This manual covers the Yamaha Enticer snowmobiles, specifically the ET340 and ET400 models produced between 1986 and 1990. These reliable snowmobiles, known for their practicality and comfort, were manufactured by Yamaha Motor Company during a dynamic era in snowmobile technology. The Enticer series was designed for trail riding enthusiasts, offering a blend of performance and user-friendliness. This guide provides in-depth information for maintaining and repairing these classic machines, ensuring their continued operation for years to come. The purpose of this comprehensive service manual is to provide owners, mechanics, and technicians with the necessary information for the upkeep and repair of the 1986-1990 Yamaha Enticer ET340 and ET400 snowmobiles. It details essential maintenance procedures, including routine checks, lubrication, and component adjustments. Furthermore, the manual offers extensive guidance on troubleshooting common issues and performing repairs across various systems, such as the engine, fuel system, drivetrain, electrical components, suspension, and steering. Detailed technical specifications and diagnostic information are included to facilitate accurate assessments and effective repairs.