At the heart of the 1949 Ariel 4G Square Four 1000 allround motorcycle, Ariel pairs a 995 cc (60.7 cu in) air-cooled square four cylinder architecture with road-focused gearing. In factory specification, peak output is rated at 35 HP (25.5 kW) at 5,500 rpm, transferring power to the rear wheel through a 4-speed gearbox and chain final drive. With a specific output of 35.2 HP per liter, the engine character is prioritizing low-RPM tractability, mechanical longevity and relaxed throttle response over peak redline numbers.
On the scales, the 4G Square Four 1000 measures 211 kg (465 lbs) wet (curb), translating to a power-to-weight ratio of 0.17 HP/kg (6.03 kg per horsepower). Rider ergonomics and chassis geometry center around a 1,422 mm (56 in) wheelbase engineered for balanced agility and highway composure. The 23-liter (6.1 US gal) fuel tank supports practical everyday commuting and weekend road stints, while factory top speed is listed at 140 km/h (87 mph).
Within MotoLibrary's Ariel archive, this model family spans 14 indexed model years from 1936 to 1949, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.
Specific Output
35.2 HP/L
Power-to-Weight
0.17 HP/kg (6.03 kg/HP)
Engine
Displacement995.0 ccm (60.71 cubic inches)
Engine TypeSquare four cylinder
Engine DetailsDouble twin cylinder arranged as a square
Power35.0 HP (25.5 kW)) @ 5500 RPM
Compression6.0:1
Bore x Stroke65.0 x 78.0 mm (2.6 x 3.1 inches)
Valves/Cylinder2
Fuel SystemCarburettor. SU MC2 carburettor
Fuel ControlOverhead Valves (OHV)
CoolingAir
Transmission
Gearbox4-speed
Final DriveChain (final drive)
Performance
Top Speed140.0 km/h (87.0 mph)
ExhaustDual two-into-one
Chassis
Frame TypeTubular single loop
Front SuspensionOil damped telescopic
Rear SuspensionPlunger-link spring
Wheelbase1422 mm (56.0 inches)
Wheels & Brakes
Front Tyre3.25-19
Rear Tyre4.00-18
Front BrakesExpanding brake (drum brake)
Front Brake Ø203 mm (8.0 inches)
Rear BrakesExpanding brake (drum brake)
Rear Brake Ø178 mm (7.0 inches)
WheelsWire spoked.
Dimensions & Weight
Weight incl.211.0 kg (465.2 pounds)
Overall Length2083 mm (82.0 inches)
Fuel Capacity23.00 litres (6.08 US gallons)
Other
StarterKick
Color OptionsRed/silver
Notes
Also called ´Squariel´. Designed by Edward Turner. The Ariel Square Four Mark I replaced this model in 1949.
Use this page to compare this motorcycle by its real specifications, not only by model name. Focus on the details that affect fit, comfort, handling, range and ownership.
Power
Compare engine output with similar motorcycles if acceleration, highway use or two-up riding matters.
Fuel Capacity
Fuel capacity helps estimate touring range and how often you may need to stop.
Brakes
Brake setup is worth comparing if you ride in traffic, mountains or with a passenger.
Suspension
Suspension details can matter for comfort, road feel and long-distance riding.
Transmission
Transmission and final drive affect maintenance, smoothness and everyday usability.