Almost Famous: The 1958 Ariel Cyclone

Launched in 1948, Ariel’s first parallel twins, the models KG and KH, used a 499cc engine with 63mm x 80mm bore and stroke. Designed by Val Page, the engine had two separate camshafts, one intake, one exhaust, both driven by duplex chain. The one-piece crankshaft was supported on a primary-side roller bearing and a white metal bushing on the timing side. Drive to the dry multiplate clutch (in a separate housing inside the primary) was by single-row chain. The gearbox was a Burman 4-speed.

The 6.8:1 compression KG powertrain fitted into essentially the chassis and running gear of the 350cc and 500cc Ariel singles, the “de luxe” NG and VG. The “bench-tested” KH engine, with polished ports and heads and 7.5:1 compression, became the Red Hunter 500, with red paint over a chrome gas tank and gold pinstriping. Front suspension was by Ariel’s own hydraulic fork with a rigid rear, although Ariel’s odd Anstey-link plunger rear suspension was available as an option.

Huntmaster

By the time Ariel’s management had determined the need for a 650 twin (no doubt spurred by BSA’s A10 and Triumph’s 6T Thuderbird of 1949), the company had become part of the BSA group. BSA decided to forego the cost of developing either a brand new engine or stretching the KG/KH to 650cc by the simple expedient of using its own Bert Hopwood-designed 646cc A10 engine — although the outer castings, especially the primary case, were modified as a concession to Ariel’s distinct brand.

That meant the new for 1954 model HF Huntmaster used a 646cc parallel twin of 70mm bore and 84mm stroke with a one-piece forged crankshaft with the flywheel bolted to the center web. The cylinder block and head were made of cast iron. The crank ran on a drive-side roller bearing and timing side bushing, with all four pushrods operated from a single camshaft behind the cylinders.

The disguised BSA engine drove a Burman 4-speed gearbox by a primary chain running in oil, driving a dry clutch housed in a separate compartment in the primary case. A large inspection cover held on by four screws allowed access to the five-spring clutch for adjustment. The drivetrain went into a new chassis with swingarm rear suspension and 19-inch wheels with full-width alloy hubs and 7-inch drum brakes front and rear.

Most Huntmasters seem to have been finished in that particular shade of Ariel maroon, and most came with the capacious cream-colored dual seat. Trim included Ariel’s singular take on the popular headlight nacelles, made from two steel pressings.

Cyclone

By the time the Huntmaster appeared, BSA already had a sports version of the iron-engine 650 aimed at the U.S. market, the 40 horsepower Super Flash with sports camshaft, higher compression and an Amal TT carburetor. But the semi-unit engine and BSA transmission were still housed in the old-style plunger frame. To update their sports model, BSA adopted an alloy cylinder head (but still with a siamesed intake) and dropped the new power unit into a duplex cradle frame with a rear swingarm not unlike the Huntmaster’s. This became the Road Rocket. The alloy cylinder head was revised for 1958 and the TT carb replaced with an Amal Monobloc to give the 43 horsepower Super Rocket. All BSA 650 twins received a new crankshaft with larger bearings for 1958.

The development history of the BSA models is important in the context of the Cyclone because, although BSA had adopted an alloy cylinder head as early as 1954 for their sports models, the Cyclone was fitted with an iron cylinder head to the end of its production in 1959. It’s reasonable to assume, then, that the engine specification for the Cyclone was essentially as the 40 horsepower Super Flash, but with the more modern Amal Monobloc carb instead of the Flash’s TT. In a January 1959 road test in Cycle magazine, Ariel’s Western U.S. distributor, Johnson Motors, provided a Certificate of Performance from Ariel showing that the engine had been bench-tested to 40 horsepower at 6,300rpm on a brake dynamometer. However, Roy Bacon’s book Ariel: The Postwar Models claims the Cyclone used a camshaft from the 1958 offroad Spitfire — though it also states that by 1959 the BSA sports camshaft profiles had been standardized.

What did distinguish the Cyclone was its paint finish — red and black with chrome fenders, “Western” handlebars — and Lucas type 529 taillight. At least one Cyclone I’ve seen has a small plate attached to the dash with “Cyclone” engraved, and some also have “Cyclone” on the oil tank instead of an “oil level” decal. Given the dollar value of the Buddy Holly bike, buyers of Cyclones should check provenance carefully.

Cycle road test

As noted previously, Cycle conducted a road test of the Cyclone that appeared in the January 1959 issue. While the review has to be taken in the context of the time, the editors’ praise for the Cyclone was gushing. Maneuverability in traffic was pronounced as “really astonishing” and its brakes “powerful.” And while the rear brake required “a harder pressure than normally expected,” it was “absolutely reliable and fade proof.” They also liked the “high efficiency” of the lighting equipment, which “enables the rider to maintain high cruising speed at night.”

