FN Four: The First Production Four-Cylinder Motorcycle
The FN Four, produced by Fabrique Nationale (FN) in Belgium, is widely recognized as the world's first production four-cylinder motorcycle. With its innovative design and advanced engineering, the FN Four redefined the motorcycle industry. Manufactured between 1901 and 1957, it was a major milestone that influenced future generations of motorcycles. Naked Racer Moto Co is currently restoring one of the 1905 FN Four motorcycles, a testament to the lasting legacy of FN's groundbreaking engineering.
The First 4-Cylinder Motorcycle (Not in Production)
In 1897, Henry Capel Lofft Holden built one of the earliest examples of a 4-cylinder motorcycle. Unlike the FN Four, which became a production model, Holden's horizontal 4-cylinder direct drive motor bicycle was a one-off design and was not mass-produced. It played a significant role in early motorcycling history, contributing to the development of four-cylinder engines for motorcycles.
The engine features four horizontal, air-cooled cylinders with a 2.125-inch diameter and a 4.5-inch stroke, placed two in line on each side, incorporated directly into the frame. The pistons are linked to parallel overhung cranks on the rear driving axle, which created an impulse at every stroke, producing a unique drive experience.
This motorbike also had a carburetor of the surface type and a battery ignition system. The engine produced about 3 horsepower at 430 RPM, enabling a maximum speed of 20 miles per hour. The total weight of the machine was 123 lbs.
Though Holden's motor bicycle wasn't commercially successful or mass-produced, its innovative use of a four-cylinder engine paved the way for future developments in motorcycle engineering, especially in the high-performance and racing sectors.
FN's Evolution from Firearms to Motorcycles
Fabrique Nationale (FN), established in 1889, initially focused on firearms manufacturing. However, by 1901, FN diversified into bicycles and motorcycles, marking the beginning of their significant impact on the motorcycle industry. The company became well-known for its shaft drive technology, a revolutionary feature that FN utilized from 1903 to 1923, setting it apart from competitors at the time.
Paul Kelecom’s Role in the Creation of the FN Four
The FN Four was the result of the work of FN's chief engineer, Paul Kelecom, who was responsible for the motorcycle's design and technological advancements. At the time, most motorcycles used single-cylinder engines, which caused severe vibration, affecting their overall performance. Kelecom's solution was to introduce a four-cylinder engine, which allowed the inner pistons to cancel out the vibrations from the outer pistons, resulting in a smoother ride.
Innovative Design: The FN Four’s Key Features
The FN Four introduced several key features that made it stand out in the early 20th century. Unlike conventional motorcycles, the FN Four's engine was mounted between split-bottom-frame rails. This design allowed for better weight distribution and more stability. The motorcycle also featured a bevel-driven, ball-bearing-supported driveshaft, which improved durability and performance compared to the belt-driven systems that were common at the time.
The FN Four was powered by a 350cc four-cylinder engine, utilizing atmospheric intake valves. Although the engine offered smoother operation, the lack of a multi-speed gearbox limited its speed range. Despite this limitation, the FN Four became known for its superior handling and performance, especially in endurance races and long-distance events.
Racing Success and Public Reception
Upon its release, the FN Four immediately impacted the 1905 Paris Motorcycle Show, drawing attention for its advanced technology and innovative design. The FN Four’s success in racing further cemented its place in motorcycling history. Famous riders such as S. "Ginger" Wood competed on FN motorcycles, helping to establish the brand as a leader in performance.
However, despite its success in races, the FN Four’s production cost was relatively high due to the sophisticated design, including the four-cylinder engine and shaft drive. This high manufacturing cost made it more expensive than competing motorcycles, limiting its commercial appeal. FN responded by increasing the engine displacement to 493cc for the European market and 498cc for the American market, adding a two-speed gearbox and an automotive-style clutch to make the bike more accessible to a broader audience.
Transition to Chain Drive and the End of Production
By 1926, after Paul Kelecom's departure, FN began phasing out the FN Four, replacing it with more affordable chain-driven singles and twins. These motorcycles were cheaper to produce, and the transition marked a shift in the market’s demands. While the FN Four was a significant innovation in motorcycle design, it was not as commercially viable due to its high production costs and limited speed range.
As the motorcycle industry evolved, FN refocused its efforts on producing motorcycles with more conventional designs, such as side-valve (SV) and overhead-valve (OHV) models. The company continued to innovate in the motorcycle space, producing a range of motorcycles with unit-design engines. However, by the mid-1950s, FN withdrew from the motorcycle market and transitioned into automobile production, marking the end of an era.
The FN Four's Legacy in Motorcycle Engineering
Even though the FN Four was discontinued in the late 1920s, its legacy lived on. The four-cylinder engine design became a hallmark of high-performance motorcycles and influenced future manufacturers, such as BMW, which adopted similar engineering principles in its motorcycles. FN’s use of the shaft drive system also became an enduring feature in high-end motorcycles, particularly in the racing sector.
Today, the FN Four is considered a collector's item, admired by enthusiasts and preserved in museums around the world. Its impact on modern motorcycle design is still felt today, and the FN Four remains a symbol of FN's engineering excellence and forward-thinking approach to motorcycle manufacturing.
The FN Four is more than just the first production four-cylinder motorcycle; it represents a turning point in motorcycle design and performance. The innovative engineering behind its four-cylinder engine and shaft drive system laid the groundwork for the motorcycles that followed. Though its commercial success was limited, the FN Four’s technical achievements have ensured its place as a foundational piece in the history of motorcycling.
References: The New Illustrated Encyclopedia of Motorcycles (2004) and The Art of the Motorcycle at the Guggenheim Museum.
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