1976-1979 Yamaha RD250, RD400 Supplementary Service & Repair Manual (P/N 2R8-28197-80)

• Covers 1976–1979 Yamaha RD250 and RD400 models, including the C-series variants with documented serial number ranges
• Official Yamaha OEM publication 2R8-28197-80, first edition printed in December 1977
• Contains 50 pages of pure technical specifications, featuring 15 detailed torque tables, ignition timing procedures, and complete wiring schematics
• Specialized exploded-view diagrams highlight the Autolube system, front fork assembly, and engine mounting hardware
• Cross-references specific factory tool numbers for flywheel holding and pulling operations to streamline bench work
• Documents essential technical updates and specification changes for the entire production run

Content Overview and Documentation

This supplementary service manual details the exact revisions required for the 1976–1979 model cycle. Working as a necessary companion to the base workshop manual, it outlines updated specifications for these classic two-stroke machines. You get precise factory adjustment targets for the torque-induction engine. The manual specifically focuses on dialing in the Autolube pump, ignition timing, and carburetor synchronization settings to ensure peak running condition.

Technical Data Preview

Section coverage spans engine maintenance, chassis inspection, and detailed electrical system testing. For instance, front fork oil capacity is strictly documented at 163.5 ± 4 cc per side. Total transmission oil capacity sits at 1.7 liters, though a standard drain-and-fill requires exactly 1.5 liters. You will find cylinder head nut torque specified at 1.9–2.1 m-kg. Ignition timing differs slightly between models; the RD250 runs at 1.6 mm B.T.D.C., while the RD400 is set to 2.0 mm B.T.D.C. The electrical data section also calls out the C.D.I. magneto rotor puller thread size as M27 x P1.0. Note that modifying or adjusting engine components carries inherent mechanical risks. The service data provided here serves as a reference overview, and any hands-on shop work should always rely on reviewing the complete OEM documentation and standard workshop safety practices.