1980 Kz1000 st help with revs not coming down

Fixing this bike for a guy.  Rebuilt the carbs. New accelerator pump diaphragm. New air box to carb boots.  When you rev it up the toms stay high unless I pull the choke lever, then she drops back down.  Did the carb cleaner spray on the boots and made absolutely no difference.  New cables.  I have the vacuum port that’s between 2-3 carbs connected to the vacuum line on the petcock.  There is a port between 1-2 and 3-4 that I have open at the moment.  They are not vacuum.  I believe they go to the resonator before the air box.  

Hoses from the carb vents on 2 and 4 are left open to atmosphere and are usually simply routed alongside or over the airbox and not connected to anything else.
Hose from the vac port on number 3 is correct and goes to the fuel tap as you have stated.
The common cause of hanging revs if not an air leak is too much tension on the throttle return cable..
 

Air leaks are not always detectable by spraying combustibles on them.  If the boots are original, I'd change them straight away.  Because if they are not leaking now, they likely will be soon.  So goes it on 44 year-old rubber.

A lean idle mixture will also cause revs to "hang"...
You mentioned that applying "choke" corrects this, which indicates a lean idle mixture.
Try increasing idle fuel / air mixture ratio. (idle mixture screw)

H.

Thanks everyone.  Ill look at it probably this weekend.  Ill come back with my findings.

Turn the idle thumb screw down? Underside/center of the carbs...

What do your plugs look like? This can be a huge tell...

 

I have the screw down.  Have her idling at about 1200 rpms.

I have to look at the plugs.

I did have the air screws about 2.5 turns out.  So, I set them at 1.5 turns now.  Just gotta get time to pull her out of the garage and test her again.

So I went through the carbs again, just to make sure everything is clear and the float heights are spot on.  I still get the hanging revs.  I noticed once its warmed up and I shut it off.  Ill start it after about 5-10 minutes and she will run alot better then before.  I revs come down rather quickly but still feel like its slightly too slow. I ordered new intake boots.  When spraying carb cleaner on them it does nothing, but I am thinking its a very very small spot where its leaking.  Thats why its runs better have the heat soak, and everything expands.  Ill find out here hopefully this weekend with my findings.
 

You might want to perform a vacuum sync, if you haven't done so already.  A poor sync can lead to an inconsistent idle.  It's time well spent.

I planned on doing that this weekend, but of course I forgot my co-workers sync gauges.  I will do the intake boots first and go from there.