Cycle also liked the Cyclone’s “ton-plus” performance and its ability to chug along at 19mph in fourth gear with no chain snatch. Shifting up or down was “most satisfactory” and the clutch lever was a “sheer joy to operate.” Road holding gave “the sensation of safety … even during sharp cornering,” and they found it unnecessary to even touch the steering damper.

Also appreciated was the optional full rear chain enclosure, which they deemed “a sound investment.” They also considered the tan “Vinyde” faux-leather dual seat to be “very roomy” while providing “plenty of comfort for long rides.” Overall, Cycle concluded that the Cyclone “represents a fine investment whose dividend will be thousands and thousands of miles of trouble-free and enjoyable motorcycling.”

Garth Clare’s Cyclone

The provenance for Garth Clare’s Cyclone is pretty much irrefutable. It checks all the right boxes. It has an HC8 engine from the correct number sequence, the red/black paint scheme and the correct Lucas taillight. Clare has also had the engine number checked by Sandy Stewart of the Ariel Owners Motorcycle Club: Out of 175 “definite” Cyclones produced and a further 76 “possibles,” Clare’s machine is number 8 in sequence of the “definite” machines. For the record, the Holly bike was number 3. Clare’s Cyclone was shipped from Ariel’s Selly Oak, Birmingham, England, factory on Dec. 4, 1957, bound for BSA New York, the East Coast distributor. (Holly’s shipped on Dec. 17.) Clare can also trace the Cyclone’s ownership back to 1971.

Clare bought the bike as a basket case from fellow West Coast British Motorcycle Owners Club member Wade Edwards, who had imported it — or at least what there was — from the States in 2010. The Cyclone was missing the seat, fenders, center and side stands, handlebars, levers, cables, switches, footpegs, headlight, horn, headers and mufflers, and the rear chaincase! But the important matching number parts — the engine, transmission and frame — were all there, as well as the gas and oil tanks, toolbox and headlight nacelle.

“It arrived in Canada in a mostly disassembled state, with the engine having suffered obvious serious mistreatment,” Clare says. “The frame, too, had been doctored to remove the dual seat. My suspicion is that had been used as a scrambler. I purchased the components in 2011 and have restored it over the last four years.”

When Clare started into the engine, he found a horror story: the sludge traps and crankshaft oil-ways were clogged with solid carbon. “There was evidence of an earlier rebuild,” he says, “but they did not clear the crankshaft oil sludge trap and I think the engine immediately seized, fortunately without breaking anything. I suspect the mechanic was unable to diagnose the problem, gave up and eventually sold the motorcycle. It’s very difficult to remove crank plugs.”

The gearbox had also suffered some trauma — as a result of the engine seizure, Clare suspects. “I stripped it down and replaced the bearings, bushes and seals, but when I was hand testing it there seemed to be a rotational ‘tight’ spot,” he says. The culprit turned out to be a bent layshaft. A good used replacement was sourced from Ariel specialists Draganfly in England.

Clare credits Draganfly as one of his main sources of parts, as well as the Ariel Owners Club, Armours, Walridge Motors and eBay, where a set of footpegs as well as parts for the almost unobtainable fully enclosed rear chaincase popped up. “The fully enclosed rear chaincase consists of four separate parts that are very rare,” Clare says. “I managed to gather parts gradually, and count myself lucky to have acquired all four bits. eBay was surprisingly useful.”

However, the fuel tank and nacelle had severe crash damage, and “were beyond my skills to repair,” Clare says. “Even professional help of this kind is rare.” Clare found John Epp of Iron John’s Vintage Motorcycles in Cultus Lake, British Columbia, Canada, who was able to repair and restore the two items. “I’m thrilled with the result,” Clare says.

With the bike reassembled and running, Clare ventured out on the street, but quickly ran into another problem. “The bike was repeatedly jumping out of second gear,” he says. Stripping the gearbox again, Clare found excessive wear in the selector fork fingers and the layshaft second gear dog teeth. Clare was able to repair the selector by brazing, but couldn’t find a replacement second gear cog. Clare credits British Motorcycle Owners Club member Lyle Whitter with guidance and help with many aspects of the restoration, especially offering advice and loaning tools — and finding a replacement cog in his stock of Ariel parts! “I reassembled the gearbox, and, presto, problem solved! Such is the nature of a project like this,” Clare says.

Fewer than 300 Cyclones were built, though the precise number is difficult to determine. It’s known that some Huntmasters were also fitted with the HC8 high-compression engine, and converting a Huntmaster to Cyclone specification (especially externally) wouldn’t be beyond the skills of an unscrupulous restorer. This one, however, is the real thing. Oh boy! MC