The 2005 Arctic Cat T660 Turbo ST is a performance-oriented Sport Touring snowmobile, distinguished by its powerful turbocharged 660cc Suzuki engine, offering robust performance for its class. Built with Arctic Cat's legacy of innovation, this model is designed for riders seeking both capability and comfort on varied terrain. Its engineering prioritizes reliability and a dynamic riding experience, making it a notable entry in the competitive snowmobile market of its era. This factory service manual provides comprehensive guidance for owners and technicians on the maintenance and repair of the 2005 Arctic Cat T660 Turbo ST. It covers all essential systems, including the engine, fuel, ignition, clutch, drivetrain, suspension, steering, brakes, and electrical systems. Detailed procedures for routine maintenance, scheduled servicing, troubleshooting, and in-depth repairs are included, along with technical specifications and electrical schematics, empowering users to ensure optimal performance and longevity of their snowmobile.