The 1987 Polaris Indy 400 is a snowmobile designed for recreational trail riding and light utility tasks, representing a balance of performance and efficiency. This model typically features a 2-stroke, twin-cylinder engine with a displacement of approximately 398cc to 430cc, likely fan-cooled, and is equipped with Polaris's P-85 primary clutch and a secondary clutch for continuously variable transmission (CVT) operation. Its engineering quality and reliability are hallmarks of Polaris's established reputation in the snowmobile industry during the 1980s, a period when the Indy series was highly successful. The Indy 400 competed in a popular class, offering dependable performance for enthusiasts. This service repair manual provides comprehensive factory coverage for the 1987 Polaris Indy 400 snowmobile. It details essential maintenance procedures, including engine service and overhaul, fuel system maintenance, ignition system diagnostics, drive system and clutch service, suspension and steering component care, brake system maintenance, and electrical system troubleshooting. The manual also covers routine tasks, troubleshooting guides, and specific repair techniques, offering detailed instructions, diagrams, and critical specifications. Its purpose is to assist owners, mechanics, and technicians in maintaining, diagnosing, and repairing the snowmobile to ensure optimal performance and longevity.