For a company steeped in the tradition of sporty four stroke singles and twins, plus the long serving Square Four, Ariel took a leap into the unknown with its first two-stroke – discounting the 1916 design that failed to reach production due to the concentration on the war effort.
The Ariel Leader of 1958 demonstrated that there was still original thinking to be observed within the struggling British motorcycle industry, although it had taken three years to turn the initial ideas into metal. Legendary designer Val Page was behind the drawing board, and with credits like the BSA Gold Star, BSA A7 and even as far back as the OHV V-twin J.A.P. engine, Page had the runs on the board, even if he were past the usual retirement age. But the Leader was a quantum leap in virtually every respect; designed to appeal to a new generation of motorcyclists, rather than pandering to the traditional, and staid, market. Page’s design abandoned the usual tubular steel frame by utilizing a structure made up of pressed 20-gauge steel sections, welded together, with the engine suspended at three points from the underside of the front section, the rear mounting serving as the swinging arm pivot. The rear mounting bracket did double duty as an air-silencing chamber, with a stub for the replaceable element air filter, with a rubber hose leading to the Amal Monobloc carburettor. The very rigid box-section frame had a hollow middle section, into which a fuel tank made from two pressings was dropped. In the space where the fuel tank usually sat was a dummy tank that was actually a luggage compartment, accessed via a lockable lid. The engine unit was concealed behind more pressed steel panels which could be easily removed for maintenance via five screws. An entirely new design, the engine was conceived by Page and his assistant designer, Bernard Knight, who had had a considerable influence in the BSA Bantam. To ensure the unit was as low and compact as possible, the twin cylinders were inclined steeply forward at 45º, and to keep the width down, the cylinder centres were as close together as possible. Bore and stroke were identical at 54mm, with 180º firing intervals. Cylinder heads were pressure diecast in light alloy with part-spherical combustion chambers. The crankcase, housing both the engine and gearbox with an air space between, plus the inner half of the primary chain case were cast in one and not split, with the main bearings housed in detachable end covers. This was an incredibly complex affair in pressure die-casting, the die having no fewer than 68 components. Thus it was possible to dismantle the engine completely without removing it from the frame, but required the crankshaft to be made in two halves, with mating-taper and end-key coupling held together
by a socket-headed draw bolt, with no middle journal. As well as the inner steel flywheels, the Leader used an external cast-iron flywheel housed in the primary chain case, which also contained a leaf-spring tensioner for the primary chain. Internals for the four-speed gearbox had their origins in the proven Burman CP box, with the gears narrowed. A neutral-indicator switch, fitted into the rear of the gearbox casing, was a novel fitment for the era. The complete engine/gearbox unit tipped the scales at just 84lb (38.2kg). The multitude of pressed panels (eight in total, not including the mudguards) required a considerable investment, so great that it was decided to ease out the remaining Ariel four stroke models. Mudguards, headlight cowling, engine covers, leg shields (into two sections), tail unit (which hinges upward for rear wheel removal), rear chain case and even the front forks were all pressings. The forks themselves were of trailing link design with the hydraulic spring/ dampers concealed inside each leg. The die-cast trailing links, made from heat-treated light alloy, were arranged so that the wheelbase did not alter with suspension movement.
To ease the life of the hidden rear chain, an oiler was built into the rear of the primary chain case, with drops of lubricant reaching the chain from a wick feeder. A bugbear of two-stroke, gunking up of the exhaust silencers, was alleviated by the fact that the entire baffle system of the Ariel-designed units could be removed for cleaning. Lifting the Leader onto its centre stand is accomplished using a telescoping tubular push button type handle that springs in/out, just under the seat. Standard fitment included a steering lock and a lockable dual seat, both of which were accessed via the dummy tank compartment, and a trimmer for the headlamp beam, operated by a lever on the dashboard.
Under the seat sat the filler cap for the fuel tank, battery and tool kit. Witnessing the added profits derived from automobile and scooter manufacturers making and selling options to adorn their products, Ariel joined in. Ariel offered a long list of options to the buying public, however few could actually afford all that were offered, if indeed they wanted them. The Leader’s options included rear view mirrors, turn signals (termed “trafficators”- a first on a production British motorcycle), side stand, windscreen extension, eight day clock (now so rare, some buy a complete Leader just for the elusive clock), lockable panniers with vinyl inserts (removable for shoppingpredating both the advent and demise of the plastic shopping bag), neutral indicator light, waterproof seat cover, luggage rack with elastic ties, parking lamp, front stand, 80 mph speedometer with tripometer, rear mudguard, chrome plated rear bumper and an inspection lamp (aka trouble lamp). A Perspex screen was standard fitment as was a dashboard for the instruments.
