Triumph Thunderbird 650cc 1961

With a world-wide reputation for performance, stamina and complete dependability, the famous Triumph Thunderbird has for many years been first choice of the keen sidecar or hard-riding solo man. Now with a light alloy cylinder head, more powerful braking and many other new features it is one of the most attractive motorcycles available today.

In almost every part of the world you will find Triumph motorcycles in service with the police. What higher tribute could be paid to Triumph performance, reliability and lasting service than this? Many years of experience enable Triumph to supply the right model for every police duty designed for equipping with a wide range of specialised radio and other equipment.

The modern vertical twin engine was first introduced by Triumph and has long since become the accepted type for high performance motorcycles. Triumph engines are famed for their efficient design and robust construction, which ensures absolute reliability over long periods. The 650 c.c. type illustrated here is the engine used, with minor variations, in all Triumph models of this capacity. Note the twin high-level camshafts driven by gears, the tremendously rigid crankshaft and the light alloy head with large diameter inclined valves.

The inset sketch shows the plain distributor driving gear (as on 6T). On the main drawing the gear incorporates auto-advance for magneto (as on other 650 c.c. models).