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Ariel 4G Square Four Mark II
1953Allround

Ariel 4G Square Four Mark II

Key specifications

Engine
995 cc
Power
45 HP
Weight
193 kg
Fuel type
petrol
Fuel capacity
4.2 L
Transmission
4-speed
Front brakes
Expanding brake (drum brake)
Rear brakes
Expanding brake (drum brake)

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)