My '07 yz450f almost always takes at least 5-6 hard kicks to get it started and I'm getting a sick of it. My '98 yz400f would always start first or second kick for me so why is this thing so hard to start? The valves are within spec and all the jets are clean. I also put in a brand new spark plug. Should I try a bigger starter jet? If so what size should I try? What size is the stock starter jet?