Two-Wheeled Duesenberg: 1926 Ace Four

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Henderson’s Four was not the first 4-cylinder motorcycle produced in the U.S., but it was the first to be successfully adapted to American conditions.
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1926 Ace Four
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1926 Ace Four
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The Ace was continually improved during its almost seven year existence. As a result, many parts are only correct for specific years.
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1926 Ace Four
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Owner Michael Terry enjoys riding his Ace. “The motor is very smooth. It’s like riding an airplane,” Michael says.
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The Ace inline four has a horizontally split aluminum crankcase, with the crankshaft mounted in three plain bearings.
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The Ace inline four has a horizontally split aluminum crankcase, with the crankshaft mounted in three plain bearings.
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As William Henderson slowly spun in his grave, the light, sporty Ace gained weight as Indian added in additional lower end rigidity and a stronger frame.
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There’s no rear suspension on the Ace, but the generously sprung saddle smooths out most of the bumps along the way.

1926 Ace Four
Claimed power: 16hp
Top speed: 75mph (est.)
Engine: 77ci (1,265cc) air-cooled intake over exhaust inline four, 2.75in x 3.25in bore and stroke
Weight (dry): 365lb (166kg)
Fuel capacity/MPG: 3.75gal (14.2ltr)

The 1920s was a period of optimism in America. There was a feeling that prosperity would never end, that any business could make a profit, and that anything that could be built could be sold. When a consortium revived the Ace motorcycle and started production in Detroit in 1925, they had no problem finding investors. Unfortunately, it wouldn’t last.

This Detroit-based group was the third company to produce the Ace, a creation of William Henderson, arguably one of the best motorcycle designers the U.S. has ever produced. Henderson was the son of a vice president of the Winton Motor Car Company, one of the first automobile manufacturers in the U.S. He studied engineering, and by 1910 was working for a gasoline engine company in Rochester, New York. William liked motorcycles, and in his spare time he turned to designing a bike powered by an inline four engine. Henderson’s father didn’t think much of motorcycles, but after Tom Henderson, William’s brother, became interested, Pop loaned the pair enough money to go into business. The fledgling Henderson company set up shop in Detroit and began selling Henderson Fours in the winter of 1912.

A new four

Henderson’s Four was not the first 4-cylinder motorcycle produced in the U.S., but it was the first to be successfully adapted to American conditions. Early motorcycles were powered by single-cylinder engines. The first 4-cylinder motorcycle engine, built by FN (Fabrique Nationale de Herstal) in Belgium, appeared in 1905. It was very smooth but low on power, displacing only 362cc. Percy Pierce, the son of a wealthy industrialist, saw an FN in Europe and convinced Pop Pierce (of Pierce-Arrow fame) to front the cash to produce a similar machine in the U.S. Like the FN, the Pierce motorcycle was down on power. It was also very expensive to produce, and the Pierce Cycle Company failed in 1913.

Henderson’s four was both more powerful and cheaper to build than the Pierce. It was also more user-friendly than many contemporary motorcycles. As a result, it sold well, especially after Carl Stevens Clancy rode one around the world in 1912. Despite this excellent start, the Henderson company ran into difficulties during World War I, and the Henderson brothers accepted a buyout offer from industrialist Ignaz Schwinn, who was then building Excelsior motorcycles as well as bicycles. Schwinn saw the Henderson as a premium entry into the police bike market — one of the largest contemporary markets for motorcycles. He wanted to revamp the Henderson into a heavy, stable and reliable cop bike. The story is that this move displeased William Henderson, who saw his baby as a light sport bike. There may also have been a personality clash. In any event, Henderson left Schwinn in 1919, and soon announced his new Ace.

New horizons

The quickness with which Henderson’s new project appeared after his exit from Schwinn caused comment. It is probable that Henderson worked out a deal with backer Max Sladkin before he handed his notice to Schwinn. Ads for the new Ace appeared in late 1919, and production started in early 1920.

Henderson, mindful of the gossip, was careful to make sure that nothing on the Ace would interchange with anything on the contemporary Henderson. The design of his new Ace inline four followed what was standard practice of the day, but with ingenious little touches that were William Henderson’s trademark.

The engine had a bore and stroke of 2.7 inches by 3.25 inches for a total capacity of 74.5 cubic inches. Instead of the current Henderson engine’s flathead design, the Ace featured an intake over exhaust cylinder head (also known as an “F” head); the huge valves were an inch and a half across. To eliminate the messy oil spray endemic to contemporary intake over exhaust designs, Henderson enclosed the intake valves. To lube the top end, the rider lifted a spring-loaded cover and used an oil can to squirt oil on the valve stems. The crankshaft was mounted in three plain bearings in a horizontally split aluminum crankcase. Lubrication was by splash, a gear-driven oil pump at the front of the engine keeping the oil trough for the crank full.

The automotive-style, 3-speed handshift transmission was in unit with the engine and worked through a large multiplate wet clutch. A leading-link front fork with a compression spring carried inside a tube smoothed out the front end. There was no rear springing, but the ride was softened by generous seat springs.

Finished in a lovely shade of dark blue with cream wheels, the Ace had a polished aluminum exhaust and nickel-plated handlebars. A sculpted front fender led the eye over the slender gas tank to the rear wheel, and in between was the inline four, industrial art at its finest. The Ace weighed in at 365 pounds dry, although some sources say it was closer to 400 pounds.


