The original Copperknob was built by Ben Bickell and his brother Joe at their Highgate, London garage, in 1929, from the bones of a salvaged Chater-Lea A.A. sidecar outfit! The former 'tug' frame soon housed variously J.A.P. single and twin-cylinder engines, and a rare Chater-Lea 350cc 'Face Cam' OHC engine. The lovely all-copper plate finish was purely decorative, although plating does show up cracks in tubing and metal plate.
The final configuration seen here uses a new-for-'31 J.A.P. 'Dog Ear' 500cc OHV 'track' engine, which the factory was keen to introduce to the racing fraternity, so sponsored a race at Brooklands with machines using this engine exclusively (and you thought the one-make race series was invented by BMW or Ferrari?). The April 1931 race was won convincingly by 'Copperknob' at 93.97mph. More success followed; in 1932 the gleaming machine laid down a 112.17mph lap during a Senior Handicap race at Brooklands, and averaged 99.61mph over 100 miles during a 'Hutchinson Hundred' race, in a driving rain. The gleaming copper plating on all steel body parts, combined with the history of track success, fixed Copperknob in enthusiast's memories. The motorcycle survived passage through many owner's sheds until the early 1960s,when it was completely restored, featured in several books, and displayed at Vintage Motorcycle events.
Here, Urban tells his own tale of recreating a machine which stirred his imagination:
"I was idly flicking through a copy of Classic Bike 2000 or 2001 (I think it was), and nothing much caught my attention until I reached page 30, and suddenly there was the bike which utterly transfixed me!
The frame and forks are from a 1929 Husqvarna TV50, the front hub is from a 1940s Speedway bike. The engine is 1947 JAP sprint 500cc OHV with 1930s Amal track carb, BTH-TT magneto, three-plate one-spring clutch and Sturmey-Archer 3-speed gearbox.
I built the fuel tank, oil tank, foot controls, and the exhaust; a "Brooklands silencer". The engine runs on alcohol as in the old days.