Motorcycle Repair: 2stroke problem, air leak, carby

Question
I checked everything on my cr250 2stroke 01 model, i have even rebuilt the motor to the manuals specs.carby looks fine .
I have a few symtoms that are eveident but i cannot find a answer to my problems.
symtoms are.>
1.poor idle.
2.when reved the idle doesnt return as fast as it used to.
3.when reved hard and the throttle returned to closed position the motor chugs its way slowly back to idle.
Total lack of bottom end power that results in a agressive  powerban that is very short(high rpm)or atleast shorter than it was when it was running fine?
If you could just tell me what is causing these symtoms?... thank you  

Answer
Hi Corey,

I suspect a vacuum or intake air leak. However, it's diffficult to accurately diagnose the symptoms without inspecting the engine and performing a few tests.

Follow the service manual's troubleshooting procedures.

Respectfully,
Mark Shively