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Manufacturer: Norton
Model: 7 / replica Brooklands Special
Year: 1920
Displacement: 490 cc
Cylinder: 1
Engine type: 4-stroke / sv
Bore / Stroke: 79 x 100 mm
Power: c.15hp @ 4500 rpm
Weight: 92 kg
Top Speed: at least 120 km/h
Info: ex Dr. George Cohen collection
Frame number: 3208
Engine number: 4104
Having hitherto relied on proprietary engines, Norton introduced its own in 1907. The long-stroke sidevalve single displaced 633cc and the new model it powered became known as the 'Big 4'. Smaller capacity versions followed and in 1911 the '500' adopted the classic 79x100mm bore and stroke dimensions that would characterise the half-litre (actually 490cc) Norton for the next 50 years. Norton's new sidevalve was among the fastest in its class, being the first machine under 500cc to be officially timed at over 70mph, which was some going for 1911. The following year Norton-mounted Jack Emerson easily won the 150-mile Brooklands TT against a field of more experienced competitors (setting three long-distance records in the process) having ridden his machine down from Hull! Small wonder that the slogan 'Unapproachable' began to be applied to the Norton singles at around this time. Tuner/rider Dan O'Donovan's work at the Weybridge track resulted in the introduction of tuned 'Brooklands' models in 1913, and these highly developed sports versions continued into the 1920s.
When the first productions models were produced in 1912 and known as the BS and BSR (Brooklands Special and Brooklands Special Road according to specification), they were sold with guarantees to lap Brooklands track at Weybridge at 70mpg and 65mph respectively (one lap). Mr. Dan O'Donovan and his team were testing about 30 engines of BRS and BS per month. In 1920 both racing models were available the “Brooklands Special” and “Brookland Special Road” both without silencer. The BS has no tool box in the rear and no front mudguard. The Brooklands models are built to be fast and break records. The customer could order the bike with gearbox or for extra money direct belt drive with Philipson Adjustable Pulley. This pulley are able to change the gears ratio from 5.50 to 3.75 to 1. The most racing driver ordered this bike with the Philipson pulley to reduce weight. Norton catalogued the BS for 68 pounds and for extra money the Philipson pulley for 3 pounds.
According to its manufacturer advert: A speed mount with highly refines engine, each one tuned and tested at Brooklands and timed, the timekeeper issuing a signed certificate with each engine to the effect, that at least speed of 70mph for the lap, or 75mph for the kilo, has been exceeded by the “Brooklands Special” engines and the 65mph for the lap or 70 for the kilo for the “Brooklands Road Special”.
Great article about this model: motorcycleandmo... - In the middle of this article there is a pic. of this bike we have offered here.
Article about Dr. George Cohen alias “Norton George” or “Flat Tank George”: thevintagent.c... Dr. George Cohen wrote the Bible of Norton motorcycles: Book “Flat Tank Norton” ISBN: 0955374308.
This bike is featured in this book on page 106 and 215.
This bike is additional featured in the magazine "British Classics" Issue 1/20019
Due to the rarity of this model the builder has decided to create this fast Brooklands Special to high standard. It’s an outstanding racing bike from the Dr. George Cohen collection. It runs powerful and very well. It’s a light and fast bike!!
ka0003