My wife rides a KX85,hasnt lost that screw.But now I know to check it,Thanks.Any thing the kids have done to there 85's that you suggest,like a pipe ect?Her bike has a fly wheel weight and a moose spacer,makes it a great beginers bike.I was thinking of her riding a little XR,but she wanted the KX.The XR's were to heavy she said after trying them.