1960 Ariel Arrow 250
Engine: 247cc air-cooled 2-stroke parallel twin, 54mm x 54mm bore and stroke, 10:1 compression ratio, 16hp @ 6,400rpm
Top speed: 70mph
Carburetion: Single 7/8in Amal 375 Monobloc
Transmission: 4-speed, chain final drive
Electrics: 6v, coil and breaker points ignition
Frame/wheelbase: Pressed steel spine frame/ 51.2in (1,300mm)
Suspension: Trailing link w/twin shocks front, twin shocks rear
Brakes: 6in (152.4mm) SLS drum front and rear
Tires: 3.25 x 16in front and rear
Weight (dry): 275lb (125kg)
Seat height: 28.5in (724mm)
Fuel capacity: 3.2gal (12ltr)
Price then/now: £171 ($477, est.)/$2,500-$8,000
Ask pundits why the British motorcycle industry collapsed in the late 1960s and most will point to management’s failure to innovate and modernize in the face of increasing foreign competition. If it had just been that simple.
Innovation is a tough row to hoe. There’s no question the British industry had the talent and the resources to come up with new designs. What held them back in many cases was not their own inertia, but the conservative nature of the motorcycle-buying public and an unwillingness to accept designs that broke the mold.
Edward Turner knew this. His 1937 Triumph Speed Twin was expressly designed to look like a typical twin-port single of the period, easily the most popular type of bike on British roads. The Speed Twin won by looking right while offering better performance and smoother running.
Meanwhile, Valentine Page, perhaps the most prolific of British motorcycle designers, was more focused on engineering fundamentals than flash. Learning his trade at engine supplier J.A. Prestwich, Page was the Yin to Turner’s Yang, and they frequently worked on and improved each other’s designs — though rarely at the same time.
For example, after succeeding Page as chief designer at Triumph in 1936, Turner repackaged the company’s line of overhead valve 4-stroke singles with upswept pipes and show chrome to create the Tiger 70, 80 and 90. And it took the Turner touch to turn Ariel’s plain-Jane sports model VH — another Page design — into the crimson-and-chrome Red Hunter.
Similarly, Page re-engineered Turner’s Square Four in the post-war years into the sophisticated superbike of its day. Page was also responsible for the 1935 6/1, Triumph’s first unit construction 650cc parallel twin (Motorcycle Classics May/June 2013). But like most of Page’s designs it was more prosaic than pretty, and when Turner took over as chief designer at Triumph, he quickly canned the 6/1 in favor of his own parallel twin design.
So when charged with bringing Ariel’s product lineup to date in the mid-1950s, it’s not surprising that Page produced a marvel of modern engineering that looked like something built from a constructor set.
First the Leader
Market research should be easy: You ask people what they want, and develop a product that meets their needs. But as Edward Turner knew — and Ariel was about to find out — what buyers say they want and what they’ll actually buy may be two different things. The annals of well-researched products that missed the market read like a litany of failure: the Ford Edsel, New Coke, Aermacchi’s Chimera (Motorcycle Classics March/April 2014) … and perhaps the Ariel Leader.
And the stakes were high. Though Ariel was part of the BSA-Triumph group, the Selly Oak factory enjoyed relative autonomy. In committing to their new design, Ariel decided it would drop all other models from its range, including the Square Four. From 1958, the company would produce just one model: the 250cc Leader.
The Leader represented a radical rethink of what a motorcycle should be and do. No doubt influenced by the hundreds of thousands of imported scooters flooding the U.K. motorcycle market, the decision was made that the Leader’s mechanicals would be fully enclosed behind molded body panels. That meant the chassis and drivetrain could be engineered for functionality and production efficiency rather than just looking good.
Page approached the design from first principles, borrowing methods and techniques from the auto industry. The Leader’s beam frame would be made from steel pressings welded together, eliminating the labor-intensive brazed lug and steel tube frame. The front fork would also be pressed, avoiding the expensive machining required in the production of a telescopic fork. And the new power unit would be made using pressure die casting rather than the sand cast process commonly used at the time.
