My buddy just bought a '97 KDX220 that has had very little wear and only a few changes from stock. When I tried it on the tight trails I noticed that it was geared way higher than my '00 220 (I'm running 13 to 48 sprockets). When we checked his sprockets they were 12 to 47 which should make his bike lower geared than mine. What gives? Were changes made between model years '97 and '00 which would explain this?