I've never tracked a bike but have done cars it looks like from the video that you don't accelerate hard enough out of the corners. This is solved by getting on the gas earlier into the corneraround the halfway point. Remember the more speed you carry out of the corner the quicker you are in the straights. I was taught you brake before the corner and accelerate hard around and out of the corner. That is if you can hold the grip. When I ride twisties on my bike I brake hard before the corner and acclerate through it. I do have a hard time with sustaining enough grip to carry through the corners sometimes under super hard acceleration