Page’s engine was unconventional, too. Though other British companies had produced 2-stroke twins, almost every other 250cc British motorcycle made at the time was a 4-stroke single. Borrowing technology from the German Adler MB250, the Leader’s engine was a purpose-designed piston-port 2-stroke twin of 54mm x 54mm bore and stroke dimensions (same as the Adler, and repeated in Yamaha’s YDS-1), with the pistons running in heavily finned, deeply spigoted cast iron barrels topped with light alloy cylinder heads. A single 7/8-inch Amal Monobloc type 375 carburetor fed the engine with 25:1 premixed “petroil” fuel. Alloy connecting rods with roller bearing big ends ran on two separate built-up crankshafts that were bolted together during assembly and “timed” at 180 degrees by a keyed taper.
The crank assembly fitted into die-cast cases with the primary drive and transmission cast in unit. Drive to the clutch and 4-speed gearbox was by chain. The complete drivetrain was suspended from the beam frame by a cast lug behind the barrels that also doubled as the air intake and carburetor mounting. The frame wrapped around the rear of the power unit, and also carried the rear swingarm pivot. The swingarm itself carried mountings for the full-enclosure chain guard, and was controlled by a pair of Armstrong spring/damper units bolted to the rear frame.
There was no triple tree at the front. The head stem was brazed into a steel casting that also carried the fork legs, which contained a trailing-link suspension controlled by Armstrong shocks. The whole front end arrangement owed more to contemporary scooter practice than motorcycle convention. More familiar, though, were the 16-inch WM2 wire wheels, both fitted with 6-inch single-leading-shoe drum brakes.
The finished Leader did look more like a big-wheel scooter than a contemporary motorcycle. The full-enclosure bodywork included a dummy gas tank that actually contained a luggage compartment, with the actual fuel cell being a rectangular steel tank under the seat. An optional full windshield could be fitted, together with hard luggage, turn signals and a clock mounted in a full dashboard. The rear bodywork hinged upward (after releasing the muffler stays) to give access to the rear wheel. Think Honda’s PC800 Pacific Coast, perhaps …
Like the PC800, the Leader failed to set sales on fire. A supremely practical motorcycle, especially compared with what was available at the time, it combined the best aspects of both a scooter and a motorcycle. Its 16 horsepower engine gave it a top speed of around 70mph, while its full-size wheels made for confident handling.
Test reports concluded that the Leader “was comfortable, went well, handled nicely and braked smoothly.” Most criticism was aimed at the bodywork. The luggage compartment lid was insecure, and the side panels difficult to remove for routine maintenance. That said, the Leader still won “Machine of the Year” in a Motor Cycle News ballot, and while it proved popular with police forces, its innovative features failed to inspire the British bike buyer who preferred the sportier look of a traditional 4-stroke single or twin. The Leader also suffered as sales of all motorcycles were hit by another innovative vehicle also launched in 1959: the Austin/Morris Mini.
Whether Ariel had always intended to build a “sports” Leader, or whether the decision was a response to disappointing sales, a new stripped-down version of Page’s design was announced at the end of 1959. The Arrow was mechanically identical to the Leader but was missing its bodywork and featured a new “gas tank” with ears extending forward to carry the headlight. The Leader’s deeply valanced front fender and fully enclosed rear chain guard were retained. The Arrow was lighter, and while still unconventional, sportier looking. The lower weight also translated into livelier performance, as road testers found out.
The Arrow would “step off the mark a little more briskly,” cruise comfortably at 60mph and return 60mpg. Below that speed the handling and suspension were good, but above it, the Arrow “began to pitch and weave.” Fast bumpy corners had to be treated with a degree of respect.
The Arrow used the same 6-inch single-leading-shoe brakes as the Leader, but now with iron hubs as a result of some cracks appearing on Leader alloy drums. Braking was “just about adequate” for a solo rider, said testers, requiring “heavy pressure” to stop from 70mph. Adding a passenger “was definitely too much for them.” An upgrade to a 7-inch brake was recommended. In spite of that, the Arrow still won Motor Cycle News’ “Machine of the Year” for 1960.
For 1961, both the Leader and Arrow got new squish-band cylinder heads, and new iron brake hubs (though still only 6-inch diameter) that included a new lever/cam for improved efficiency. And that same year, a Super Sports version of the Arrow was announced, with a larger carburetor (a 1-1/16-inch Amal 376 Monobloc), 10:1 compression and 20 horsepower at 6,600rpm. The extra power pushed top speed to 75mph but still returned 68mpg during a 500-mile test.
