High Rev Problems

I have an 81 yamaha xj550r Seca that I have been rebuilding since last August. I have everything just about worked out except for one thing. I just rebuilt the crabs and tuned them so it has just started to idle fine without it slowly dying out. But now when I pull on the throttle it revs up to about 4000 rpms and it just stays there and will not come back down till I use the idle screw to bring it back down. I just rebuilt the carbs and the throttle is not sticking. I tried spraying the carb boots with starter fluid and that made it rev up again without me touching the throttle but im not sure if the starter fluid is just getting into the carbs when I spray it or if that could be the problem. Has anyone had any problems with this or have any idea of what could be going on?

 

The starter fluid spray corresponding with rev increase strongly suggests an air leak.
Are you talking about the boots between the engine and carbs? Did you replace those gaskets?
Did you go to Church?
http://xjbikes.com/forums/threads/in-the-church-of-clean.14692/