hi have been stunting for 3 years and my f4i has been a beast for the 2 ive owned it but *** i got better i noctice a lag in my bike.. WHen i start circling and going hard my bike loses power and has weak throttle response in slow circling..Ill hit the throttle and you can feel the bike lag..also from take off under 3k it lag when u try to take off quickly..
HELPPPP!! what could this be

 

When was your last tune up? have you ever cleaned your mass air flow, how about you fuel filter?

 

may need to sync your throttle body vaccume