A Stunning Icon of American Motorcycle Muscle

The spectacular 1923 Ace Four Sporting Solo was the ultimate American 4-cylinder motorcycle in its day. Its reputation was second to none, and for a time was the fastest production motorcycle in the world upon introduction. The Ace was the final legacy of William Henderson, who had already established his machines’ reputations as the among toughest and fastest motorcycles on earth. William and Thomas Henderson founded the Henderson Motorcycle Company in Detroit in 1912, and the brothers immediately established an amazing reputation for their machines as durable, fast and beautifully built—the “Duesenberg of Motorcycles” they were often referred to as.

In the economic turbulence of the First World War, when inflation made the purchase of even raw materials difficult and increasingly expensive, the Hendersons sold their company to Ignaz Schwinn in November 1917. Schwinn was looking to expand his range of Excelsior single- and twin-cylinder motorcycles, and purchasing Henderson was a smart shortcut to a premium 4-cylinder range leader. The buyout contract for the Henderson brothers stipulated a salary and jobs for both brothers under Schwinn, but it didn’t take long for both to pack up and leave. Thomas Henderson traveled to Europe, while William left Schwinn with an idea for a new 4-cylinder motorcycle by early 1920. Henderson secured financing for his new project and purchased the old Savage Arms building in Philadelphia; it only took a few months of tooling and casting before the experienced 4-cylinder bike builder introduced his new and spectacular Ace Four.

The Ace was considerably modernized compared to the last of the “original” Hendersons. It retained F-head cylinders and a displacement of 75 CI (1220cc), with splash lubrication and a bolted-on 3-speed gearbox. The engine made 20 hp, and the crankcase was stronger than the Henderson with thicker bearings and a heavier flywheel. The two intake blocks sat atop four separate cast-iron cylinders, with large valves and a well-ported inlet tract for better power. The 59-inch wheelbase was two inches longer than the final “short” Henderson 4, and the weight was kept down to 365 pounds. The Ace was strikingly beautiful in Packard Blue and highlighted with cream painted rims. Its lines were beautifully compact and modern, and gave an impression of speed even at a standstill. It certainly appealed to the sporting rider of the time, who wanted a smooth and fast motorbike. Wisely, no parts were interchangeable between the Ace and Henderson 4s, so no patents were infringed.

Tragically on December 11, 1922, shortly after 11a.m., William Henderson was struck by an automobile while testing his new Ace Sporting Solo in Philadelphia. He died at the age of 39 in Frankford Hospital without regaining consciousness. Arthur O. Lemon, former salesman for Henderson and current head of Excelsior and Henderson Engineering at Excelsior Motor Manufacturing & Supply, left Excelsior in 1923 to replace Henderson as Chief Engineer at Ace.

This particular 1923 Ace Four Sporting Solo was originally sold to Kjell David Anderson in Norway, and was later exported to Sweden. Well known Swedish collector and restorer Leif Jönson restored this Ace before the MC Collection purchased it in 2007. It has been tested and ridden by Lasse Olsson of the MC Collection, and was restored to full road worthiness. A running, rolling, important piece of American motorcycle history. Currently on display at the Throttlestop Museum in Elkhart Lake, Wisconsin, this legendary motorcycle is even more striking in person than in photos.

For this and all their beautiful examples from motorcycling history, visit the Throttlestop Museum for yourself, or take the virtual tour via the link below. You’ll give them your email, to which they will send an entrance code, and you’re in:

Throttlestop Museum

*Source material provided by Mecum Auctions and Throttlestop. Photos by Throttlestop.

Let’s all admit: That is one beautiful motorcycle. Tell us what you think in the comments below!


  1. August Mendieta

    Gorgeous motorcycle. Would love to have owned one. Would still like to own one.

    • Rob Brooks

      Absolutely agree. A true dream bike, touchstone of moto history.

  2. Brian SCHARFF

    The ThrottleStop is a Must-See. Great People.

    • Rob Brooks

      It certainly is. An incredible collection.


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