Boyesen RAD-34J RAD Valve Fits: Yamaha YZ250 2005-2015 Integrated into the seamless interior chamber are 4-way aerodynamic directional dividers that distribute the angled charge evenly without flow loss Integrated into the seamless interior chamber are 4-way aerodynamic directional dividers that distribute the angled charge evenly without flow loss Optimized air intake system provides superior efficiency, peak horsepower gains, and acceleration for YOUR specific model machine, tailor made to that model, year and displacement Increases peak horsepower through Boyesens own innovations: Aerodynamic Surface Optimization, Model-Specific Reed Petal Tensioning, Material Fuel Resistance, and Multi-Stage Reed Timing