1954 Ariel Square Four 'Special', fully rebuilt by expert, runs perfectly!

Expertly restored by a marque expert!1954 Ariel Square Four ’Special’ Engine Number: PL131 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. 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. Soon after WWII an American Air Force pilot began flying back and forth from his base in California to bases in southern England. While on one of these trips he discovered the Ariel Square Four and was smitten. He purchased a bike to run around the country lanes while in England and then with a little room to “spare” on the return flight he snuck the bike on and brought it back Stateside. Enjoying the bike in the Southern California backroads was the perfect setting and soon friends and colleagues became interested in the quirky British ‘four’ in a time the American competition offered nothing but archaic pre-war designs. And so a little side business developed with frequent trips to the UK and return flights with undeclared Ariel motorcycles and an abundance of parts filling the spare room of the planes. This continued on for many years and the gentleman in question – let’s call him Chuck – made use of his engineering background and restored and maintained many Ariels. Practically starting the Ariel Owners Club he remains an active member to this day. Retiring in 1990 the hobby continued on and to date he has rebuilt 107 engines for himself and clients/friends and restored many bikes from the ground up. To say he is an expert of the marque is just scratching the surface. His knowledge is encyclopedic and having restored so many engines understands every pitfall of the unique design and precisely how to prevent engine failure. Tricks to rod bolts (a well-known weak point of the engine) rocker arms crank bushings valve guides and springs ensure engines with great power superb reliability and great longevity. The bike on offer is one of Chuck’s personal favourites. It’s a bit if a bitsa made up of great parts from various era of Square 4 from 1949 to 1958. At the core is a 1954 bike with matching numbers on engine frame and gearbox. At the front is a 1954 front end with a ’49 fender while out back is a ’56 fender over a Harley rear wheel! The tank is from a 1950 single cylinder Ariel . At the heart of the machine is one of Chuck’s fully rebuilt motors. Rebuilt from the crank up and featuring all of his tricks and nuances the engine is in fine tune with strong power having covered a mere 2500 miles since. The bike is built for the long distance haul with 70mph+ cruising speeds from the longer gearing (21 teeth at the gearbox instead of 19) and with the internal tweaks and oil cooler remains at proper running temperature whilst doing so. Brakes and all suspension parts were restored and a new correct wiring harness was installed. Meticulously maintained the bike is offered in excellent condition throughout in the very unusual British Racing Green livery. It has been featured in numerous magazine articles including the UK’s Classic Bike. This is a great opportunity to acquire a fantastic riding Ariel Square Four built by a true aficionado accomplished engineer and one of the world’s leading marque experts. It is ready to ride anywhere and enjoyed in the process.

Also published at eBay.com