Royal Enfield 1951 ISDT

Description

The Ex-Works, Jack Stocker, 1951 ISDT Gold Medal-Winning Royal Enfield 495cc Twin

• Registration No.: KAB 547
• Frame No.: T1870
• Engine No.: T2423 (also stamped W2515 on crankcase)

Key Highlights:

• The only known survivor of four built for the 1951 ISDT
• Featured in numerous publications
• Purchased in 1997

Launched in 1948, Royal Enfield’s twin followed traditional designs, though it featured unique aspects like separate barrels and cylinder heads, and an integrated oil tank within the crankcase, inherited from the Redditch firm’s singles. The new engine was placed in the Bullet frame, an advanced design with swinging-arm rear suspension. Royal Enfield’s post-war trials success was significantly due to this suspension, and the talents of works rider Johnny Brittain, supported by Jack Stocker, Stan Holmes, Don Evans, and Pat Brittain.

This historic Royal Enfield was part of the British team at the 1951 International Six Days Trial (ISDT) in Varese, Northern Italy, assigned to works rider Jack Stocker. His teammates included Hugh Viney (AJS), Jim Alves (Triumph), Bob Ray (Ariel), and Fred Rist (BSA). The British team finished the trial without losing any marks, winning the International Trophy for Great Britain. ‘KAB 547’ was one of four Royal Enfield 500 twins prepared for the ’51 ISDT, with three, including ‘KAB 547′, winning the Manufacturers’ Team Prize for the British firm. The fourth was ridden by Swedish Silver Vase team member Borje Nystrom, who also won a gold medal.

Capitalizing on this success, Stocker and his teammates were featured in Royal Enfield’s post-ISDT advertising, proudly sitting on their bikes. ‘KAB 547’ was also displayed on Royal Enfield’s stand at the 1951 Motor Cycle Show. In the 1952 ISDT in Bad Aussee, Austria, ‘KAB 547’ was ridden by Johnny Brittain as part of the British Vase B team but was sidelined on the fifth day due to engine failure. A handwritten note on file states that the factory 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 for the 1951 ISDT. The Royal Enfield factory register details are as follows:

• Frame and Engine Number: 1870
• Model: 500 Twin Works International Six Days Trial
• Date of Manufacture: 4.9.51 to works
• On Loan to: W Moore c/o Comerfords of Thames Ditton (W Moore was Royal Enfield’s Southeast England sales representative, living in Guildford)

In 1997, Bob Gardiner acquired ‘KAB 547’ from renowned sports photographer, writer, and off-road authority, Don Morley. Correspondence with Don is included in the substantial accompanying file, along with historical material on ‘KAB 547’ accumulated by Bob Gardiner. This file includes a list of all the publications featuring this historic machine. It should be noted that the V5C Registration Certificate still lists the original engine number, ‘1870’, although the engine is stamped T2432, which was originally dispatched to Pallister, Yare & Cobb of Middlesbrough on 18th February 1952.