I have about 250 hours on my YZ450. I was riding pretty hard in deep dry sand yesterday. I missed a shift and after that it felt like the shifting became notchy and took more effort to engage the next gear. All the gears feel the same and I have no problem finding neutral. It does not pop out of gear. I don't know if the problem started because of the missed shift, or I missed the shift because the shifting became harder. This is all in shifting without the clutch, up or down a gear. I'm running Rotella T 15w40, about 2 hours on this oil change. The clutch has about 50 hours on all new plates and springs. My first though is to change the oil to Mobile 1 (what I usually run) and see how it feels. Any other ideas on where to look? Bent shift shaft or bent shift forks?