1978-1982 Yamaha IT250 / IT465H Owner's Service Manual (P/N 5L4-28199-20)

• Covers 1978–1982 Yamaha IT250 and IT465H enduro motorcycles, including model-specific engine, chassis, and suspension tuning configurations for the 5L4 and 5L5 series builds.
• Official 73-page Yamaha OEM publication (P/N 5L4-28199-20, first edition December 1980) referencing additional codes 29V-28199-70 and 51.4-23199-20.
• Includes 16 technical exploded-view diagrams, two complete wiring schematics, and consolidated torque specification tables.
• Provides the baseline service data for the IT-series evolution, documenting unique specifications for both the 250cc and 465cc engine variants.

Manual Content Summary

This factory publication delivers the specialized maintenance data required to keep the IT250 and IT465H enduro series race-ready. Off-road competition demands strict routine adjustment schedules, and this text outlines the exact factory procedures for pre-operation safety checks, essential engine service intervals, and fundamental machine identification. Inside, the chapters break down complex assemblies for the workshop floor. You will find complete teardown overviews for internal transmission components, carburetor tuning, and the air induction system. It also details critical steering head maintenance and drive chain alignment. The focus throughout is on sustaining mechanical integrity and optimal power delivery on the trail.

Specification and Technical Preview

Accurate assembly relies on precise factory numbers. This documentation lists critical reference values directly from Yamaha, including exact carburetor float heights, ignition timing, and piston ring end gaps. Mechanics can reference detailed tightening torque tables featuring both Nm and m-kg values for the engine, chassis, and suspension components to prevent overtightening. Tracking down electrical faults? The guide provides the baseline electrical reference values for CDI components, detailing pulser coil and stator resistance for efficient diagnostic troubleshooting.

Always cross-reference these factory specifications and adhere strictly to standard workshop safety protocols before initiating any structural or engine teardown. The data provided in this reference material serves as the definitive guide for qualified hands-on service work.