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 Velocette - 400 KDT dirt-track
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Velocette KDT dirt-track motocyclette motorrad motorcycle vintage classic classique scooter roller moto scooter
Photo ou archives : F-M. Dumas

Capacity : 400
Model : KDT dirt-track
Production : 1930 -
Category : (Off-Road) Speedway & other


400cc KDT Dirt Track ·1930

A racing rarity

The KDT was one of the rarest racing Velocettes. Only 22 were built by Veloce Ltd, and unsold stock was converted back into the KTT model from which the KDT had been derived.

Violent Acceleration

This exceptional Velocette, designed for dirt-track racing, used the famous overhead camshaft engine of the KTT Mk I with the bore increased from 74 to 80mm to bring the displacement to 407cc. In order to retain the original KTT cylinder head, it was necessary to use a special cylinder head joint with two superimposed bore diameters. The threespeed KTT gearbox was fixed in second, and an enormous 72-tooth sprocket gave the ultra-short final drive ratio necessary for the violent accelerations that were characteristic of this specialized sport.

Inspired by the Harley Peashooter

The braced short-travel telescopic front fork with its single, central spring was strongly inspired by that of the famous HarleyDavidson Peashooter speedway bike, and the frame was built for strength. Its open-cradle structure was built with two parallel tubes at the front and double tubes to make the rear wheel spindle mounting absolutely rigid. As for speedway racing, the 23 inch front wheel had no brake and, so the rider could brace himself into the saddle and control his machine in the long broadsides around the dirt oval, the right side of the machine was fitted with a bracket for the rider's knee.


Engine: 407cc (80x81mm) air-cooled singlecylinder four-stroke

Power Rating: maximum output developed @ 7000 rpm

Valves: shaft-driven overhead-camshaft in 10.25:1 compression bronze head

Fuel System: Amal twin float chamber carburetor tuned for methanol

Transmission: 3-speed Oocked in second), chain final drive

Suspension: girder forks (front); rigid (rear)

Brakes: drum (rear)

Wheels: 2.75x23 inch (front); 3.00x22 inch (rear)


Of 22 KDTs built, just five motors and this unique complete machine survive. The owner took 12 years to find all the parts necessary to restore it!


Le fichier Moto Passion réalisé par François-Marie Dumas réunit près de deux mille photos accompagnées d'un historique très complet des machines présentées.
Il sera progressivement mis à jour ici et toute information complémentaire est la bienvenue sur info@moto-collection.org.

Cette documentation unique, qui constitue sans doute l'encyclopédie la plus exhaustive jamais écrite sur l'histoire de la moto, a été réalisée avec l'assistance de nombreux spécialistes dont principalement Didier Ganneau, Christophe Gaime, Mick Woollett, Jean Goyard, Bernard Salvat, Christian Rey, Yves Campion, Helmut Krackowizer, Michael Dregni, Michel Montange, etc. que je remercie ici.

Disponible sur demande :
- Les fiches originales sur papier
- Les photos et archives signées de mon nom en haute définition ou les documents originaux.
Me contacter sur info@moto-collection.org pour les conditions et droits d'utilisation.