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1951 Vincent Comet

1951 VINCENT COMET RUNNING GEAR

The Vincent Comet had frame similar in layout to the V-twin Vincent Black Shadow which included Vincent’s proprietary cantilever rear suspension and Vincent’s Girdraulic forks up front. And, like the big V-twins, the engine was a stressed member of the frame, eliminating the need for front downtubes and an engine cradle. This saved weight and mass, and helped ‘the little Vincent’ punch well above its weight class.

VINCENT COMET ENGINE DESIGN
The Comet engine was an air-cooled 499cc OHV single with its camshaft set high in the crankcases. Both the cylinder block and cylinder head were made of aluminum alloy with a cast iron cylinder liner. The compression ratio was 7.3:1. These engines included a very unique valve arrangement with two valve guides on each valve with the forked rocker arms acting on that portion of the valves that laid between the two guides. This gave the valves more lateral support and a much straighter path. The Comet single served as the basis for the V-twin engine in the Vincent Black Shadow, they just doubled everything. The gearbox was a Burman BAP 4-speed, all set in a unit-construction case.

1951 Vincent Comet SPECIFICATIONS

Series

Engine type

Displacement

Bore & Stroke

Compression

Carburetor

Ignition

Engine output

Charging

Primary drive

Clutch

Gearbox

Final drive

Chassis type

Suspension, front

Suspension, rear

Tire, front

Tire, rear

Wheelbase

Seat height

Weight

Top speed

C

Air-cooled OHV single

499 cc

84mm X 90mm

7.3:1

Amal 1-1/8″

6-volt Lucas magneto

28 bhp @ 5,800 rpm

50-watt Miller dynamo

Chain

Multi-plate, wet

Burman BAP 4-speed, right-foot shift

Chain

Oil-bearing, engine as stressed member

Vincent Girdraulic telescopic form

Cantilever

3.00″ X 20″

3.50″ X 19″

55.75″

31.0″

390 lbs dry; 415 lbs curb

90 mph