1977-1982 Honda NC50 Express / NA50 Express II Service Manual

Honda NC50 and NA50 Express Service Manual

• Covers 1977–1982 Honda NC50 and 1979–1981 Honda NA50 Express mopeds, documenting 49cc 2-stroke engine, electrical, and transmission specifications
• Original OEM publication, date of issue November 1980, inclusive of 1979–1982 model year addendums
• Contains 40 detailed exploded-view diagrams and 35 technical specification tables
• Downloads to your account within seconds of checkout
• Your order stays downloadable from your account for life
• OCR text layer lets you jump to a torque spec by keyword
• Suitable for printing individual sections for shop-floor use
• This 1980 publication acts as the master technical reference for the entire 1977–1982 Honda NC50 and NA50 production run, incorporating all factory-issued servicing supplements

Mechanical and Electrical Documentation

This Honda service manual provides technical data and disassembly sequences for the NC50 and NA50 Express series. The text describes the 2-stroke engine fundamentals, including reed valve arrangement, loop-type scavenging, and carburetor piston-type circuit functionality. It documents the starting mechanism, where the starter spring stores energy, and the wet centrifugal clutch engagement points for power transmission. The manual details the lubrication system, specifically the crankshaft-driven plunger pump and oil flow path, along with frame-specific procedures for front forks, rear suspension, and wheel hub maintenance. It is an indispensable guide for owners performing routine maintenance or teardown diagnostics on their Honda NC50 and NA50 series mopeds.

Technical Preview and Specifications

Specifications cover engine clearances, piston-to-cylinder tolerances, and torque values for engine and frame fasteners. Cylinder head bolt torque values are documented at 90–120 kg-cm, while flywheel generator nuts are tightened to 300–350 kg-cm. Piston ring end gap is listed at 0.15–0.35 mm in the service data section. The manual provides reference values for the battery charging system, detailing a charging current of 0.2A for 12–13 hours. Electrical wiring diagrams show the lighting and ignition circuits for both the base NC50 and the NA50 Express II. Understanding factory workshop documentation for vintage mopeds is essential when performing service. Note: This page is a contents overview for the manual. It does not provide repair or diagnostic instructions. An official 100-page Honda OEM shop manual covering the 1977–1982 NC50 and NA50 Express series, documenting engine, chassis, electrical, and fuel-delivery specifications for the base units and all associated model-year addendums.

Document Reference: Honda Motor Co., Ltd., Service Publications Office, November 1980, 1981 print