The 1988 Polaris Indy 400 SKS is a snowmobile designed for entry-level to mid-range trail and mountain riding. Building on Polaris's long heritage in snowmobile manufacturing, the Indy series was known for its balanced performance and predictable handling. This model features a 2-stroke, liquid-cooled, twin-cylinder engine with a displacement of approximately 398cc, utilizing dual Mikuni carburetors and a CDI ignition system. Its Continuously Variable Transmission (CVT) with P85 primary and P90 secondary clutches provides a smooth and adaptable riding experience, making it a capable option for general snowmobiling. This comprehensive Factory Service Manual (FSM) provides complete service and repair information for the 1988 Polaris Indy 400 SKS. It covers all essential systems, including detailed engine diagnosis and overhaul, fuel system maintenance, ignition system troubleshooting, drive and suspension system service, braking system procedures, and electrical system diagnostics. The manual also includes routine maintenance schedules, component rebuild instructions, and guides for identifying special tool requirements. This resource is invaluable for owners, mechanics, and technicians seeking to maintain, diagnose, and repair the snowmobile, ensuring its optimal performance and longevity.