
Ariel 4G Square Four Mark II
Key specifications
Overview
### Introducing the Ariel 4G Square Four Mark II The 1953 Ariel 4G Square Four Mark II, affectionately known as the 'Squariel', stands as a testament to mid-20th century British motorcycle engineering. Designed by the legendary Edward Turner, this motorcycle carved a unique niche in the all-rounder category, attracting riders who craved both innovation and performance. With its distinctive square four-cylinder engine and elegant design, the Mark II exemplifies the charm of classic motorcycles while providing a riding experience that remains relevant even today. Its striking aesthetics, combined with a robust build, make it an enduring favorite among collectors and vintage motorcycle enthusiasts. ### Engine Performance and Riding Characteristics At the heart of the Ariel 4G Square Four Mark II lies a 995cc square four-cylinder engine that churns out an impressive 45 horsepower at 5,500 RPM. This power translates into a top speed of 160 km/h (99.4 mph), making it a formidable contender on the open road. The unique configuration of the engine, with a compression ratio of 6.0:1, contributes to its smooth power delivery and distinctive sound. The 4-speed gearbox offers a seamless shift, allowing riders to effortlessly navigate through various terrains. Whether you’re cruising along country lanes or tackling city streets, the Mark II delivers a balanced ride, thanks to its oil-damped telescopic front forks and plunger-link rear suspension that absorb bumps and enhance stability. ### Key Features and Technology The Ariel 4G Square Four Mark II is not just about power; it’s also rich in innovative features that elevate the riding experience. Its tubular single-loop frame provides both strength and agility, while the dual drum brakes—203 mm at the front and 178 mm at the rear—offer reliable stopping power. The SU MC2 carburettor ensures efficient fuel delivery, contributing to its impressive performance. The Mark II also showcases a redesigned cylinder head with four separate exhaust pipes, enhancing the exhaust flow and adding to its distinctive charm. With a fuel capacity of 16 liters (4.23 gallons), riders can enjoy extended journeys without frequent refueling stops, a testament to its all-rounder capabilities. ###
Pros
Cons
- Distinctive Engine Design: The square four-cylinder configuration offers unique performance characteristics and a distinctive sound that appeals to enthusiasts.
- Comfortable Ride Quality: Exceptional suspension and weight distribution provide comfort on long rides and stability through corners.
- Classic Aesthetic Appeal: Timeless design elements and craftsmanship make it a sought-after model among vintage motorcycle collectors.
- Weight: At 193 kg (425.5 pounds), the Mark II may feel heavy to some riders, especially in low-speed maneuvers.
- Maintenance Complexity: The intricate design of the engine and its components may require specialized knowledge for maintenance and repairs.
- Limited Power Compared to Modern Standards: While impressive for its time, the 45 HP output may not satisfy riders looking for contemporary performance levels.
Technical details
Source specification data
- Make
- Ariel
- Model
- 4G Square Four Mark II
- Category
- Allround
- Light
- 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.
- Power
- 45.00 HP (32.8 kW)) @ 5500 RPM
- Gearbox
- 4-speed
- Top Speed
- 160.0 km/h (99.4 mph)
- Engine Type
- Double twin cylinder arranged as a square.
- Fuel System
- Carburettor. SU MC2 carburettor
- 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
- Lubrication System
- Dry sump with dual oil pump.
- Valves Per Cylinder
- 2
- Transmission Type Final Drive
- Chain
- Dry Weight
- 193.0 kg (425.5 pounds)
- Oil Capacity
- 3.40 litres (0.22 quarts)
- Fuel Capacity
- 16.00 litres (4.23 gallons)
- Overall Length
- 2,083 mm (82.0 inches)
- Power Weight Ratio
- 0.2332 HP/kg
- Seat
- Solo seat
- Wheels
- Wire spoked. Dunlop tyres.
- Rear Tyre
- 4.00-18
- Frame Type
- Tubular single loop
- 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
- 178 mm (7.0 inches)
- Front Brakes Diameter
- 203 mm (8.0 inches)