This manual covers the YFM660F Grizzly660 and YFM660R Raptor660 models produced between 2001 and 2008. These ATVs are renowned for their powerful 660cc liquid-cooled engines, with the Grizzly offering an Ultramatic automatic transmission and 4WD for utility and trail riding, and the Raptor featuring a manual transmission for sport riding performance. Both models are recognized for their robust engineering, independent suspension systems, and commitment to durability and rider capability, earning them acclaim in their respective segments for performance and innovation. This comprehensive workshop repair service manual provides detailed instructions for maintenance, repair, and overhaul of your ATV. It covers all essential systems, including engine mechanicals, fuel, ignition, drivetrain, transmission (both automatic Ultramatic and manual 5-speed), suspension, brakes, and electrical systems. The manual includes routine maintenance schedules, troubleshooting guides for common issues, detailed engine and transmission rebuild procedures, electrical diagnostics, and all necessary torque specifications. Its thorough content is designed to assist owners, mechanics, and technicians in keeping these high-performance ATVs in optimal working condition.