KZ440 Carb rebuild questions, please.

Bike won't idle. Fuel petcock was leaking, rebuilt it. Pulled carbs 3 times and cleaned, still won't idle with choke off. Idles high with choke on. Inside each of the fuel bowls, there is a faded red plastic thingy. Is this plug supposed to come off ad get cleaned? If so, can I pull the fuel bowls while they're on the bike and clean the red things or whatever is behind them?? Thanks for any input. Thanks!

KZ Carl,
A bit more information would be helpful. A high idle with the choke on is normal, to a point. How many rpm are we talking about?
Won't idle with the choke off - Does that mean the engine races at a very high rpm? Does the idle speed slowly sink until the engine dies? Does it die immediately? Is the idle adjustment screw in contact with the throttle shaft and near the middle of its travel?
Your question about the faded red plastic thingie suggest to me that you do not have a factory service manual. You need one. It also suggests that the carburetors were not really cleaned. To properly do the job, the carburetors need to be completely dismantled and carefully cleaned, insuring that every jet and every tiny passageway are completely clear.
How are the carburetor holders? Are they hard and cracked? If so, they will leak like crazy. Do you have the factory air filter box in place and a clean filter installed?
Are the valve clearances within specification?

Check the back cover of this manual to be certain it covers your exact year and model. If it does, the carburetor stuff begins on page 148.
kzrider.com/modules/ServiceManuals/kz440.pdf
 

With the choke engaged, it will run at about 1200 rpm for 20 seconds, then it increases speed dramatically... going up to 4000-4500 rpm. As soon as I start to disengage the chock it reduces rpm. At about 1/2 choke it will bee around 1200 rpm for about 30-45 seconds then slows and dies. At full choke off, it won't run unless I "feather" the throttle. I do not have a factory manual. The CV diaphragms have no holes or tears and seat nicely. As far as completely disassemble the carbs, I pulled them off as a pair, removed the diaphragms, removed the fuel bowls, removed the 2 brass jets, removed the pilot screws from the top f the carbs, closest to the motor intakes, removed the floats and float "seals" ( dangly things that hang from floats with a round cone shaped tip). I tried to remove the red plastic caps, with my fingers, by turning them... they did not want to budge... and I thought maybe they're not supposed to come off and I don't want to break them. All of the parts I cleaned with Bergman carb cleaner. I Squirted all of the passage ways. I replaced the o-rings and the float seals with new from a pair of rebuild kits. It had the original air box, the boots are soft and supple. The rubber manifold boots are fairly supple too. The only way I could even get the carbs out was to move the air box as far back as it will go which is like 30mm, and pretty much gorilla the carbs out of the right side of the frame, flexing the manifold boots. I sprayed a little propane near the manifold boots and it didn't seem to change idle, but it's really challenging when he bike is not idling steady. The pilot screws are backed out 2 turns from seated. The filter on the air cleaner is like 4mm thick foam/sponge. It is not what I would consider clean, and not sure what to clean it with. I did not soak the carbs in a bath. Can I remove those red things with needle nose pliers? Thanks for the link to the service manual, and taking your time. 96 degrees in Phoenix today at 11 am... I'm a hot mess! LOL

God bless You for the service manual link! Thank You! I was looking for that, but was not in the right place. Thank You TexasKZ.

Ok, pulled the carbs, got the plastic caps off, cleaned the pilot jets. Now it starts choke on or off, really high rpm with choke on. Choke off, I can adjust the idle adjustment screw to get it idling at about 1k rpm, when I give it any throttle, it starts increasing rpm quickly, like running away.