Without a bit more detail, nobody knows.

We know what it's doing right now, but no idea what has been done.
Have you ever seen it run right?
How many miles on it?
Has anyone Worked on it? Did the problem start after someone messed with it?
You Cleaned the carb. We don't know if you are actually able to do that.

How long did it sit in storage before you got it?

Thanks for the input!

Problem came on slow.
Ran good last year.
it's the Wife's bike, 9,000 miles.
No one but me has worked on it.
I am comfortable rebuilding a carb (or a whole engine)
Vac line to the stk petcock is plugged off.

Could it be the diaphragm in the carb?

Could it be an air leak?

Has the plug been pulled that covers the idle mix screw? Did you remove the screw to clean it? There's a tiny o-ring on there behind the spring. It's easy to lose.

It might be worth spraying carb cleaner around the carb body while the bike's running, see if the rpm drops.

Check and make sure that the gas cap vent is functional.

Kenny G  

It would be useful to know the baseline of your setup.

You haven't mentioned the exhaust/muffler. Is it stock or something else? That's gonna affect the tuning.

Also do you remember which jets are in the carb and what height the needle is set to (position/size of the spacer)?

This is assuming you aren't the first owner.

Although you said it came on slowly and not as a result of your work, I still wonder if it is something in the diaphragm?  I'd look closely at it and make sure that it was all put back together properly. If you took the needle out of the diaphragm, do you know for certain that it was put back the exact same way and at the same level if you have an adjustable needle?  The little silver thingy down in the diaphragm should be "dimple down" with the two of the four holes that are NOT for screws visible open and aligned with the holes in the bottom of the plunger. If you get the silver piece flipped around you can put it back wrong blocking one of the holes.  

Also, check for any tears in the diaphragm and when it is out make sure that the slide is very clean in addition to the carb body. Even fingerprints can be a starting point for grease and stuff to stick to and cause a sticky slide.

Not saying that this is definitely the problem, but if you haven't changed jets at all and the float level is good, something somewhere is impeding fuel flow and a sticky slide not "sliding up" with the RMP of the engine would cause inadequate vacuum and limit the fuel being pulled into the engine, etc.

This link is not for our bikes, but a recent post I read when troubleshooting some carb issues of my own and it really helped me visualize "where" (in relation to throttle level) my issue likely was and where to start looking and testing things.

Good luck!
http://totalruckus.com/phpBB3/viewtopic.php?f=28&t=82639

Thanks for everyone's input.
Got it fixed today, it was the intake flange "O" ring.
Dried out and hard. The dealer can get me one in a week
I put a buna ring temporary, runs great!!