I have a 2002 kx250 and I was riding it on the weekend and it is shifting realy bad.sometimes when i went to shift down it would feel like I was in first because the shifter wouldn't go down but realy I was in 3rd.or 2nd then when I was accelerating i would shift up and it would feel like it "clicked in"but then it would still be in the same gear.what should I do?I just changed oild to belray gear save 75w(I think)any ways lots of people recomended it as a good oil.it wasn't foing this last week please help.thanx