Just curious what you think.
Im really wondering what the sound is when i let off the throttle and it goes VOOM-VOOM-VOOM-VOOM really fast.
I couldn't tell anything from your video other than you cut the end of you tailpipe off as I dosed off during that video of your front wheel while riding ;-}
Check your throttle.
This is easy.
Open the throttle all the way and then let go, it should snap back with an audible 'click'.