PETER BUTTERWORTH astride his 1935 KTT MK V at the Pukekohe Classic event in 2012 is racing what is undoubtedly one of the great British sporting motorcycles, the Velocette KTT (Kamshaft Tourist Trophy) enjoyed an illustrious career spanning three decades. The KTT series first become available as a road machine at the end of 1928 when two MK I’s were built. Production of the successful new model accelerated in 1929 when 178 were produced.
MK I–MK IV, 1928–34
As the name implies, the appeal of the KTT was that it was a very successful production racer offered to the public in a road going version. The KTT model series all benefited from the experience gained by the successful
Velocette works team, the MKI being in effect a replica of the works machines that had secured Velocette’s second TT win in the 1928 Junior race. The new model was powered by an overhead cam single cylinder engine displacing 348cc with a bore and stroke of 74 x 81 mm that could be distinguished from the road going models in the range by the external stiffening webs employed on the crankcase. Lighter, steel flywheels were employed and a hotter camshaft was fitted.
The works paid a great deal of attention to strengthening the valve train to prevent breakages and a revised cylinder head was fitted. Drive was taken to a three speed gearbox, similar to that used by the rest of the Velocette range but fitted with a set of close ratio gears, via a primary chain.
The well balanced rigid frame was equipped with a set of braced Webb girder forks, a design feature peculiar to the KTT. The MkII model ran in this form with only detail alterations until 1932 when the MK IV was introduced. The Mk IV was
fitted as standard with the new positive stop four speed gearbox which had previously been available as an option and a new cylinder head, still cast in iron, was employed, which offered improved combustion characteristics.
MK V–VII, 1935–37
1935 saw the introduction of the MK V which brought in a totally revised chassis employing a full cradle frame and a redesigned engine. The MK V remained in production until 1936.
No KTT model was listed officially in 1937, but 1938 witnessed the introduction of a new KTT, the MK VII. The new version had a massively finned alloy head and barrel and new front, girder type forks.
The MK VII remained in the catalogue for a season before being replaced by the definitive 1938 KTT MK VIII. The MK VIII, which would, with a break for the Second World War, remain in production until 1950.