Bonhams | 16-Oct-2016 | The Autumn Stafford Sale Important Collectors Motorcycles | Venue : Stafford, Staffordshire County Showground
Category : Classic Motorcycles
Lot No. : 164
Year : 1971
Engine Size : -
Registration No. : WPY 105K
Chassis No. : # 2935831
Engine No. : # 2935831
No longer available - Sold or withdrawn from sale


• Based on an R65 roadster
• Professionally built in 2015
• Featured in The Classic Motor Cycle (May 2016 edition)
BMW motorcycles had been raced since the company's arrival on the two-wheeled scene in the early 1920s, but it was not until the late 1930s that they began to make a significant impact outside Germany. The development of supercharging technology in the late 1920s had enabled Ernst Henne to set a string of motorcycle speed records for BMW, so forced induction was a logical choice when the company decided to go road racing. When the new 500cc Rennsport (RS) appeared in 1935 it was powered by an advanced double-overhead-camshaft engine complete with Zoller 'blower' mounted on the front of the crankcase.
Targeting the Isle of Man TT, BMW made its first official appearance at the world's most prestigious road race in 1937, works rider Jock West finishing 6th in the Senior race. West followed up this promising performance by winning that year's Ulster Grand Prix but BMW would not achieve its ultimate goal until 1939, when Georg Meier brought the coveted Senior TT trophy back to Munich.
With supercharging banned after the war, the Rennsport engine was reconfigured for normal aspiration and found its true métier as a sidecar power unit, winning 20 Manufacturers' World Championships between 1954 and 1973. Although redesigned with a Norton Featherbed-style frame, the solo Rennsport was outclassed at Grand Prix level, Walter Zeller's win at Schotten in 1953 - an event boycotted by the major title contenders - being the sole World Championship victory. Technological innovations pioneered on the Rennsport sidecar engine, including fuel injection, duly found their way onto Zeller's works bike, which by 1956 had reached the peak of its development. At that year's Isle of Man TT Zeller finished 4th in the Senior event before going on to claim 2nd place at both the Dutch and Belgian Grands Prix, finishing the season 6th in the World Championship.
Intended for supply to selected private owners, the Rennsport, although subsidised by the factory, was an expensive purchase and relatively few were sold. With most either in private hands or in museums, the only option for many enthusiasts is the creation of a replica, such as the machine offered here, which was built in 2015 by Jason Blackiston of Anson Classic Restoration using a 1971 BMW R65 road bike as the basis.
The R65 was comprehensively overhauled during the transformation, which included removing the starter motor and altering the crankcases to make the engine look more like a Rennsport. Surplus lugs were removed from the frame, and a set of new Earles-type leading-link forks acquired from Germany. The original fuel tank was expertly reshaped and a original-style racing seat fabricated, all of this work being carried out in-house. The R65's instruments have been retained, neatly hidden behind the number-plate/fly-screen, and the machine is road legal for daytime use. New Mikuni carburettors are fitted in place of the original Bing units (included in the sale).
After completion, Jason's Rennsport re-creation was featured in The Classic MotorCycle (May 2016 edition, copy available) and the machine also comes with a detailed list of the works carried out and components fitted/modified. Offered with a V5C document, and freshly MoT'd, this superb re-creation represents a wonderful opportunity to acquire a convincing Rennsport look-alike at a mere fraction of the cost of an original.