I'm working on a buddy's 2009 450 xcf. I checked the valve clearance and I'm confused why they out of spec on the loose side. I'd figured they would get tighter overtime but that's definitely not the case. so here is what I'm getting LE RE .011. .011 LI. RI .009. .010 Is this normal on these engines for the clearence to wear loose? is it too far out of spec to try shim? Any imput is greatly appreciated.