1981 KZ550A2 Update

Yep, that's the,plan., i had read on your carb page about this and am prepared to measure adjust as,needed. R

I pulled off the carbs tonight in prep to measure and install new fuel valve seats and needles. The leak continues and I noticed that when I fist moved the bike a bit another bowlful of gas drained out the overflow tube. More than I think would seep due to float height. I think this confirms had fuel seats and needles. What do you think? Parts come tomorrow. R

A bowlful?
Steve

1-2oz. I think the spring is shot in the #2 float vale needle. It leaked about a 1/2 oz over the last two days. I lifted the seat and pulled the tank and pissed that amount right while I was standing there,just ti spite me R

Pesky little things. :dry:
Steve

I recently invoked a similar problem on myself, while switching fuel filters. I have all new OEM needles seats and gaskets. switched the filter and it just started pissing out, I reckon some gunk is keeping the needle open. going to clean the carbs and install what I had originally hoping that will calm the beast and get it working properly.

They seem to be very sensitive to gunk and other crap.

If you don't already have an inline fuel filter, it might help to install one.

This video will take a bit to upload and bit longer to reach 1080 60p resolution.

It shows the proper (to the best of my ability) bench synch and throttle stop set from the Kaw FSM. Fuel valve assemblies tomorrow or the weekend. Peace.

R

I'm coming in on this topic late so forgive me if I restate something here...
I too have a 550a and been learning the ropes as I go with it, including the joy of removing the carbs with an air box in place.

To the issue. I noticed during one of the carb removals that carb #1 and #3 both were leaking a bit of fuel (Like teaspoon or less).
Ultimately, what I found to be the culprit was the drain screw's inner o-ring seat. It required an LED flashlight (and my other reading glasses LOL) but I noticed ancient hardened black (rubber?) gunk stuck to the carb bowl orifice where this little screw's o-ring is supposed to seat. Carb cleaner didn't remove it by itself so I GENTLY used a dental tool to rub the ick free of the seat and then kinda' q-tipped it with a twisted-up piece of paper towel.
This solved the leaking on those two carbs. I also replaced the little O-rings on these carbs as I thought perhaps they may have been crushed or damaged by compressing hard against that icky black stuff.
YMMV. Best of luck!
Oh. Since you've become a carb cleaning fiend, I would also suggest taking Steve and loud's advice on carb synchronization. I ultimately had to go there to remove random nuisances but in the end, it was pretty darn easy task (except my damn fat fingers seem to have gotten fatter! haha). I ended up buying 4 vacuum sync's at Harbor Freight for like $15 each. They worked great once I figured out to gently pinch the vacuum hoses with a clothes pin to restrict the tubes so the analog needles would calm down. I just strung a bungee cord across my handlebars to hange the analog gauges from..
Worked great!

You can make restrictors AKA jets for each line out of a piece dowel and a 1/16 drill bit.
Steve

I will check that again. Vacuum synch coming.. R

The throttle stop, from the factory, is usually set to go slightly beyond fully open. This means the needle jet opens more, without any additional air going in. This makes the WOT position richer than what the jetting would normally be just slightly below WOT. On hot days, if you hold the throttle wide open, and get up to speed (triple digits), then slightly close the throttle, you might get the sensation of the bike going faster instead of slowing down. This is because the throttle stop was beyond fully open, and the mixture was too rich. By slightly closing the throttle, you reduce the fuel flow, but still have full air flow. This makes the mixture more correct for maximum power, and the bike will accelerate, or at least not decelerate. Once the jetting set properly, WOT performance will be best when the throttle stop is set so the slide is just flush with the roof of the carb bore.

Shimming the needle alters the WOT position, so the throttle stop has to be re-set after shimming the needle. The Tk22 website shows how to measure the throttle position from the top, so you don't have to take the carbs off to adjust it.

Switched over the needle valves and seats. Measured float height to 18mm on each carb. I will say I am certain all the needle were shot and the springs on each old one was severely weak. Compared to the new they were several inch lbs less strong. The new ones had at least 3 times more spring tension. Will do clear tube test tomorrow or Sunday to verify fuel height and then reinstall and see if my leak is fixed. Pretty sure this is it. R