Purchased a 450 this spring to race HS. Doing some practice on my woods HS course here at home. I'm trying to get on the gas faster out of the corners and having trouble with the bike stalling. I'm sure of what jetting it has. It had a stock silencer and air box. I have installed an FMF silencer and Power Now power valve. I'm running 93-ethanol-free gas. It does have the fuel screw extension. Air filter looks fine also. Would installing a jet kit help? How can I tell if it already has a jet kit?