Yamaha IT490 IT250 1984 Owner's Service Manual (P/N 29V-28199-70)

• Official Yamaha publication 29V-28199-70, first edition published in July 1983
• Covers the 29V and 45-series enduro models, detailing the 487 cc and 246 cc two-stroke powerplants
• Contains 80 pages of technical diagrams, exploded parts views, and electrical wiring schematics
• Serves as the original factory baseline document for all 1984 production units

Document Overview and Technical Data

Mechanics and vintage enthusiasts working on the 1984 Yamaha IT490 and IT250 require accurate operational parameters to maintain these classic enduro machines. This owner's service publication outlines the exact factory specifications for both the 490 cc and 250 cc variants. You will find dedicated chapters detailing engine assemblies, chassis hardware, and the complete electrical system. Furthermore, the appendix includes a structured troubleshooting guide that isolates common ignition, compression, and fuel delivery issues.

Specification Highlights

Hitting the correct factory tolerances is critical when servicing older two-stroke engines. The manual provides essential maintenance data, noting a piston clearance of 0.070–0.075 mm for the IT490. It documents the 0.75 L transmission oil capacity required for routine fluid changes. Ignition timing is another vital metric clearly charted, specified at 2.00 mm B.T.D.C. in the engine tables. The documentation also lists comprehensive torque values, such as the 75 Nm requirement for the primary drive gear nut. Because working on vintage motorcycles involves inherent physical risks and potential equipment damage, always verify mechanical conditions and consult a certified technician before attempting major repairs. Please note that this page solely reviews the contents of the original OEM literature and does not provide direct repair or diagnostic instructions.