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Sold 1959 Ariel Square Four Mk2

1959 Ariel Square Four Mk2




The history of Ariel dates back to 1869 when James Starley, an engineer with the Coventry Sewing Machine Co. of Birmingham, England, thought two-wheeled transportation held some promise.

In 1870 he and his partner William Hillman built a high-wheel bicycle and chose to name their company Ariel, a nod to the flying spirit from Shakespeare’s play The Tempest. Like many other British manufacturers that started out with bicycles, powered cycles soon followed. Ariel built a motorised three-wheeler in the late 1800s, and their first motorcycle in 1902.

In 1928, engineer Edward Turner was shopping a new motorcycle design to English manufacturers. BSA turned him down, but Ariel was interested. The engine was an unusual four-cylinder. V-twins and inline fours, set both lengthwise and across the frame, had been used previously but Turner’s new design had two vertical twins sharing a common crankcase. The cylinder barrels were cast as a unit in a monobloc design. Their two crankshafts were joined by a flywheel and rotated in opposite directions. By having the two pistons of one crank at top and bottom dead center and the pistons of the second shaft at half stroke, the design was ingeniously compact and the firing order made it practically vibration free.

The Ariel Square Four 4F made its debut at the 1930 Olympia Motorcycle Show featuring an overhead camshaft 500cc with a hand shift for the Burman gearbox, which was integral with the crankcase. Overhead camshafts and unit construction were well into the future for most firms, so Ariel was a real pioneer. Few knew then that the bike would become a legend of the British industry, both for its performance and dependability. The latter was underscored by the Square Four’s widespread used in the British law enforcement community.

Improvements were continuous during the Square Four’s 28-year production run. In 1932, the 4F was taken out to 600cc, although the 500 remained available. The next year, a 4F 600 fitted with a supercharger lapped the famous Brooklands speed bowl at 110 miles per hour. 4F production continued almost to the war, but some late 4Fs were fitted with 600cc overhead-valve engines.

The 4G was introduced in 1936 with a new 996cc overhead-valve engine. To accommodate the larger displacement, a new crankshaft was set in a much stronger crankcase. These years saw the British economy recovering in the run up to World War II, and Square Fours were seen on the road more often, where they were known as the “Monarch of the Multis”, referring to their multi-cylinder engines in a sea of British singles and twins. By the immediate post-World War II period, the 4G had a plunger rear end and telescopic front forks. Further refinement was added in the form of aluminum cylinder barrels when the Mark I began production in 1949.


  • The Ariel Square Four designed decades before, was keyed to another age, one where acceleration and all-out top speed weren’t as important as smoothness and reliability.
  • Air Cooled OHV Twin-crankshaft 4 cylinder with 1-SU side draft w/variable choke / 4 speed constant mesh / telescopic fork / hydraulic damping.
  • Two counter-rotating crankshafts not only gave it its name, but also provided a level of smoothness that was mostly unavailable in that era.
  • A very straight example in good condition.
  • This bike is in pretty good order. It is no trailer queen, starts on the first kick and can be ridden without drama.
  • This Square Four will engender a pride of ownership experience exceeded by few other marques.
  • Bike registration is on hold.
  • Complete with Books, Original handbook, VCC Historic Vehicle Data and lots of history.

This Bike is the final iteration of the Ariel Square Four, a Mark II 1000, from the final year of production.

The Mark II was introduced in 1953 and is the most desirable model of this iconic motorcycle. The monobloc cylinder barrel was replaced by individual units, resulting in four separate exhaust pipes, eliminating the overhead-camshaft engine’s weakness of overheating the rear cylinders. A redesigned head upped the power and the Square Four had no problem reaching “the ton” – 100 miles per hour.

Unfortunately, in 1959 the Square Four went out of production, a victim of the modern trend towards small, high-revving modern power units. The demand had tailed off a bit, and with reduced output, the price would have had to be hoisted excessively high. At the time it was approaching £350, out of reach of all but a few of the potential buyers.

Today, these Bikes are highly collectible.

Buy this bike, use it and admire it - they are becoming hard to find and are worth investing in.





This vehicle has been sold

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DISCLAIMER (Please Read)


Waimak Classic Cars accepts that the vehicle being sold must be of “acceptable quality” in terms of section 7 of the Consumer Guarantees Act 1993 (the Act) having regard to “the nature of the goods”.

Waimak Classic Cars is not aware of any specific defects with the vehicle, however (a) such a vehicle being a classic vehicle may have mechanical breakdowns, electrical failures at inconvenient times and maintenance costs being part of and parcel of ownership of a classic car; (b) reliability is a combination of the particular nature of the classic vehicle, how it is being driven, how it has been maintained, and to a certain extent luck.

The Purchaser acknowledges that the vehicle is being sold as a classic car; that in terms of the Act and the nature of the goods, the vehicle, is an old car that may have faults, unlike a modern motor vehicle.

The Purchaser is encouraged to personally fully inspect the vehicle and/or to have the vehicle inspected, fully assessed and maintained by an experienced classic car mechanic.

The Purchaser acknowledges that they have read and fully understand this notification and the nature of a car which is many years old.

For more information about this vehicle, please contact us Monday to Friday between 9:00am and 6:00pm (New Zealand Standard Time) on +64 (0) 3 310-6485 / +64 (0) 274 990-020. Alternatively, you may email us at info@waimakclassiccars.co.nz anytime.

PLEASE NOTE: Waimak Classic Cars is Not a car yard dealer type of operation. As a result, we do not operate through fixed opening hours and viewing is By Appointment Only.