My buddy has a 2010 yz 450F and I have a 2012 YZ 450F. We both have stock gearing, I have a stock motor and as far as we know he has a stock motor too. Why does his bike spank my bike so badly?? When Im 5th gear tapped and hes 5th gear tapped, he literally just pulls away from me like a freight train. Whats different between the bikes?? All I keep reading is how restrictive my stock exhuast is. Could that be the problem?? Please help! Sick of hearing about how much slower my bike is lol. But mine feels like it hits down lower harder than his does..