Ok i was out doing some trail riding this weekend and for most of the weekend it ran great,but all of a sudden it had no power band.I just figured it was a fouled plug so i changed the plugs twice and no change.It revs clean in neutral and starts first kick,the new top end is 5 hours old and compression is still the same as the last time i checked it perfect.The clutch does`nt seem to be slipping at all,every thing is normal except no power band.It can`t be jetting cause it ran perfect almost all weekend and the weather did`nt change at all.Tors was removed so that can`t be it either.I did refuel with new fuel that may have been mixed a little richer than i mixed the first batch,and i was riding in a little mud,but my airfilter is clean and i`ve never had a problem with running my fuel a litte rich .The plugs where a little black but not wet but they where all weekend.Im stumped,what do you guys think?