With the dummy “gas tank” finished in gold, and with red handgrips, the Super Sports quickly became known as the “Golden Arrow,” and won Machine of the Year for 1961 — three years in a row for Ariel.
The Leader and Arrow continued with minor changes through 1964, when a 200cc Arrow joined the range to take advantage of a cheaper insurance bracket. When production ceased in 1965, just 36,000 Leaders and Arrows had been produced over seven years. For comparison, Vespa produced 350,000 units of just one model (the 150/150GL) in roughly the same period. More ominously, in 1964 an Ariel Leader cost around £225 ($628), while a new Mini was less than £500 ($1,400) …
What might have been
Valentine Page’s last design for Ariel showed his radical thinking and anticipation of future trends. It was intended as a replacement for the Square Four, a luxury tourer with an under-stressed engine designed for production efficiency and easy maintenance.
In place of the Leader’s 2-stroke twin, Page’s new design called for a fan-cooled 700cc inline 4-cylinder engine mounted along the frame and laid flat, with the cylinder heads on the left. Power fed through an engine-speed clutch to a car-type gearbox with shaft drive to the rear wheel. Electric starting was included. Page had effectively anticipated BMW’s K100 by 20 years!
One prototype was built, which now resides in the National Motorcycle Museum in Solihull, England.
Joe Li’s Ariel Arrow
Joe Li of Vancouver, British Columbia, Canada, is a British bike fan with a fondness for the café racing days of the 1960s. As well as the Arrow here, Joe rides a BSA A65 Lightning café racer. So why did he set out to find an Ariel Arrow?
“I’ve been wanting to get a 2-stroke motorcycle, but I didn’t want Japanese,” Li says. “I watched a 1964 movie, The Leather Boys, and in it was an Arrow. It really gained my attention. It just looked so different.
After deciding he wanted one, Li spent months scouring U.K. motorcycle magazines and searching eBay. He eventually found an Arrow in Wisconsin, but there was no title with it. Finally, an Arrow turned up at a U.K. dealer, Pembrokeshire Classics. Though he would have preferred the Super Sports “Golden Arrow,” Li decided to buy it anyway and imported it directly into Canada.
As purchased, Li’s Arrow was a solid rider, having been restored sometime in the past, leaving him to enjoy riding it rather than wrenching on it. “It is very light,” Li says, “and the center of gravity is so low. So it’s very different.”
Li also noticed the different engine torque characteristics versus the more familiar 4-stroke, observing that many riders trying a 2-stroke for the first time would stall it on takeoff. “When I first started it and tried to get moving, I stalled it. But I got used to it right away.”
Having got the start organized, the next issue was stopping. “When I first got the bike, the front brake was almost useless,” Li says. However, he discovered that the front wheel and the brake lever at the front drum had been installed the wrong way around. Refitting it correctly and optimizing the cable routing improved things considerably. “Actually, it’s not that bad if configured correctly,” Li says.
The suspension was criticized in period tests, and Li seems to agree that it has its limitations. “It would be better if the front end was a bit stiffer,” Li says. “It’s a bit springy, so I don’t push it very hard when turning. But at the same time, because it’s so light, it’s so easy to make turns.”
One problem Li encountered with the Arrow was when changing the transmission oil: There was a slurry of aluminum dust in the oil. Suspecting a bearing issue, Li stripped the gearbox and discovered the first gear pinion had been installed backwards and was grinding against the cases. Fortunately, the damage was minimal, and he was able to reassemble the gearbox without any further remedial work — and with the pinion the right way around!
This exercise also highlighted one of the Arrow/Leader’s design features — the gearbox outer shell complete with the gears can be easily removed from the right side of the transmission case after dismantling the clutch.
It’s not widely appreciated that the Arrow engine had considerable tuning potential, yet it did, as Herman Meier demonstrated in preparing an Arrow racer for the 1960 Isle of Man Lightweight TT. Michael O’Rourke brought the Arrow home in seventh place, beating Luigi Taveri’s MV Agusta! Li wants to build a racing Arrow like the TT bike, based on information gleaned from a 1960s issue of Motorcycle Mechanics magazine.
“I have a spare engine, and I’m collecting parts,” Li says. In the plans are getting the crankshaft reconditioned and upgraded by Draganfly Motorcycle as well as improving cylinder porting and increasing compression. “That one will be a racing version,” Li says, “but this one I will keep as original.” MC
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