Motorcycle 520 Front Rear Sprocket Kits Set For Yamaha WR250X WR250R WR250F Fit For Yamaha WR250X 2008-2015 WR250R 2008-2020 WR250F 2001-2006 2010-2014 dirt bikes with standard 520 pitch transmission system CNC machined sprockets follow OEM tooth profile mounting hole layout for direct bolt on installation without Adopts treated with strong abrasion resistance to withstand rough off road terrain friction Optimized tooth curve lowers chain vibration running noise, ensures steady power output for cross country riding Complete front rear sprocket set meets daily offroad worn drive gear replacement needs