In keeping with the Leader’s avant garde styling, the décor broke new ground too. Two colour options were listed; Cherokee Red or Oriental Blue, both with contrasting Light Admiralty Grey panels. To British eyes, the Leader represented a complete departure from convention, which sat better with some than with others. Thick amongst the latter were the Americans, who had no liking for pressed steel frames of any type. The failure of the Leader in the vital US market was a major factor in its comparatively short existence. It was pricey too, and a bit on the porky side with just 17.5hp to push it along. Although the new machine received rave reviews from journalists and road testers (and was awarded 1959 Motorcycle of the Year by Motorcycle News publication), overall sales were sluggish. Ariel’s answer was to produce a second version stripped of the body panels, leg shields and dashboard which was named the Arrow, launched in 1960. It was lighter, faster, and considerably cheaper. One year later a revised version appeared with a redesigned cylinder head that gave more power, at the expense of smoothness.
It was however, a case of too little, too late, and in 1963 the old Ariel plant in Selly Oak, Birmingham was closed and production transferred to the main BSA facility in Small Heath. In 1964 a revised model, the Arrow 200 appeared, officially to sit under the 200cc level favoured by insurance companies, but actually to use up the piles of surplus parts that still lay in the old Ariel factory. It was merely a stay of execution, and by 1965 both the Leader and the Arrow were no more, and the Ariel name effectively ended, although BSA used the brand on two unloved and unsuccessful attempts, the Pixie and the Ariel 3, both destined to short and ignominious lives.
A double Leader
Back in 1962, while many other British motorcycle companies were shrinking their ranges, Ariel had other ideas. The 2-stroke twin Leader had been struggling to find buyers and was now essentially competing with cheap small cars as much as other motorcycles. In a rather bold move, parent
“To British eyes, the Leader represented a complete departure from convention, which sat better with some than with others.”
company BSA diverted precious resources into the creation of a prototype four-cylinder 692cc Leader; not a two stroke but an overhead valve four stroke with the crankshaft running fore and aft and the engine laid flat; a design which preceded the BMW K series by more than 20 years. The engine actually had its origins as a design destined for an Army contract – another Val Page creation of 400cc.
The ‘Leader 4’ had the fan-assisted air-cooled horizontal cylinders out the left side of the motorcycle, with the wet sump on the right, a syncro-mesh gearbox and a single plate clutch taken from the Morris Minor car. The engine breathed through a single Zenith carburettor, with coil ignition, electric starting and shaft final drive. The frame and bodywork were very similar to the 250cc Leader with careful attention to comfort and weather protection, with twin headlights being the main distinguishing feature. However the prototype produced only around 25 horsepower and was no lightweight, so performance was hardly shattering. The BSA board was unconvinced of the Leader 4’s potential and refused to fund the model into production, but the real reason for the decision was a massive cut back in military spending and the subsequent cancellation of the vital contract for which the engine had been originally designed. Today the prototype ‘Leader 4’ exists in the National Motorcycle Museum in the British Midlands.
An owner’s opinion
Bryan Fowler is very keen on his Ariel Leader, which he says is “the first bike to be marketed like a car. You start with the basic bike, then option it up with
indicators, rear bumper, extra lights etc. The engine and gearbox can be stripped in frame which was a real breakthrough in ease of maintenance.”
A Leader restoration is not for the faint hearted, says Bryan. “Unlike its contemporaries, Ariel opted to make the Leaders’ fasteners and threads as S.A.E. – perhaps in anticipation of catering to the U.S.A. market (an anticipation that did not eventuate). The exception to this is the gearbox, in which some threads are metric, thereby revealing the Leader’s Adler influence. There are few “specialty” tools required to work on the Leader and they are well worth having for any owner; for example a flywheel puller, contact point/oil seal centre. “Although production (1958-1965) was limited to about 22,000 units, most spares are available and some of the options are being replicated. Draganfly (U.K.) has been an invaluable source of both parts and advice. On a personal level, having dealt with Draganfly for some years, it is not unheard of for me to receive parts ordered from them, with a handwritten note asking me to please update my credit card details so that they can then charge me for the parts they’ve already shipped to me without charging me! They kindly explained that “they’re used to dealing with “grey beards” who often forget such details”. “As noted the Leader is a combination of a scooter and a motorcycle. While most readers may have worked on one or the other, in my experience, few have worked on a singular combination of both, and as such restoring a Leader may not suit those who are experienced or wedded to one camp or the other. Having worked on both motorcycles and scooters, in as much as I may have had the practical experience at hand, the process was more complicated. For example, the Leader comprises approximately 65-70 separate parts to be prepped and then painted in one of two colours, depending on the specific part, as the final result is a two-tone painted motorcycle. Once painted, assembly requires careful attention to detail as each part assures the correct alignment and the basis for the next part. However any maladjustment of the first part is often not discernible until the following part is added, thereby necessitating a readjustment (or removal) of the first (and second) part to correct each. I confess, while restoring the Leader, my locking needle nose pliers were always close at hand due to the all too often difficulty accessing fasteners, and often, I stood back, wondering how in the hell Ariel ever made any money from these machines, given their complex assembly/structures. “There is for me, an inherent and on-going juxtaposition in riding my Leader. In as much as the Leader is, in my mind, undoubtedly a futuristic, innovative and indeed, revolutionary and radical motorcycle light years ahead of its time/contemporaries (it embodies much of what my 2011 BMW R1200RT offers), it is none the less a physical embodiment of a 1959 motorcycle. In short, the futuristic is tempered by the technology of its era, but its futurism makes you think, it shouldn’t be, and therein lies the juxtaposition.
