Speedway Workshop

Today in Motorcycle History

The Excelsior Mk1

The Excelsior Motorcycle Company was building speedway frames as far back as 1934, when they were approached by the J.A.P company to build a frame of their own design. Based on a Rudge style of frame, this early model was easily distinguishable being painted a dull red which earned it its nickname of the "Fire Engine".

LEFT: The Early Excelsior JAP.

Radical changes were brought about when Excelsior were chosen to build the famous Grosskreutz frames and brought about the style of frame that Excelsior were best known for.

Below are the abridged specifications for the MK1 Excelsior

Engine: Fuel Tank:
500cc JAP ohv speedway engine. 80mm bore x 90mm stroke. Output 39.5 bhp at 6,000rpm. Comp ratio 14.1. Weight 59lbs. Strongly built with good quality sheet steel, specially supported at points of attachment, finished in chromium.
Lubrication: Front Forks:
By double delivery Pilgrim oil pump with separate feed to rocker box. Capacity 1pt, chromium finish. Special Excelsior design Telescopic Forks, all steel construction and with high tubing, adjustable spring tension/trail.
Carburettor: Footrest:
Amal Twin Float racing Carb type 27 013 Adjustable on off side only.
Magneto: Exhaust:
B.T.H. KD1 C.6 special racing type with waterproof end cover Large Diameter pipe on RH side, rigidly mounted with 2 clips.
Frame: Transmission:
Excelsior design built with special steel tubing and proved by experience to be first class in service and control. Finished throughout in chromium plate. 1/2in x .305in Renold chain to S/speed C/shaft of Excelsior design. Heavy duty multiple plate clutch, Ferodo lined. Gear ratio of 8.95:1 variable through sprockets.
Cinder guards: Price:
Guard on front down tube. Rear guard fitted with side valance, both chromium plated. Complete machine with all accessories and ready to race:
£215 plus Purchase Tax £58

The Excelsior Mk1 (left)* housing here a JAP Long 5 engine.
This particular machine is actually frame number 36.

Later a Mk2 version was released, and a Mk4 version was also available around the same period that had an ultra lightweight frame and was intended for the more experienced rider who would be less likely to drop the machine.

* Missing (×)

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