My 2001 YZ 426 is got a problem...finally! When im in 5th gear, probably running over 5-6 thousand RPM and i get on it really hard it feels like the clutch is slipping or something...it does it about once a second and a half and only for a fraction of a second and only on hard packed dirt. It feels like your lightly tapping the clutch about once a second or so...but it doesnt do it when the RPMS are low or in any other gear than 5th. When the soil is loose you dont notice it. I thought at first maybe my 5th gear was going out but you would think it would do it at a faster rate and not so slow as im sure those gears are spinning pretty fast. All the other gears are perfectly fine and it shifts great...just 5th. Any ideas???