This manual covers the AJS & Matchless Lightweight and Heavyweight Motorcycles produced between 1957 and 1966. These British-manufactured motorcycles, known for their robust engineering and racing heritage, include a wide range of models such as the G2, G2S, G80, and 18S series. They are characterized by their single-cylinder engines, ranging from 250 c.c. to 600 c.c., utilizing both 2-stroke and 4-stroke designs with Overhead Valve configurations for many 4-strokes. The motorcycles feature telescopic front forks, swingarm rear suspension with twin shock absorbers, and drum brakes. This manual provides comprehensive information for maintaining and repairing these classic machines, empowering owners and mechanics alike. This factory service repair manual is designed to assist DIY enthusiasts and professional mechanics with the service, repair, maintenance, and overhaul of AJS & Matchless motorcycles from 1957-1966. It offers detailed step-by-step instructions for a vast array of procedures, including engine design changes, lubrication, gearbox and clutch operations, suspension component servicing, brake adjustments, and electrical system troubleshooting for both Wipac and Lucas components. The manual also includes detailed wiring diagrams, technical data, and carburetor servicing and tuning procedures, covering common wear items and typical failures to ensure the longevity and optimal performance of these vintage motorcycles.