While still plagued by the Leaders’ inherent hot start difficulty (faced by most owners), my Leader starts readily from cold with minimal exertion on the kick start. Although Ariel saw fit to provide a choke lever protruding from the side panel to assist in cold starts, it neglected to provide any ready means of activating the tickler, and this adds to the inherent juxtaposition. Once started, suitably warmed up, the gear lever lifted into first, anticipation builds, throttle increased, clutch released and one is immediately… underwhelmed. Starting off, one is aghast by first
gear’s low ratio resulting in almost indiscernible forward progression with subsequent gear changes bringing about somewhat further dismay. Again, the juxtaposition sets in. While the Leader’s engine may be an Adler clone (17.5 HP), its weight (330 lbs/165kg dry), bulk and slower, almost train-like approach to speed reminds you that while the Leader may be futuristic, it is so within its time frame of creation. Once this is recognised, the enjoyment really begins.
“The Leader feels light and it is easily manoeuvrable, it feels sure-footed when both lightly cruising on back roads and on main, faster roads. The leading link style front forks keep the front wheel in constant road contact and is happiest when cruising at 80 km/h. While the Leader is capable of cruising at higher speeds, this is often accompanied by an increase in “buzzines”, largely felt via the foot pegs. Should one venture into the twisties overly aggressively, the centre stand is sure to ground providing an audible safety reminder that reinforces to the rider that the tyres are of square tread design – and you are pushing things. Braking is best when coupled with anticipation, commensurate throttle and gear lever response and realistic expectations – these are not disc brakes! The windscreen and integral leg shields provide excellent wind/weather protection, yet obviously the full frontal mass of both impacts on speed (more so in headwinds) and often involves frequent gear changes to suit. The Leader is most at comfort on secondary roads, nipping down to the shops or café for a cuppa, which again is fitting given the roads of its era. “In conclusion, when I was considering the purchase of my 2011 BMW, (my first new motorcycle) the salesman extolled its “innovations” (lockable panniers, adjustable headlamp to compensate for a passenger, clock, neutral light, front/rear operated brake light, small lockable storage area in petrol tank, steering lock, seat lock, etc.), I admit, I was mentally comparing all of these “new innovations” to what the Ariel Leader had…some 52 years earlier. As history too often shows, there is an inherent risk embodied in catering to the motorcycle buying public in that they (seemingly) dismay at motorcycles lacking development/foresight as equally as they do motorcycles (seemingly) ahead of their times. In as much as many Ariel aficionados (and indeed the parent company itself, BSA) looked upon the 2 stroke Leader in dismay (if not outright disdain) the 4 stroke, 4 cylinder, shaft drive prototype (not unlike the original Leader) was a portend of things to come as evidenced 25 years later by the advent of the 1983 BMW K Series.”
The Ariel Leader 4 in the National Motorcycle Museum UK.
Leader advertisement circa 1958.
ABOVE & BELOW Illustrations of the novel Leader frame and front forks.
RIGHT Trouble lamp, another option. ABOVE Turn indicators flank the headlight. RIGHT Trailing link front end gave excellent road holding. Petrol filler cap sits at the front under the hinged seat.
Rear luggage carrier. Yes, a bumper bar on a motorcycle.
ABOVE Dashboard and instruments, including the optional clock. Green light to the right is neutral indicator. BELOW LEFT Parking light sits behind the large screen. BELOW CENTRE The only visible part of the engine. BELOW RIGHT Panniers have matching vinyl inner bags.
TOP Plenty of capacity inside the dummy fuel tank. ABOVE Choke lever and petroil tap protrude through left side panel.