circuit's excessive richness is caused by either too much fuel (fuel passage, including pilot jet and related parts) or too little air (blocked air passage or improperly operating pilot adjuster screw) or some combination of those issues.

Good Luck!

how do i tell which passage is the pilot air passage? i will give her another cleaning.

as far as the pilot jet and the air screw. i swapped these from one carb to another and no change.

and last but not least i am pretty sure my choke plungers where all metal(brass i think). i dont remember any cushion.

just blew an entire can of carb cleaner through the 2 small holes at the opening of the airbox side of the carbs. i am pretty sure one of those is the pilot air passage.
air screw looks to be in good condition.
choke plungers have no rubbery or cushiony part to them. they are just a slug of metal with a kind of a point sticking out farther than the slug.

battery voltage is 12.76 volts off, 12.48 at idle, and 13.99 at 4000 rpms.

i got discouraged today and tried to take it in to someone to work on it. i drove around for 2 hours from shop to shop and no one will work on it. each shop said go talk to these guys they work on older bikes. as soon as id get to the next shop they said we dont work on old bikes go talk to these guys.
it was frustrating.

I fought this same problem for months on my 77 KZ1000. Mine turned out to be a buggered up needle jet. This is the brass orifice that the needle goes through. It had spiral cuts in it, which makes me think someone ran a drill bit through it. It's a long shot, but you might check out yours.

that could be a possiblility. i might have to try to take a look at mine next time i pull the carbs. although it would be really hard to detect a small difference in size unless it was physically scratched up or something.

it seems to be intermittent lately. sometimes it will be so bad that it is hard to ride almost. and then sometimes you barely notice it, just a small amount of vibration.

sometimes the pipe is pretty much cold and other times it is hot but just not as hot as the others.

88alltrac
I was reading that you had removed your pollution crud from your motor.
What did you do with the Float vents ? did you plug them, take a look at this picture the two lines showen, must be left open.
i126.photobucket.com/albums/p90/mycods/CopyofCIMG2667.jpg