1979-1992 Yamaha QT50J, MA50 Yamahopper Service Manual

Yamaha QT50J and MA50 Yamahopper Service Documentation

• Covers 1979–1992 Yamaha QT50J and MA50 Yamahopper moped variants, detailing mechanical inspections, engine overhaul, and chassis maintenance requirements.
• Third-party publication by UserFriendlyCDs, copyright 2006, documenting the 1979 first edition service specifications.
• Contains 47 pages of technical diagrams, color codes, exploded-view engine assemblies, and torque specification reference tables.
• File link appears in your order confirmation straight away.
• Indexed PDF search covers every chapter and appendix.
• Laid out for standard letter and A4 printing.
• This 2006 reissue of the original 1979 manual serves as the primary technical documentation for the QT50 series, including specific procedures for the Autolube oil pump system and reed valve assembly.

Mechanical Scope and Maintenance

This manual provides detailed technical information for the Yamaha QT50J and MA50 Yamahopper, focusing on engine overhaul and periodic inspection. Each major system, including the 49cc 2-stroke engine, carburetion, transmission, and chassis components, is documented for service technicians. The content includes guidance on air cleaner maintenance, oil pump bleeding, and ignition timing verification, ensuring the 6V electrical system and autolube pump remain within specifications. The manual also outlines daily pre-operation checks to verify brake performance, tire pressure, and fastener security for the safety of the rider.

Specifications and Reference Values

Technical data includes specific tolerances for engine components and tightening values for critical fasteners. The cylinder head nut torque is specified at 10 Nm in the engine assembly data. The transmission oil capacity is 0.3 liters, while total fuel tank volume is documented at 2.3 liters. The front tire pressure is listed at 18 psi, with the rear tire pressure at 28 psi. For electrical diagnostics, the manual provides pinout and component wiring diagrams for the 6V charging system. Reference only — always consult a certified technician before performing service on this equipment. A 49-page technical workshop manual covering the 1979–1992 Yamaha QT50J and MA50 Yamahopper, documenting engine, chassis, and electrical specifications for the Yamahopper moped platform.