I recently rebuilt my 2007 yz450f. Had the head redone with stainless valves, springs and polished up. I also installed a High compression piston 13.6 : 1 and new timing chain. Starts first or second kick but the power feels mushy and flat. Im thinking the power should be crispy and pull super hard. I have a 165 main 48pj and stock needle in the stock position, 3rd. Stock exhaust back on. Im under 0-2500 feet in Northern Cali. Im thinking of trying a 170mj and maybe the needle in the 4th clip?