The 1933 Velocette KTT was the fifth year of the KTT line that would run until 1949. Based on Velocette’s very successful 350 KSS, which won the Isle of Man TT in 1926 (10 minutes ahead of the next bike), the KTT was a very advanced machine. The KTT went on to become one of the most successful road race motorcycles of its time, racking up many international titles in its long career. The entire “K-series” were designed for racing, although Velocette wasted no time in cashing in on their racing success by building popular street bikes. All K-series Velocettes had a single-overhead camshaft (SOHC) driven by a vertical shaft with elaborate bevel gears on each end. When set up right, it was a brilliant and effective system, but they were extremely laborious to put together on the assembly line and required the experienced hands of a craftsman. Not the kind of thing you want in high-volume motorcycle production. This bike represents a typical example of a very long, and worthy line of KTTs that ran until 1949. A very long run indeed.
1933 Velocette KTT Engine
The Velocette KTT has earned many distinctions, not the least of which being the first motorcycle ever to employ a positive-stop sequential foot-shifted gearbox. We don’t even think about it today, but that ‘one-down, four-up’ move you’ve done a million times didn’t exist prior to this bike. Above, you can see that long housing rising up and back from the crankshaft, that’s covering the chain that drives the Lucas magneto. It’s also a great shot of the shaft-drive for the OHC. Notice the exposed ‘hairpin’ valve springs. Yet, the KTT was considered to be ahead of its time in 1933. The metallurgy of the day wasn’t advanced enough at the time to produce reliable coil spring that could take the long-term punishment of road racing. Velocette’s approach was not unique, others were experimenting with hairpin valve springs. Velocette just did it better, that’s all.