Harley-Davidson Model 17 FHAC 61CI Eight-Valve History
It may seem unlikely today when the roles are presently reversed, but over a century ago HarleyDavidson was a smaller company than Indian, which manufactured 32,000 motorcycles in 1913, exactly double the 16,000 made by Harley.
Sold through a worldwide network of more than
2000 dealers, the Wigwam’s products took almost
40% of a booming US market contested by dozens of different manufacturers. This seemed to support Indian management’s belief that racing improved the breed and sold bikes – a belief supported by a comprehensive factory competition programme headlined by their iconic, and successful, eight-valve V-twin board-track racer, which debuted in 1911 and immediately became the bike to beat.
By contrast, Harley came late to the racing game, fielding its first factory team only in July 1914, by which time other makes, especially Indian and Excelsior, had established a considerable advantage. But earlier that year, Harley had hired Bill Ottaway from Illinois-based Thor, where he’d designed record-breaking bikes that also won races in the fast-developing board track racing scene.
Working as H-D’s racing engineer and de facto competition boss alongside company co-founder and chief engineer Bill Harley, Ottaway was first able to enhance the performance of H-D’s so-called pocketvalve IOE (intake over exhaust) V-twin racer based on its production models, with just two valves per cylinder, to the point that Harley’s first factory rider Red Parkhurst won the 1915 National Championship, and took a series of hard-won victories against Harley’s hitherto dominant rivals.
But Ottaway’s longer-term objective was to create an allnew 61ci/1000cc racing engine for Harley with four valves per cylinder, that’d be capable of sustaining the Motor Company’s new-found success on the faster mile-long and even bigger board racing tracks, and could also form the basis of a 30.5ci/500cc single-cylinder motor for use on the increasingly popular half-mile dirt-tracks. Indian designer Oscar Hedstrom – who coincidentally had also worked with Thor – had already proved the advantages to be gained in terms of valve reliability (a key issue back in those early metallurgical days), enhanced combustion and improved breathing by the use of paired valves, although
at first Harley-Davidson was unable to grasp the concept in practical terms. Following a series of setbacks, Ottaway and Harley enlisted the services of Britain’s pioneer in four-valve engine development, Sir Harry Ricardo, who, after some weeks spent in the Milwaukee factory in 1914, perfected the design which first appeared in competition two years later, with immediate success.
Officially designated as the Model 17 FHAC Eight-Valve Oval Port racing engine, this V-twin design featured Harley’s classic 45º cylinder angle, with each pair of parallel valves set at 90º to its partners, and mounted on the same diecast crankcases employed on Harley’s CA pocket-valve racers. The 35/16in x 3½in (approximately 84x89mm) 998cc motor’s air-cooled cylinders with integral heads were lightly finned, with a pair of long, slender pushrods rising in parallel from the crankcase, and operated by a single roller-bearing cam. Coil valve springs were used, with a single 11/6in (27mm) Schebler Type H (for Harley) racing carburettor set between the cylinders in time-honoured Harley style, feeding all four intake ports. Each cylinder had twin separate exhaust pipes exiting its exhaust ports, with those mounted to the rear cylinder’s rearward-facing ports shorter than those exiting the front pot’s forward-facing exhaust ports – all of them oval in shape.
Frequently, the bikes were run in the USA and in the UK at Brooklands without any exhaust pipes at all, and the lack of cylinder finning to any great extent denoted the predominant use of alcohol fuel. This was stored in the right half of the slender, handsome-looking tank, with the oil supply fed by gravity from the left half, assisted by a hand pump set in its side. The oil system was total loss, with the mechanical pump originally cast into the body of the aluminium timing-case cover, though from 1917 onwards a separate oil pump was fitted. The single central spark plug per cylinder was fired by a Bosch magneto, which Harley began fitting to its bikes only once hostilities with Germany had ceased at the end of the First Word War in 1918. This gave the early-vintage Harley roughly the same performance, both on acceleration and top speed, as the Daytona 200-winining double overhead camshaft 500cc Manx Norton singles of 35 years later.
The Harley’s three-speed countershaft gearbox with footoperated dry clutch and all-chain (primary and final drive) transmission, with a hand shifter on the left of the fuel tank, also featured a right-side kick-start, although the factory bikes ran such high compression that they often had to be tow-started into life behind a car.
The Model 17’s tubular steel single-loop frame with a duplex engine cradle varied in wheelbase down the years from 53.5in/1360mm to as long as 60in/1525mm, depending on the length and type of the track and the need for enhanced stability at speed. It never employed any rear suspension (even though the good-handling Flying Merkel already successfully featured this), and no front brake, with just a single six-inch/152mm expanding band drum stopper at the rear. Most earlier eight-valve Harleys were fitted with a so-called ‘truss fork’ derived from the Flying Merkel’s design, an unsprung strutted girder fork later replaced by Harley’s trademark Springer fork with leading link operation of the twin springs, and a forwardmounted scissors-style friction damper. Harley’s Springer – aka Castle – fork worked so well that even the pretty stingy George Brough paid the Motor Company a royalty to fit them on his Brough Superiors.
