1974 Yamaha DT250A / DT360A Factory Service Manual FSM (P/N 450-28197-20)

• Official Yamaha publication 450-28197-20
• Covers 1974 Yamaha DT250A and DT360A motorcycles, including detailed specifications for the 250cc and 360cc 2-stroke Torque Induction engine configurations
• Contains over 120 exploded-view diagrams, electrical schematics, and tolerance charts
• Provides the primary technical reference for the launch build of both displacement variants

Technical Documentation and System Overview

The official factory publication structures service data across nine specialized chapters. It begins with machine identification, general specifications, and a breakdown of required service tools. From there, the documentation shifts into engine tuning and maintenance schedules tailored for high-frequency trail use. Deep-dive technical data covers the clutch, 5-speed transmission, and the Autolube system. You will find specific carburetor settings for the Mikuni VM28SS and VM30SS units. Electrical sections isolate the exact differences between the DT250A magneto ignition and the DT360A Capacitor Discharge Ignition (CDI) systems.

Additional sections provide precise factory tolerances for engine rebuilds. Cylinder head torque sits at 2.1 to 2.5 kg-m. Transmission fluid capacity is noted at 1,000 cc for the 250cc model and 1,200 cc for the 360. The manual lists definitive clearance limits for piston rings, clutch friction plates, and transmission shaft end play to maximize component longevity. Cylinder bore taper limits are strictly set at 0.05 mm. Out-of-round tolerances max out at 0.01 mm. Spark plug torque requires 230 to 250 in-lbs to ensure secure heat transfer during high-performance operation. Because incorrect torque or clearance specifications can lead to catastrophic engine failure or rider injury, always verify your equipment against these published OEM limits before starting the engine.