I went riding yesterday and my 97 KDX220 would not shift out of first gear. I had been riding for over 2 hours with not problems and all of a sudden I could not shift from 1st. Nothing unusual happened and the shifter operates up and down but nothing happens. I loaded the bike up and came home. I have never had the motor apart or the clutch side case off. I looked in the Kawasaki service manual but thought I might ask for your assistance before starting to work on the bike. Where should I start? Thank you for your help. Jim