New Genuine Yamaha YZ125 GYTR Complete Engine Performance Kit - The GYTR YZ125 Performance Kit is a comprehensive bolt-on engine kit developed to increase power and improve throttle response while maintaining strict Yamaha reliability standards. Kit includes all of the following: - GYTR CNC Ported Cylinder - GYTR Two Piece Head - GYTR Tuned CDI - GYTR High Compression Piston Assembly (two per kit) - GYTR Exhaust Valves - GYTR Jetting Kit - V Force 3 Reed Valve - GYTR Silencer - GYTR Pipe - GYTR Carbon Fiber Ignition Cover - Titanium / steel exhaust system - Yamaha recommended jetting specification ***Note: Requires high-octane race gas or 91 octane or higher pump fuel ***