High idle while moving

[rerb]

Hi, I just finished piecing back together my b12 after rebuilding it for a turbo. It runs great, other than when I come to a stop the idle wavers around 3k for about 5 seconds before dropping to 1k. While riding it, If I pull the clutch in or put it in neutral, the idle will stay at 3-4k and won't drop down. I have the vent bowl breathers tucked in the notch of the airbox, and all vacuum tops capped except the one to the gas tank. Airbox is on with a k&n filter, and the exhaust is off a merge collector header without the turbo. Obviously the lack of exhaust leans it out a bit, but when accelerating it feels perfect. Could that be the culprit? Or are there any other carb ports than may cause this, I might've missed something while rebuilding them.

Also, choke cleaner finds no air leaks. Thanks.

[rerb]

Bit of more info, The bike actually idles better when one of the vacuum take offs is removed from the top of the carbs. I discovered this after one fell off. With it on, the bike will sometimes refuse to go down from 3k rpms until choked. Engine runs rough from anywhere to quarter throttle as well. 

I read that lower compression can cause a hanging idle, not too sure how, does that have any truth to it? Since CRE was lowered by busa pistons. This problem keeps on persisting. Thanks. 

[clivegto]

Hanging idel can be caused by carbs not been balanced but your problem sounds worse than that. 

[rerb]

On 5/7/2021 at 11:35 AM, clivegto said:

Hanging idel can be caused by carbs not been balanced but your problem sounds worse than that. 

I'm starting to think a diaphragm might've torn, or hasn't sealed right

[rerb]

Installed #40 pilots instead if #37.5. Ran better, but the problem still persisted. I bought a set of #45 jets, but now I'm thinking that may be too rich. But with the other symptoms I have a feeling it's pretty lean, anyone have experience with these jet sizes?