1939 Ariel Square Four

1939 ARIEL SQUARE FOUR BACKGROUND
The original Square Four was conceived by legendary motorcycle designer, Edward Turner, who later created the game-changing Triumph parallel twin. His original design for the Square Four was an OHC (Overhead Cam) design with a displacement of 500cc when it debuted in 1931. However, constant overheating problems with the rear set of cylinders forced two redesigns, the latter being a total clean-sheet design. This new Square Four ditched the OHC for simpler OHV (Overhead Valves, ie: pushrods and rocker arms) and pushed the displacement all the way out to 1000cc. It launched in 1936 as the model 4G, and this 1939 Ariel Square Four is a fine example of the 4G. It would also be the last year of civilian production until after the end of World War II.

1939 Ariel Square Four SPECIFICATIONS

Engine type Displacement Bore & Stroke Compression ratio Fuel system Engine output Top speed Wheelbase Length Dry weight Primary drive Clutch Gearbox Final drive Frame type Front suspension Rear suspension Brake, front Brake, rear Tire, front Tire, rear Air-cooled OHV square 4-cyl w/2 crankshafts 997cc / 60.84 ci 55.0mm X 78.0mm / 2.60" X 3.10" 6.0:1 Single carburetor, SU MC2 35 hp @ 5500 rpm 87 mph / 146 km/h 56.0" / 1422mm 82.0" / 2983 425 lbs / 193.0 kg Chain Multi-plate, wet 4-speed constant mesh, right-foot shifting chain Steel tube single loop Girder Austey-type plunger 7-inch (178mm) SLS drum 7-inch (178mm) SLS drum 3.25" X 19" (3.25-19) 4.00" X 18" (4.00-18)

Check out these ARIEL BOOKS

ARIEL: THE COMPLETE STORY


ARIEL MOTORCYCLE WORKSHOP MANUAL 1933-1951, BY CLYMER


115 MPH ARIEL MOTORCYCLE CONVERSION


ARIEL SQUARE FOUR LIMITED EDITION EXTRA


ARIEL SQUARE FOUR SUPER PROFILE


BOOK OF THE ARIEL LEADER & ARROW 1958-1966


BOOK OF ARIEL 4-STROKE SINGLES 1939-1960


BOOK OF THE ARIEL - ALL PREWAR MODELS 1932-1939


ARIEL LEADER & GOLDEN ARROW - ROAD TEST LIMITED EDITION






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Last updated 9/5/17

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