The factory Harley-Davidson Racing Team’s legendary Wrecking Crew squad of riders made the most of what Ottaway’s ingenuity had given them. Established in 1916 and captained by Otto Walker, it consisted of up to a dozen riders – though usually only five or six in any one race – who’d come up the hard way, racing week-in, weekout, all around the country. Thanks to the FHAC engine’s outstanding performance, they demolished the Indian and Excelsior-led opposition to the point that Harley registered a clean sweep of National Championship titles in 1921 – eight in total, ranging from one to 300miles, and all bar the one-mile and five-mile titles achieved at record speeds. Indeed, in February that year Otto Walker won the 50-mile race held on the Fresno, California board track for Harley-Davidson at an average speed of 101.40mph – the first motorcycle race anywhere in the world to be won at an average speed of over 100mph.
According to a memoir he wrote in the late 1930s, the modest Ottaway put Harley’s success down to a combination of technical features. “The source of the ‘soup’ in these eight-valve jobs was due to many aspects,” he wrote. “[These were] the cam-action, valve timing, compression ratio, the eight-valve pent-roof combustion chamber configuration, light aluminium-alloy pistons
(we were considerably in advance of other countries in the pioneering of alloys for piston material in those early days), lightweight machines, and our flywheels were all hand-balanced and polished to relieve stress.”
However, Harley-Davidson’s rampant success was also due in no small part to Ottaway’s skills as team manager, which included detailed organisation of the entire effort, and extensive preparations to save time at pit stops.
Apart from his established means of instructing the riders on race tactics via flag signals, the mechanics were forewarned when a rider slowed to stop for refuelling via a telephone line which ran along the side of the track to a lookout, quick-release axle nuts facilitated 10-second wheel changes, along with specially-designed oil and fuel tanks with extra-large orifices which speeded up replenishment – a separate tube to let the air in the tank to escape was yet to come though! Pit stops included a clean pair of goggles for the rider and a refreshing drink of water or orange juice, and after extensive practice, Wrecking Crew riders would stop for under a minute to accomplish all this – anything up to two-thirds shorter than their rivals.
But this and the technical excellence of the bikes meant Harley was too effective for its own good, and after that clean sweep in the 1921 season Harley-Davidson management decided to withdraw from racing officially in the USA – a decision taken in the light of slumping sales, down to 12,000 bikes in 1923, though Harley had overtaken Indian (which sold 8000 units) to become America’s number one.
But the company continued to manufacture new FHAC eight-valve bikes and engines as well as spare parts for riders to continue racing them on their own account, with no direct factory involvement, as well as to ship to its overseas distributors. Italy was the scene of some of Harley’s first and greatest international victories, and it was also one of the American firm’s largest export markets post-First World War, with a large and well-established distributor in Rome which even went so far as to produce its own locally-built model, known as the Harlette. Built with the approval of the parent company and finished
in the in the same khaki and red colours as the bigger bikes, this was not a Latin strumpet, but a small-capacity run-around powered by an Austrian Puch engine. But the company’s main concern was the V-twins, and many hundreds of these were imported as Italy’s hell-for-leather modernisation unfolded in the 1920. The long, straight, fast roads of Italy’s industrial north were ideally suited to the large-capacity American bikes, akin as it was the US Midwest – Harley’s heartland.
To promote sales, Harley-Davidson Italia imported a limited number of factory racers, including two of the Wrecking Crew’s eight-valve V-twins. The bikes were practically as successful in Italy as in the USA, principally in the hands of Amedeo Ruggeri who, while formerly a member of the Indian ‘Wigwam’ fraternity, achieved even greater renown once he switched to H-D for the 1922 season. That year he won the gruelling Milano-Napoli single-stage marathon on a Harley eight-valve, then followed that up with victory in the inaugural Italian
GP at Monza, averaging 104.323kph/64.82mph for the 250-mile/400km race round the parkland Autodromo, to lead three other Harley riders across the line.
Equally successful on an eight-valve Harley was British rider Freddie Dixon, a hard-headed, canny operator who was as intelligent as he was brave. Dixon tuned and raced his eight-valve Harley successfully at Brooklands, sharing it with an Indian which he ran as both a 500cc (with one cylinder blanked off ) and occasionally a 1000cc bike, but it was on the Harley that he set a new official World Land Speed Record for motorcycles at the Bois de Boulogne Speed Trials in Paris in September 1923, at 171.80kph/106.75mph.
Ottaway updated the FHAC eight-valve engine for 1924, retaining the same crankcases and engine bottom half, but now with proper cooling fins on the redesigned cylinders and heads. The valve-train was simplified in pursuit of higher revs, with revised valve timing and longer exhaust pipes aimed at enhanced scavenging. This kept Harley riders at the front of the field in racing sanctioned by the newly-formed AMA, but with the demise of the board tracks thanks to inadequate maintenance by greedy promoters, combined with the increasing value of the land they were built on for housing and industrial purposes, as well as the effects of the Depression in the wake of the Wall Street crash, Harley management decided to discontinue making both eight-valve engines and complete bikes. In fact, though, as Bill Ottaway noted in his memoir: “We still had quite a backlog or stock pile of these machines and engines… So the factory decided to sell or give them away to a number of their overseas dealers. My records show that about six of these machines were shipped to Australia in that period. At least 12 machines and/or engines were allocated to New Zealand. Almost the entire remainder were sent to Scandinavian countries, but a small number were split up between France, Switzerland and the Argentine. Some satisfaction was derived by me when I learned that many of these dealers had used these eight-valves with success in competition in their own country.”
That satisfaction was well deserved, for it is widely recognised that the eight-valve racer was one of Harley’s crowning achievements, a design which set the Motor Company at the leading edge of motorcycle design, and made good use of the ever-advancing technology of the era.