It has stumped most of the riders that were there. My son's new 2006 KX250F, that he had only 6 hours of ride time in, snapped the front sprocket in half while riding it. We have the bike down at the dealer and they are stumped as well, they are going to bat for us at Corporate Kawasaki, who has requested to see the sprocket and chain, so that has been sent to Kawasaki for their techs to inspect the sprocket. Curious if anyone out there has heard of or knows of this happening to any other 250's. Other than this mystery of a sprocket, my son has long awaited to ride his 250 and loved every minute of the six hours he rode it.