Yoshimura YZ250F 19-23 / YZ250FX 20-23 / WR250F 20-23 RS-4 Stainless Slip-On Exhaust, W/ Aluminum MufflerYoshimura YZ250F 19 23 YZ250FX 20 23 WR250F 20 23 RS 4 Stainless Slip On Exhaust, W Aluminum Muffler The Yamaha YZ250F is an all new machine for the Blue Cru and by the looks of it, the refinements to this bike will continue to drive the 250cc class progression forward. Yoshimura quickly went into development on this very important model, even involving the Australian Factory Serco Yamaha Supercross Motocross Race Team for feed back on making the new