1963 Triumph 6T Thunderbird

Unit Construction.

1963, Triumph introduces the 650cc 'Unit Construction' Turner designed engine, which incorporated the engine, primary and transmision in one housing. The crankcase split vertically into two halves, inner primary case going with the left crankcase half, and the transmission housing going with the right. The result was an engine that was lighter, stronger, more modern and cleaner than the pre-unit engine it replaced. And it made it possible to pull even more power out as the 1960s progressed. With all this, the age of the pre-unit Triumph was over, the 500 twin already gone unit-construction in 1959.

 

Unit construction brought with it many benefits. They were less expensive to manufacture, assemble and were easier to maintain. This new package saved 30lbs compared to the pre-unit engine, primary, gearbox and mounting plates of earlier design.

Also for 1963, a whole new frame with a single front downtube replaced the 'flexy' duplex frame (1960-62), virtually eliminating all the handling problems overnight. From this point on, Triumph Motorcycles would gain a reputation as some of the best-handling motorcycles worldwide.

We aquired this rare motorcycle pictured here and proceeded with a mild restoration. It is a matching numbers bike and quite original for it's age. Note the main rider footrests which bolt onto the bottom of the frame rather than the rear engine mounts as of later models. This was done only for 1963 models!
As expected of Triumph motorcycles from this era, the 6T looks great, performs well and is a pleasure to ride.