When it comes to the most valuable British motorcycles, there is Vincent, Brough Superior, and the rest. So, the appearance of a historic Vincent at Bonhams Stafford bike sale in July is sure to attract considerable attention from the world’s top collectors.

This 1938 Series A Rapide is an early example of the original, 100mph-plus machine born after engineer Phil Irving absent- mindedly overlaid a tracing of his 500cc Vincent engine onto an identical drawing, leading to the realisation that putting the two together would result in a 1000cc v-twin.

A mere 77 Series A Rapides were made, and around 50 are thought to have survived. The Bonhams bike is particularly covetable for being the original factory demonstrator, and the actual machine tested by Motor Cycling magazine at Brooklands in April 1938, where it achieved 102mph and marked the Rapide as the world’s fastest production vehicle. Two further Rapide series followed, plus the Series D tourers, with higher-performance Black Shadow and Black Lightning variations evolving from the Series C, along with rarities such as the White Shadow.

This Series A was also the mount of Vincent’s directors and, surprisingly, could well have been the last machine to leave the Stevenage works when it closed its doors in December 1955. The ’bike was retained as ‘factory demonstrator’ for 17 years and was still on the premises when the business folded. It was only taken away after Motor Cycling conducted a ‘first and last’ road test along with the Series D Black Knight.

What became of DUR 142 immediately afterwards is unknown, and the ’bike remained hidden for over 50 years before it was consigned to Bonhams after a long-running game of cat-and-mouse, according to Mark Garside, the firm’s motoring department rep. for the north of England and Scotland.

“It is particularly gratifying to bring a historic machine such as DUR 142 back into public notice after over half a century of hibernation,” he says. “Machines such as this very rarely come to market, and it has taken years of patience to successfully consign this particular motorcycle.”

Despite the bike’s need for restoration, its significance could make the pre-sale estimate of £190,000-£220,000 conservative. In February 2018, the Black Lightning Jack Ehret used to set a new Australian land speed record of 141.509mph in 1953 reached $929,000, the most ever paid for a motorcycle at auction.

DUR 142 is unlikely to better that but, assuming the world has returned to some form of normality by the time of Bonhams August sale, the bidding is likely to be intense…

1938 Vincent-HRD Rapide Series A
On sale at Bonhams, Stafford, August 15-16.
Estimate £190,000 – 220,000
bonhams.com