Idle wont drop back down.

Just finished rebuilding my 77 kz650. Now just fine tuning how it runs.
I cleaned the carbs, put in the new jets, suggested for the 4into1 pipe, and k&N filter.
Then adjusted the float level.
Now it idles pretty well, and runs good under load.
But if it is idling nice at 1200-1500, and then I blip the throttle up to about 3K, it just stays at 3K. Even if I let the throttle back to idle.
If I put it into 1st, release the clutcha little in order to put a little load on. It will drop back to normal idle 1200 and stay.

But then blip it back up to 3K it just stays.
Is it running rich??
Maybe need to adjust air/fuel screws??
I checked the throttle return cable, and its fine. The throttle is closing back fine, Its just the rpms dont drop back
Any Ideas are greatly appreciated.
MJ

I would start with the idle air screws. Get the engine good and warm, and then set the idle at 1500. Adjust the air screws, one at a time, so that you obtain the highest idle speed, and then turn the air screw in 1/4 turn. Reset the idle to 1500 after you set each carb.

I suspect you will end up with your idle speed screw being set lower, which will help make the engine return to your preset idle speed immediately.

Sounds to me like you have an air leak between the carbs and the head. Try spraying some WD-40 on the carb connectors and see if the idle is affected.

KZCSI