The Ace was continually improved during its almost seven year existence. As a result, many parts are only correct for specific years. One of the first changes was a cylinder bore increase to 2.75 inches, giving a total capacity of 77 cubic inches, and a new inlet manifold and piston design debuted in 1922. At this point, disaster struck. William Henderson was out testing the new Sporting Solo when he was hit by an automobile and killed. Yet despite the death of its designer, the Sporting Solo, with high fin cylinders, new aluminum pistons, redesigned tappets and a new oil breather, came out in January 1923.

Following William Henderson’s death, Arthur Lemon, who had succeeded Henderson as chief engineer at Excelsior-Henderson, came over from Henderson to take over Ace’s engineering duties. But another problem was looming over Ace; an accounting error meant management had set the price for each bike at $335, less than cost, and the company was losing money on each sale. By the time the accounting department figured this out, Ace was solidly in the red.

In an effort to get the struggling Ace factory back on its feet, Arthur Lemon designed two racers, the XP-3 and the XP-4. The XP-3 was a 320-pound hill climber, which, with racer and test rider Red Wolverton in the saddle, won numerous events. The XP-4 was a one-off custom, designed from the ground up. Magnesium cases, “Swiss cheese” pistons (so-named from being heavily drilled for lightness), special thin-walled frame tubing and a one-off aluminum carburetor added up to a 45 horsepower bike that weighed 285 pounds. On November 19, 1923, Red Wolverton rode the XP-4 to a one-way record of 129.61mph.

Despite the engineers’ best efforts, Ace simply ran out of money. Production at the original factory in Philadelphia came to a halt in late 1924. The pieces were bought by a group of investors, who produced a few hundred bikes in Blossburg, Pennsylvania, before they realized that motorcycle production was not the piece of cake they thought it would be. This first group of investors handed over production to a second group of investors, incorporated under the name of Michigan Motors, who moved the factory to Detroit.

Before the Blossburg group sold the company, it produced an 8-page brochure extolling the merits of the Ace to weekend warriors. At a time when most people worked 10 hours a day, six days a week, the Blossburg group suggested that the Ace could take a rider to “the country club, golf links, tennis court, baseball diamond or swimming pool for a few hours recreation in the afternoon.” The brochure went on to state, “The Ace is so economical to operate that expense of any trip becomes negligible” — low enough, one assumes, to get around even if all your money was spent on that country club membership.

The one major update to the Ace engine in the Blossburg/ Michigan Motors era was a change to a one-piece intake manifold and a four-cage intake valve assembly. The carb was now a Schebler DLX25. The Blossburg plant painted its bikes Ace Blue, while the Michigan Motors factory went for a light green scheme.

White Ace

The Michigan Motors group didn’t last long, with production coming to a standstill in late 1926. Looking to expand its product line, the Indian Motocycle Company bought the rights to Ace in the spring of 1927 and moved production to its Springfield, Massachusetts, factory. As William Henderson slowly spun in his grave, the light, sporty Ace gained weight as Indian added in additional lower end rigidity and a stronger frame. Indian, like Schwinn before it, was going after the police market, and to get that market they believed they needed to beef up the Ace accordingly. The Ace became the Indian Ace, and then by mid-1928 the Indian Four. Indian built the Four until 1942.

American inline fours were some of the first classics to become collectible, and one of the earliest collectors was Milby Jones, one of the founding members of the Antique Motorcycle Club of America. When Michael Terry met him, he had 50 or 60 motorcycles in his basement. “He never sold anything,” Terry remembers. Jones was also interested in cars. The two were talking one day when Jones mentioned he had sold a Plymouth Barracuda. Selling anything was totally out of character for Jones, and Terry mentioned this. Jones’ response was even more of a surprise. “What do you like?” he asked. “I might sell it to you.” As it turned out, Terry had been admiring a red Ace, one of two Jones owned.

That was about 25 years ago. The Ace Terry bought from Jones was all there, but the paint was the wrong color and put on with a brush. The engine was in rough shape, the electrical components needed work and the brakes did not function. At least one white Ace was built by either Michigan Motors or Blossburg, and when Terry located a contemporary photo of this machine, he decided to duplicate it.

Master machinist Erv Truax did the engine, one of several he has built for Terry, who is very pleased with the results. “I don’t do much maintenance. Once Erv set it up, it has always run.” Terry, who was in the auto body business for 30 years, tackled the rest of the Ace. He lined the brakes with Green Gripper brake lining. “It likes the cast iron drums,” Terry says. Next he got the electrics operational, and then bolted the engine into the frame. “I got a couple of friends to help lift the engine in,” he adds.

This Ace runs on a regular basis, and Terry once rode it touring around Florida. It uses regular gasoline, with a little Marvel Mystery Oil added for top-end lube, and it starts easily. “These bikes will start if they have fresh gas, fresh oil, a hot magneto and a good carburetor that is working properly with good floats,” Terry says. “The clutch will stick if it hasn’t been run recently. Cruising speed is 62-65mph — you can travel at that speed for some time without hurting the motor. I have had it up to 70mph.”

The tires are clinchers, an early type of tire that must be kept properly inflated to stay on the rims. But even so, Terry says the Ace is “beautiful on curves if you run the right pressure. The bike handles beautifully. You have to pay attention, though. The Ace doesn’t really stop, even with the good brake linings.” The best part of the Ace is, not surprisingly, its engine. “The motor is very smooth,” Terry says. “It’s like riding an airplane. It also has this great sound. It gets into this hum, and if you throttle up the hum just gets louder.”

Terry also owns a few Hendersons, the Ace’s progenitor, but says they don’t compare. “They are like riding a truck compared with the Ace,” Terry says. “An Ace is the Duesenberg of motorcycles. You can’t get bikes like this anymore.” MC

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