American Iron Magazine Presents 1001 Harley-Davidson Facts. Tyler Greenblatt
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the oil tank was still used for excessive uphill or sidecar loads. This system was in place until 1937, when all Flatheads were converted to recirculating oil.
188 Sure, Harleys are a great way to travel, but some times even the narrowest of motorcycles can’t sneak through a traffic jam. So why don’t you take to the air? In 1927, a do-it-yourself kit available through Popular Mechanics included an adapter that mounted to the primary sprocket shaft of a JD engine to which a builder then attached an airplane propeller and used that setup to power a homemade aircraft.
189 Another interesting propeller-driven variant is the ice glider kit available through the Mead Glider company. Unlike the aircraft propeller, the Mead kit ran a chain off the stock primary sprocket to turn the propeller, which was placed on the ice glider’s chassis toward the top of the cylinder heads. The company advertised its kit to Harley-Davidson owners with the recommendation that they could build the ice glider easily. Then, during the winter, transfer their motorcycle engine into it.
190 When initially purchasing a motorcycle in the 1910s, it was important to mention whether or not it was for sidecar use. H-Ds meant for solo use arrived from the factory with a 15-tooth engine sprocket, which was well matched for the weight and acceleration versus top-speed needs. A sidecar rig with that gearing accelerated at a much slower rate while also putting too much pressure on the clutch, especially on hills. In addition, the added weight and running gear couldn’t propel the machine to top speeds. Therefore, a 14-tooth engine sprocket was offered for sidecar customers so they could get the most out of the heavier machine.
191 In 1924, Harley-Davidson hired Ace’s chief engineer, Everett DeLong, on a six-month contract to develop a 4-cylinder engine for The Motor Company. Ace had been successful with this type of engine for many years. Initially, he worked one of his inline-4 Ace designs into a JD chassis, but the production version would have required too much expensive tooling at the factory. His next prototype engine wouldn’t have added much to the budget. He mounted two JD V-twins side by side, connected at the crankcase. The displacement of both engines would have to be reduced to end up with an 80-ci total displacement, but this design created no new cooling issues and required little factory tooling. In the end, Harley-Davidson vetoed the project, not wanting to diversify with risky models that might tarnish the brand.
192 Harley-Davidson solved a serious lubrication problem with the JD valvetrain in 1924 when it began fitting Alemite grease fittings into the heads. Using a standard grease gun, a bike’s owner could easily lubricate all of the valvetrain bearings in the heads, greatly reducing noise and heat. In addition, the chassis included ten other Alemite grease fittings. New JDs were actually sold with a grease gun and a can of grease.
193 Harley-Davidson’s first automatic oil pumps were built right into the cam cover on 1915–1919 H-Ds; they contained a sight glass so that the operator could ensure that oil was moving through the system. As bikes got faster and more complicated, it became unreasonable to ask the operator to continuously pump oil into the crankcase by hand. That’s why these automatic systems evolved. However, the hand-pump was standard equipment until 1937, just in case the engine was under more stress than the oil pump could cover.
194 Today’s big–cubic-inch Harleys and many heavily modified V-twins use compression releases mounted to the cylinder heads. They reduce compression when starting the engine for less strain on the starter motor. In 1916, when “step-starters” were introduced, they employed a similar, yet slightly more complex system for easy starts. A series of intricate linkages went from the kicker to the engine’s exhaust valves that, upon kickstarting the bike, lifted the valves and reduced compression for less resistance.
195 Have you ever looked at an old H-D engine and wondered why all of the metal fuel and oil lines are coiled? The coils were used because the lines come from a solid point on the bike (such as the gas tank and oil tank) and go to a moving, vibrating part of the bike (the engine). If the metal lines went from Point A straight to Point B, they’d crack and break very quickly because of the stress. By putting a coil in the line, they can shake, rattle, and roll all they want without snapping because of the flex that is built in.
196 Although earlier Harley engines had the intake pocket valve mounted directly on top of the cylinder, later engines used a true Intake Over Exhaust (IOE) design by positioning both valves on the side of the cylinder, which creates a wider combustion chamber. Not only did the later valve design allow easier maintenance and adjustment on the intake valve, but it also allowed the engineers to use a shorter rocker arm, which was more dependable and easier to articulate.
197 In 1927, Harley-Davidson introduced its first “wasted spark” ignition system: A circuit breaker and a single ignition coil fired both spark plugs at the same time. In one cylinder, the air/fuel mixture was ignited, while the spark had no effect in the other cylinder. This system allowed the removal of the distributor and the second coil. In 1929, Flathead twins and IOE twins shared the same ignition spark coil.
198 In 1926, Harley-Davidson offered an exhaust cutout system that, for the first time, deflected gases away from the rider when it was open. The 1926 exhaust system uses a rear-facing deflector, which is positioned directly over the muffler’s cutout exit to force exhaust gasses rearward. An otherwise identical exhaust system was actually used in 1925; when the cutout was open, a simple hole in the side of the muffler allowed hot exhaust gases to exit in every direction, including up toward the rider. Because 1925 and 1926 models are otherwise identical, taking a peek at the exhaust system is a good way to identify the year without getting down on your hands and knees to read the engine number.
199 The legendary Two-Cam street engines of 1928 and 1929 received a significant dose of detuning compared to the factory racers from which they were derived. However, some unique go-fast parts made it through to production. The most unique aspect of the Two-Cam compared to the standard single cams was the use of a direct valve gear system to operate the valves. Tappets, rather than roller arms, guided the cam lobes, which, in addition to stronger intake valvesprings, allowed the Two-Cam to rev higher and reach higher power numbers more reliably.
200 In 1924, The Motor Company introduced its line of aluminum-alloy-piston motorcycles with the E series. This series included the JE solo, JES sidecar, as well as the JDCA solo, and JDSCA sidecar. A Harley-Davidson advertisement in the October 1923 edition of Popular Mechanics gives insight into the practical use of aluminum-alloy pistons. The ad claims that aluminum-alloy pistons allow the rider to “hit up any speed and hold it, all day long if you want to, and the 1924 Harley-Davidson won’t overheat.” The ad also claims that the lightweight pistons “cut vibration in half” and are “far more durable.”
201 Effie Hotchkiss and her mother, Avis, cemented their names into history in 1915 by becoming the first women to ride from coast to coast on a motorcycle. They traveled from their home izn Brooklyn, New York, to San Francisco, California, on a 1915 Harley-Davidson with a sidecar. The journey took two months to complete, and served as an inspiration to women motorcyclists then, as it still does today! Effie and Avis added to their legend by carrying a small bottle filled with water from the Atlantic Ocean. When they arrived at the Golden Gate Park beach, they emptied the bottle into the Pacific.
202 A 1926 Peashooter was featured on the September 5, 2013, episode of Velocity’s “What’s In The Barn.” Dale and Matt Walksler of Wheels Through Time museum uncovered one of these bikes in an old military surplus warehouse near the museum in North Carolina.
203 In 1918, Seattle dealer Harry Trainor gave Vaudeville star Trixie Friganza a ride in a 61-ci JD with sidecar. A famously portly woman, the press covered the ride around hilly Seattle, and portrayed the Harley-Davidson as a powerful and durable machine.
204 According to a 1929 Harley-Davidson advertisement, “Now comes the quiet motorcycle! Noise has gone out of fashion. The public has been demanding a more and more quiet-functioning mechanism.” While that part about the public demands might be true today, “smooth, quiet, purring power” is not particularly fashionable today, even though it was apparently a hot selling feature in 1929.
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