The GYTR Ported Cylinder Head Assembly comes fully assembled and ready to install with no costly core changes or deposits or exchange programs that can add downtime. CNC milling helps eliminate the variances that hand porting can produce. The head was developed on the flow bench in conjunction with dyno and track testing to ensure the ultimate in performance and durability. GYTR Performance Camshaft Kit is included, as well as stock valve train and cam gears for durability and easy maintenance. GYTR Head Assemblies are used by Yamaha SX / MX and ATV Race Teams. This accessory is restricted to closed-course use.