Royal Enfield 1951 ISDT Description.
The ex-works; Jack Stocker; 1951 ISDT Gold Medal-winning
1951 Royal Enfield 495cc Twin
Registration no. KAB 547
Frame no. T1870
Engine no. T2423 (also stamped W2515 to crankcase)
• The only known survivor of four built for the 1951 ISDT
• Pictured in numerous publications
• Purchased in 1997
Launched in 1948, Royal Enfield's twin followed orthodox lines, though the use of separate barrels and cylinder heads, and the incorporation of the oil tank within the crankcase - a feature inherited from the Redditch firm's singles - was unusual. The new engine was installed in what was basically the Bullet frame, the latter an advanced design featuring swinging-arm rear suspension. Royal Enfield's success in post-war trials owed much to its being first in the field with swinging-arm suspension, but arguably more to the talents of works rider Johnny Brittain, ably aided by the likes of Jack Stocker, Stan Holmes, Don Evans and younger brother Pat.
This historic Royal Enfield was used by the British team at the 1951 International Six Days Trial (ISDT), held that year at Varese, Northern Italy. It was assigned to works rider Jack Stocker, whose team-mates were Hugh Viney (AJS), Jim Alves (Triumph), Bob Ray (Ariel) and Fred Rist (BSA). The British team completed the trial without losing any marks, winning the International Trophy for Great Britain. 'KAB 547' was one of four Royal Enfield 500 twins prepared by the factory for the '51 ISDT, three of which (including 'KAB 547') won the Manufacturers' Team Prize for the British firm. The fourth was ridden by the Swedish Silver Vase team's Borje Nystrom, who also won a gold medal. Capitalising on this success, Stocker and his two team-mates were featured in Royal Enfield's post-ISDT advertising, sitting proudly on their mounts. 'KAB 547' was also displayed on Royal Enfield's stand at the 1951 Motor Cycle Show.
In the following year's ISDT, held at Bad Aussee in Austria, 'KAB 547' was ridden by Johnny Brittain as part of the British Vase B team. Unfortunately, he was sidelined on the fifth day with engine failure. A hand-written note on file states that the factory then rebuilt the engine with new parts while retaining the original cylinder heads. 'KAB 547' is the only known survivor of the four Royal Enfield twins built by the factory for the 1951 ISDT. The Royal Enfield factory register records the following details:
Frame and engine number 1870
Model 500 Twin
Works International Six Days Trial
Date of manufacture 4.9.51 to works
Then on loan to W Moore c/o Comerfords of Thames Ditton (W Moore was Royal Enfield's Southeast England sales representative, living in Guildford)
Many years later, in 1997, Bob Gardiner was able to buy 'KAB 547' from the famous sports photographer, writer, and recognised off-road authority, Don Morley. Correspondence with Don may be found within the accompanying substantial file together with historical material relating to 'KAB 547' accumulated by Bob Gardiner, which includes a list of all the many publications in which this historic machine has appeared (perusal recommended). It should be noted that the V5C Registration Certificate still lists the original engine number, '1870'.
The engine is stamped T2432, originally despatched to Pallister, Yare & Cobb of Middlesbrough on 18th Feb 1952.
