need help on hanging rpms.

My carbs were just cleaned and the fuel is flowing nicely. It was a beautiful thing to actually push the start button and hear the bike come to life immediately, run right and smoothly, etc... But when I rode it.... Thats another story. My rpms idle nicely at around 1200 which is right on the money. But when i give it a shot of rpm they will either drop very slow like it does if i were to have the choke on half way or they will just hang and not drop lower than 3000 unless i give it a quick rev. Other than that everything runs smooth. Its just that the rpms hang and it is annoying and sucks not having the control over the bike that i did before the cleaning.

Here are a couple things that I have gone over and could use advice on.
Checked everywhere for vacuum leaks-no leaks at all
the carbs weren't balanced but from the look of it while i had them off, it didn't need to be balanced (synced)
The screws usually covered by the factory and not usually supposed to be reset were messed with. They were all set different from 2 1/2 turns out from seated to 3 1/2 turns.

I set them to 3 turns out. These are the screws on the corner of the top of the carbs... closest to the engine.

Am I missing something?

 

I`m having the same exact problem with mine checked all the basics now i`m in the middle of bench synchin the carbs (making sure they all open in sync)becasue i think one or two of my carbs stay open way too much and cause my bike to rev high unleess i snap the throttle, When i turn the idle screw down where it wont idle the bike comes down of the revs fine and seems to run good but the idle is low so you have to hold a little on the gas at a stop.

 

Sync the carbs- You can start with a bench sync to get close then do the vacuum sync. Once synced if you don't have a colortune start reading your plugs to get the nice paper bag tan (search on plug chops) adjust your mix in small increments.

Here is the correct order to get things running right
Check/adjust your valves (yes it matters)
Bench sync your carbs (if your bike is running fairly well you can skip this step)
Adjust your mix - colortune is best/easiest way - you can do plug reads
vacuum sync your carbs - be fussy to get them even. It can be trying
Check your mix again
If you have to adjust the mix resync - should go very quick it's just a fine tune
From there keep an eye on plug color for a bit and adjust to fine tune your mix

 

I would set the idle mixture screws back to 2.5 turns out, and perform a sync (you have to sync anytime to clean or take apart the carbs). Then check the spark plug color and go from there. Also make sure that the petcock works good and just for kicks you could try riding the bike on prime as a petcock check.

 

I just went through this 2 months ago. What it think fixed my hang up is cleaned the diaphrams again with scotch bright. and put some petrolem lube on bothe the intake and exhaust boots. To be sure what fixed them I am not sure one or the other. I did use propane and found no leaks. But the lube could have stopped a boot from leaking.

Did you check throttle cable for binding. I also cleaned the heck out of it.

 

A leak will generally cause a high RPM vs a hang at higher RPM. then decline. IF your pistons pass the clunk test most likely suspect is the sync/tuning although it is always a good idea to check for air leaks.

I just did this this weekend on my 400 - idled nice - blip the throttle and zoom to 4 or 5 k hang a few seconds then back down. Touched nothing except a quick sync and leaned it up a bit based on plug color - problem gone.

I have tuned bikes with massive air leaks (make that tried to tune) - they race out of control.

My bet is recleaning your slides resolved your problem.