
Ariel 4G Square Four Mark II
Key specifications
Overview
Introducing the 1959 Ariel 4G Square Four Mark II, a remarkable fusion of engineering and artistry that stands as a testament to the golden age of British motorcycling. Often affectionately dubbed the "Squariel," this motorcycle captures the imagination of enthusiasts with its unique square four-cylinder engine layout and classic aesthetics. Positioned as an allrounder, the 4G Square Four was designed for riders seeking versatility, whether cruising the open roads or tackling the rigors of daily commutes. With its robust build and timeless design, this model remains a cherished piece of motorcycling history, appealing to collectors and vintage aficionados alike. At the heart of the 1959 Ariel 4G Square Four Mark II lies a 995cc square four-cylinder engine that produces a respectable 45 horsepower at 5500 RPM, propelling the bike to a top speed of 160 km/h (99.4 mph). The engine’s unique configuration not only contributes to a smooth and balanced ride but also delivers impressive torque, making it an exhilarating choice for both novice and experienced riders. With a compression ratio of 6.0:1, the engine operates efficiently, achieving a commendable fuel consumption rate of 3.04 litres per 100 km, or an impressive 77.38 miles per gallon. Riders will appreciate how the 4-speed gearbox and dry 3-plate clutch work in harmony, providing a seamless transition through gears for a dynamic riding experience. The Ariel 4G Square Four Mark II is packed with innovative features that enhance its performance and comfort. A full cradle frame offers superior stability, while the oil-damped telescopic fork in the front and plunger-link spring suspension at the rear ensure a smooth, controlled ride over varying terrains. Stopping power is provided by reliable expanding drum brakes, with a 178 mm front and a more robust 203 mm rear brake diameter. The model boasts a stylish design, available in striking color options like Claret, Red/Black, and Black, making it as much a visual delight as a mechanical marvel. Designed by the legendary Edward Turner, the Mark II also features separate barrels and a redesigned cylinder head with four distinct exhaust pipes, showcasing a meticulous attention to detail that enthusiasts will admire. For those seeking the extra thrill of sidecar riding, this model offers that option as well. **
Pros
- Unique Engine Configuration: The square four-cylinder design provides smooth power delivery and unique aesthetics.
- Fuel Efficiency: With an impressive fuel consumption of 3.04 litres/100 km, it offers great mileage for an older motorcycle.
- Stylish Design: Classic looks combined with multiple color options make it a standout choice for vintage motorcycle lovers.
Cons
- Weight: At 197.3 kg (435.0 pounds), it may feel heavy for some riders, especially during low-speed maneuvers.
- Drum Brakes: While adequate for their time, the drum brakes may not offer the stopping power expected by modern riders.
- Kick Start Only: The absence of an electric starter can be inconvenient for some, particularly in urban settings or during chilly mornings.
Technical details
Source specification data
- Make
- Ariel
- Model
- 4G Square Four Mark II
- Category
- Allround
- Light
- 7.5 inch, 30 Watt headlamp.
- Starter
- Kick
- Comments
- Also
- called ´
- Squariel
- ´.
- Designed
- by
- Edward Turner
- .
- I
- has separate barrels, a re-designed cylinder head with four separate exhaust pipes from two cast-aluminium manifolds and a rocker-box combined with the inlet manifold.
- Sidecar
- option.
- Electrical
- 6 Volt
- Color Options
- Claret, Red/black, Black
- Power
- 45.00 HP (32.8 kW)) @ 5500 RPM
- Clutch
- Dry, 3-plate
- Gearbox
- 4-speed
- Top Speed
- 160.0 km/h (99.4 mph)
- Engine Type
- Double twin cylinder arranged as a square.
- Fuel System
- Carburettor
- .
- C2
- carburettor with air cleaner
- Bore X Stroke
- 65.0 x 78.0 mm (2.6 x 3.1 inches)
- Compression
- 6.0:1
- Displacement
- 995.00 ccm (60.71 cubic inches)
- Cooling System
- Air
- Engine Details
- Square four cylinder
- Fuel Consumption
- 3.04 litres/100 km (32.9 km/l or 77.38 mpg)
- Greenhouse Gases
- O2
- g/km. (
- O2
- -
- Carbon
- dioxide emission)
- Lubrication System
- Dry sump with dual oil pump.
- Valves Per Cylinder
- 2
- Transmission Type Final Drive
- Chain
- Oil Capacity
- 3.40 litres (0.22 quarts)
- Fuel Capacity
- 18.93 litres (5.00 gallons)
- Overall Width
- 686 mm (27.0 inches)
- Overall Length
- 2,184 mm (86.0 inches)
- Ground Clearance
- 140 mm (5.5 inches)
- Weight Incl Oil Gas Etc
- 197.3 kg (435.0 pounds)
- Wheels
- Wire spoked. Dunlop tyres.
- Rear Tyre
- 4.00-18
- Frame Type
- Full cradle
- Front Tyre
- 3.25-19
- Rear Brakes
- Expanding brake (drum brake)
- Front Brakes
- Expanding brake (drum brake)
- Rear Suspension
- Plunger-link spring
- Front Suspension
- Oil damped telescopic fork
- Rear Brakes Diameter
- 203 mm (8.0 inches)
- Front Brakes Diameter
- 178 mm (7.0 inches)