Trying to get a 81 CB750F on the rode

[soundfuelled]

1981 Cb750F 20,000miles, just got it, had been sitting for over a year  
I’m having a problem with the idle not wanting to come down after the bike has been ridden for a little bit. It idles at about 1200 rpm not any lower and when I ride it around for a short bit and pull the clutch in the idle stays at about 3k and if I turn down the idle screw it dies  
Its stock and still has the air box
Recently I’ve cleaned the Carbs twice thoroughly with out taking them off the rack and every thing looks like it should, floats, jets, needles, o rings, and the side air cut off valve
Also replaced the intake boots and new air filter, and throttle cables, spark plugs and fuel filter  
The new boots do not seem to be leaking (sprayed WD-40 and starter fluid)
Checked the vacuum the crabs and the Purdy close
The choke works but there is a little play in one of the shafts (don’t know if effects any thing)
New to the forum and any advise would be great!!

[woodsrider250]

slides could be sticking a little, you've covered a lot already.

[mikey440]

try pouring a whole can of seafoam in the gas tank, it works great on cleaning inside of carbs and it does wonders for idle problems, poured a can in mine when i first got it and it run better and better everyday,
 I now use it in about every 6 tankfull of fuel just to keep things clean, also check ur throttle cable to make sure its not hangin up,,mykee440

[Re-run]

Did you replace the boots to the airbox or the motor? Did you spray the motor boots?
Sounds like something is dirty and not allowing the idle circuit to work right.

[Jreed615]

I just had my carbs cleaned and my bike is doing the same thing. My Bike is an 81 750C and I do not have the stock air box, however I am trying to find one. The bike idels good when I first start it and then after I drive it for a while it idles around 3,000.

[mikey440]

you must have the stock airbox to make those carbs work correctly, they are vacuum carbs and need stock airbox to get that vacuum,,,mikey440