The other day, we went around to a private collector and came across this old beauty. At the time, we had no idea of this bikes rarity. It runs and will hopefully be at this years SA Classic TT.
Some racing history.
“One of the rarest of all Vincents — an engineering masterpiece — but one that was simply the wrong machine at the wrong time to make a huge impact”
At the age of 16 John Surtees who became a world champion racer was an apprentice at the Vincent Factory. In 1951 John made his first headline as he gave Norton star Geoff Duke a proper challenge in an ACU race at the Thruxton Circuit. In 1952, Surtees set a new lap record at Brands Hatch.
In the early 1950s he was virtually unbeatable on the Vincent Grey Flash race bike.
The Grey Flash was only made between 1949 and 1952 by Vincent Motorcycles. With only 31 bikes produced. Talk about rare!
Phil Irving designed the Vincent Comet that provided the basis for the Series C 499cc Grey Flash Racer.
It was tuned and stripped down to 150 kg as a 500cc version of the 1000cc Vincent Black Lightning. The new ‘Flash’ was capable of 185 km/h with a power output of 35 bhp at 6,200 rpm.
In 1949 prototypes were raced and the last model was produced in 1952. Small numbers meant there was a lot of variation of the specs. Earlier models had chrome on the fuel tank and lower fork link close to the end of production in 1952 it was replaced with grey paint. Also came with the Burman BAR gearbox and they experimented with AJS 7R gearboxes.
Albion gearboxes were used for most of the motorcycles produced.
The Grey Flash was produced in Racing, Dual Purpose and Road models, as well as Show models and a number of ‘TT specials.
Debate about the number of the Vincent Grey Flash has gone on for years. Officially, only 31 were registered, several were known as rebuilds. Many Grey Flash bikes that did survive have been raced and modified to keep up with ever changing racing regulations. Some have been restored to the higher specifications for the TT machines, hence being a very rare motorcycle.
Some interesting info:
The Grey Flash grew out of the 500cc Comet, designed in 1935 by Australia’s Phil Irving. Irving joined Vincent in 1930 after riding as passenger to Jack Gill in a Vincent-HRD sidecar from Melbourne to London via North America.
When designing the Comet, Irving selected the bore of 84mm as the smallest cylinder he could get his hand in for cleaning. A 90mm stroke provided 499cc and these would be the dimensions of all Vincent singles and twins until 1955.
The most unusual feature of the Vincent engine was the valve train, which Vincent liked to refer to as “semi-overhead camshaft”. This wasn’t really correct, but the high camshaft allowed for shorter pushrods in splayed aluminium tunnels and reduced engine height.
Each valve moved through double guides, with the forked rocker acting on a collar in the middle of the valve stem. This reduced side thrust on the rockers and allowed for large hairpin valve springs to be externally mounted.
The engine bristled with special components, from higher-lift Mark II cams, polished conrods, triple valve springs, and opened-out polished ports.
With an 8:1 compression ratio and a 50mm straight-through racing exhaust, it produced 35hp (28kW) at 6200rpm. This one belongs to a private collector in JHB. With a bit of luck, it will make an appearance at the Kyalami leg of this years SA classic TT.
