Putting a motor on a bicycle seemed like a logical idea from the early days of steam engines.  The problem was getting the engine small enough to fit on a bike and powerful enough to move it.  When that first happened still isn’t clear, but the earliest known attempt is pictured in an 1818 drawing of a steam-powered “Velocipedraisiavaporianna” being tested in Paris’s Luxembourg gardens.  In 1869, both a French team and American Sylvester Roper successfully built “steam velocipedes” that could go faster than a horse.

However, there were some problems with the steam-powered bikes.  they didn’t have much power, for one.  For another, they had a tendency to explode now and then.  And even at their best, you had to continuously add water and coal into the hissing, smoking engine between your legs.  Inventors looked for other approaches.  For example, the “Cynosphere,” invented by M. Huret of Paris in 1875, was powered by two dogs running on the wheels.

Finally, in 1876, the internal combustion gasoline engine came into being, thanks to N.A. Otto of Germany.  Nine years later, his former assistant, Gottlieb Daimler, fathered the first modern motorcycle.  Not that it was perfect – the spark plug had not yet been invented so to ignite the gas and air mixture, Daimler provided a Bunsen burner to heat up a metal tube that extended into the engine’s cylinder.  The problem of course was that the flam occasionally blew out in the wind.  worse, it would occasionally catch the rider’s pants on fire or, in the event of dumping the bike, ignite spilled gasoline.  Then came 1895, a year that brought the twin miracles of electrical ignition and inflatable tires.

Motorcycles began evolving away from being merely bicycles with motors strapped to them.  In 1901, a French company designed a motorcycle in which the engine was not just a clip-on, but an integral part of the design.  The designers were so confident that their motor would dependably propel the cycle that they even left off the bicycle pedals.  This design was the true forerunner of the modern motorcycle, the one the world copied. . . including some young guys in a shack in Milwaukee.

In 1901, Arthur Davidson, a twenty-year old pattern maker, teamed up with twenty-one year old draftsman named Bill Harley.  Inspired by the European motorcycles, they decided to tinker after work hours on their own design.

The two partners recruited a second Davidson brother (Walter, a railroad machinist) and then a third (William, a toolmaker).  Rounding out the team with ideas and advice was a friend named Ole Evinrude (who later went off and started his own company that made Evinrude outboard boat motors).

Needing a place to work, the Davidson boys convinced their father, a cabinet maker, to build a shed in their backyard.  They put together a two-horsepower engine from scrounged scraps (including a tomato-can carburetor) and attached it to a bicycle.  Eventually they worked out the bugs and began tooling around town at 25 mph on motorized bicycles, amazing the citizens and scaring the horses.  Pretty soon, people started asking if the bikes were for sale.  The company sold three motorcycles in its first year.

The after-hours business grew slowly.  From three motorcycles in 1903, the company increase its output 66 percent the following year, assembling five motorcycles, and then again 60 percent the following year, making eight.

This dizzying growth curve convinced the partners to build a new, 28’ x 80’ headquarters next to a rail spur.  Unfortunately, they discovered that they’d built it dangerously close to the track.  Rather than dismantle it, they got together a dozen of their huskiest friends and had them lift the building a legal distance away.  (The company headquarters still stands on this site, a safe distance from the tracks.)

Meanwhile, the partners decided they needed some capital so they could quit their day jobs.  They turned to another Davidson, who the boys called their “honey uncle” because he was a beekeeper, and borrowed enough to get serious about manufacturing their bikes.

Ironically, Harley’s first model was designed to be unobtrusive and quiet.  The partners had decided that people hated the noise and flash of the new contraptions, so William designed a grey motorcycle and effective muffler.  The result was dubbed “The Silent Grey Fellow.”  While the company sold all they could make, the silence was short-lived.  It turned out that motorcyclists liked making a disturbance.

In 1907, when annual production was up to 150 units, William Harley accidentally created Harley’s distinctively rough staccato “potato-potato” engine sound.  It was the result of taking a fairly inept design shortcut while trying to increase engine power.  Rather than designing a two-cylinder engine from scratch, he merely welded a second cylinder to his one-cylinder design, using a forked connecting rod to join both pistons to a single crankshaft “throw.”  The result was an engine that ran rough and produced an excessive amount of vibration. . .which, for better or worse, has become the famous sound and feel of a Harley.

Despite the odd engine design, Harleys became the heavyweight bike of choice for American motorcyclists, accounting for more than half of U.S. sales.

In the century since its founding, the company walks a tightrope between keeping its traditional outlaw biker market happy and also selling hogs to the rebel dentists, lawyers, and CPAs who make up a larte part of their customer base now.  Whether they can keep pleasing everybody without ending up pleasing nobody remains to be seen.  Still, the Harley mystique continues, even as their owners cheerfully complain about them.  For example:  “Harleys leak oil, the vibrate bad, and you can’t turn the things,” groused one biker to Forbes.  So why does he keep buying them? “You get laid.”