Kz440 LTD 1981

So I need some help diagnosing my carb issue/how to fix it. Start up is rough always idling very low with choke full. I have to open throttle 1/4 to a 1/2 to keep it running or it'll just idle so low it shuts off. And with the choke lever is it normal to stick toward the middle? Mine has always had a rough spot when I pull it up about half way it's hard to pull then slams fully up I oiled the lever and it has helped some... But anyway so once it finally stays running but is still warming up if I rev it slightly it hangs up around 4000rpm then if I keep going it shoots past 4000. And I basically can't ride it until it's fully warmed up because the choke doesn't have a sweet spot where you can leave it while riding until it gets warm I have to leave it off or it stalls the bike. Now once the engines at operating temp everything runs smooth chokes off, revs smooth no issues its just startup that's a pain. Is this just normal with a 30+ year old bike? Someone told me I should keep gas treatment in it because the older bikes were ment to run on older gas that didn't have so much ethenal in it... Could this be an issue? So any help would be great. It's more just annoying having to plan more time when I ride it knowing it'll take awhile to start up. I was thinking this winter I will remove the carb and do a cleaning on it.

Pilot circuits. The idling issues at warm-up could be that the pilot circuits are clogged, so the carburetor passages may need to be cleaned. Also, the idle could be set too low. you may have to bump it up a tad at startup using the idle adjusting screw, then lower it once the bike is at operating temps.

Fuel. The bike should run fine with ethanol fuel. But I think it tends to go stale faster, especially in hot hot weather, so if it's old the bike may not run as good when cold.

Airbox & mufflers. Is the stock airbox installed with stock type air filter? and does the bike have the stock mufflers?

Old cracked worn-out leaking carb holders can cause a "racing" idle.
Which results from ingestion of outside air into the fuel mixture being supplied from the carb.
Carb holders such as the following should be replaced.






Good Fortune!

The boots are brand new had them installed 4 years ago when I got the bike. I'm guessing it's the pilot circuit is there a way to clean it out without removing the carb? Once the bike is warm it idles a smidge under 1000rpm. Everything is stock, although I was thinking about cutting the trumpets off and inserting baffles into the straight pipes but I'm not sure how much work that will create in tuning the carbs.