Goodbye Sportster, Hello Sportster S

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In 1952 Harley-Davidson rolled out the unit-construction K-model (and its KR racer counterpart) to compete with lightweight British machines of the era. (Jeff Allen/)

One day in the fall of 1959 I sat at the phone with the college newspaper’s classifieds before me. I had marked two bikes for sale, the first a BSA D1 Bantam 125, and the second an ex-military Harley-Davidson WD. Money from my summer job made either affordable—the BSA at $140 or the Harley at $125.

When I call a number, I always imagine a rising curve of probability that noses over after three or four rings. I dialed the WD owner: Nobody home. Would my life have been different if he had answered? Did I miss out on an alternative universe? Stompin’ shoes? The Death Valley Tour, with sightings of “Dot” on her pink Harley? A stylish flattop haircut, preserved years past its fashion peak?

Before the Sportster, the K Series

The flathead configuration of the K series eventually gave way to OHV. (Harley-Davidson Archives/)

Tasked by the British Board of Trade with winning hard currency through overseas sales, in the later 1940s English motorcycle makers invaded the US market, and many US riders loved those bikes’ lighter weight, greater responsiveness, and acceleration.

Harley responded with an arguably revolutionary update of its 45-inch flathead—the unit-construction K series, appearing in 1952. But in flathead configuration, 45 inches wasn’t enough to compete with the same displacement in an overhead valve (OHV) design like Britain’s “export twins,” so Harley punched the K bikes out an additional 10 cubes.

Those engines had the four separate, geared-together cams that had come into being in 1929—the same four separate cams that powered Harley’s Sportster-derived dirt-track XR750 to so very many national championships between 1972 and 2008. The idea of one cam per valve may have come from the early 1920s, when Harley executives touring England would have seen Velocette and others employing such systems. A long previous tradition in US motorcycling had been to use as little valve mechanism as possible, often resulting in both valves being operated by a single cam lobe, facilitated by locating the tappets the proper number of degrees apart—the lobe separation angle of later moto-lingo. But when OHV engines came to 350cc dirt-track racing and doubled the loads transmitted from cam lobe to tappet, the one-cam-per-valve concept was necessary.

When the 55-cube K-model still did not make Harley “King of the Night,” the basic concept was further upgraded from flathead to OHV (just as the Big Twin had been, starting in 1936); this gave birth to the 883cc Sportster in 1957.

The new configuration gave birth to the 883 Sportster as we best know it. (Flickr/)

The Sportster’s design evened the score by being capable of much more development. When AMA’s racing formula changed to straight 750cc effective in 1970, Harley developed its first iron-head OHV XR racer for that year, updated for 1971. The late, great Calvin Rayborn used this bike to humble England’s top riders in the Transatlantic Match Series roadraces.

The Sportster Evolves

Iron conducts heat poorly. Harley’s Big Twins were already using aluminum heads, and it was urgently time to do the same with the XR. It acquired an all-aluminum top end in 1972 and won its first Grand National Championship that year—still with the four separate, geared-together cams.

Flatheads like the previous KR racers are simple, and since their cams and tappets are down beside the crankshaft, those parts are well lubricated. Lacking the extra weight of pushrods and rocker arms, they could rev easily without valve float. But they lacked two critical things:

1. OHV engines had a compact combustion chamber of the lowest surface area, with both valves and combustion chamber positioned directly above the piston. <a href="https://www.cycleworld.com/flat-head-motorcycle-engine-examined-kevin-cameron-top-dead-center/">Flathead</a> combustion chambers needed extra volume, situated beside each cylinder, in which to locate their valves, stems downward. The side-chamber’s extra volume made it impossible to achieve both the high compression ratios that gave OHV engines their higher torque, and the high flow that gave OHVs more power.<br/>
2. Mixture flowing from a flathead’s carburetor had to negotiate a twisting path—up to the underside of the valve, across the “valve shelf” to the cylinder, then downward at 90 degrees to follow the piston, descending on its intake stroke. Less restrictive and shorter was the flow path in an OHV design—down to the valve, into the hemi combustion chamber, and downward to chase the moving piston. That’s why OHVs were allowed only 500cc of displacement to the 750cc of the <a href="https://www.cycleworld.com/2016/02/22/motorcycle-four-stroke-engine-valve-arrangements-kevin-cameron-insights/">Harleys</a> and Indian flatheads when both types were racing together.<br/>

Harley persisted with those four separate geared cams in the Sportster even through the coming of noise legislation. The latest Big Twin drives its single four-lobe camshaft by a quieter chain, not by clickety gears. (English designer Bert Hopwood, who drew export twins for both BSA and Norton, called Triumph’s dual, two-lobe gear-driven cams “rattlers.”) Need more accurate tooth forms to suppress noise? Slide those costly Swiss gear grinders into the line right here. Harley paid a real price to keep Sportster as it was, rather than radically change it.

Changing Markets, Changing Perceptions

A big part of that price was the sidelining of Harley-Davidson from the high-performance scene. Yes, I know there is no other product line so well supported by the aftermarket. But it was a blow to the Sportster and also to the English-bike scene when any kid with $999 of grocery-store bag boy income could roll out of a Kawasaki dealer in 1970 on a stock 500 two-stroke triple that could blow just about anything down. Moreso when two years later the 500 became a 750. This was a permanent changing of the guard.

The Ironhead Sportster engine was replaced by the Evo motor in Sportsters beginning in 1986. (Harley-Davidson Archives/)

That was the end for Harleys as King of the Night. There was only one way to fight back—by ignoring the performance scene. High-performance bikes were now dismissed by Harley riders with the contemptuous term “crotch rockets.” Harleys were above all that. They were cool. They were Harleys.

Yet something had been lost. As far as the derided rice-riders were concerned, Harleys after 1970 were for posers. They had become haberdashery for the fashion-conscious. Roller cranks, air-cooling, pushrods, 45-degree cylinder angle. Commit the lore to memory, pass the exam, and become a member. Buick had its portholes, Pontiac had chrome hood and trunk stripes. Recognition!

All the same, change had to come. It’s not easy to make a composite of 1924, 1929, and 1957 designs pass contemporary emissions standards. And it’s a lot to ask of riders that they tolerate substantial vibration, behind-the-times performance, and the constant siren songs of more-up-to-date competitors. Trying to make a motorcycle business by selling mainly to financially competent older bearded males is swinging more than two bats.

Old Shakespeare has Macbeth say, speaking of assassination, “If it were done…then ‘twere well it were done quickly.”

The Sportster as it has been cannot gradually evolve into a modern bike easily capable of meeting sound, emissions, and the many criticisms that attend its time-honored features. It has done a fabulous job of survival against all those opposing forces. Vacuum tubes were an essential step in the development of electronics, but they could not evolve into millions of transistor switches packaged onto a fingernail-sized silicon chip. Understand the traditions, embrace the future.

The Sportster is dead. Long live the Sportster S.

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