This comprehensive workshop service repair manual provides detailed instructions and illustrations for maintaining and repairing your Triumph 6T Thunderbird, TR6 Trophy, and T120 Bonneville 120 motorcycles manufactured between 1963 and 1970. It covers the 649 cc 2-cylinder OHV engine and includes sections on general information, lubrication system, engine system, air cleaner system, carburetor system, exhaust system, timing system, oil pump system, transmission, gearbox system, clutch plates, fuel tank and panels, frame and attachment, wheels and tires, brake system, telescopic fork, electrical system, ignition system, lighting system, service tools, conversion charts, and wiring diagrams. This manual is an invaluable resource for both novice and experienced mechanics, providing step-by-step instructions and detailed diagrams to guide you through every repair and maintenance procedure.

The TRIUMPH 6T Thunderbird, TR6 Trophy, and T120 Bonneville motorcycles, produced between 1963 and 1970, represent a pivotal period in the history of the iconic British motorcycle manufacturer. These models, often referred to as the "pre-unit" Triumphs due to their separate engine and gearbox, were known for their powerful performance, distinctive styling, and enduring reliability. The 6T Thunderbird, the largest capacity model in the lineup, was designed for comfort and touring, showcasing a spacious saddle and a relaxed riding position. The TR6 Trophy, a versatile option, balanced performance and practicality with its lightweight frame and efficient engine. The T120 Bonneville, a true icon, cemented its place in motorcycling history as a high-performance, exciting machine, epitomizing the spirit of the era. These Triumph models were powered by a 650cc parallel-twin engine, renowned for its robust construction and smooth, reliable operation. The engine featured a cast-iron cylinder block and aluminum cylinder heads, delivering a healthy power output for its time. The bikes were equipped with a four-speed gearbox, a traditional telescopic front fork, and a swing-arm rear suspension, providing a balanced ride and handling characteristics well-suited to both city streets and open roads. The iconic "pre-unit" design, with a separate engine and gearbox, offered ease of maintenance and repair, a feature that contributed to their enduring popularity amongst enthusiasts. Today, these Triumph classics continue to be cherished by collectors and riders alike, representing a golden era of British motorcycle engineering and design.