FN Four

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FN Four
FN 363 cc viercilinder 1905.jpg
1905 FN Four
Manufacturer Fabrique Nationale
Production 1905–1923
Engine 350-750 cc (max) inlet-over-exhaust with compression release
Bore / stroke 45 mm x 57 mm[1][2]
Power 5 hp (3.7 kW) (498 cc version)[3]
Ignition type Magneto
Transmission Shaft drive
Frame type Steel duplex cradle
Suspension Front: Bottom-link fork
Rear: Rigid
Fuel capacity 1.5 US gal (5.7 l; 1.2 imp gal)

The FN Four was the world's first production inline-4 motorcycle, manufactured in Liége[4] by Fabrique Nationale from 1905 until 1923.[5][6] It was also, at 40 miles per hour (64 km/h), the world's fastest production motorcycle from 1911 until 1912.[7][8]

The motorcycle was developed in 1904, tested late that year, and had its public debut at the 1905 Paris Motorcycle Show.[9] It was a commercial success upon release, with production increasing over its twenty-year run.[10][11]

Technical details[edit]

The motorcycle was originally single-speed. In 1909, a two-speed transmission was offered,[12] then three-speed in 1914 with the 748 cc engine.[13] It had a single speed shaft drive turned by a bevel gear.[10] The rider started the engine by pedaling bicycle style pedals with a chain drive and sprockets to the rear wheels.[13] The 1905 model had a high-tension Bosch magneto ignition,[14]:43 a spray carburetor, and a rear coaster brake operated by the pedals.[10] It had a 5:1 reduction ratio to 26" wheels.[14]

By 1908, it had a two speed transmission with a plate clutch, overcoming the speed limitations of the earlier model.[10] In 1909 a rear drum brake was fitted.[13] In 1910 engine was redesigned and enlarged to 498 cc (30.4 cu in), the carburetor was moved and a new oiling system was used.[13] The weight in 1910 was 165 lb (75 kg).[7]

For the US market, the 1908 model was upgraded and released as a 1908​12 model, called the F.N. Big Four.[15] Engine power was raised from 4 12 hp (3.4 kW) to 5 hp (3.7 kW), the frame size was reduced from 22 to 20 inches (560 to 510 mm) allowing the rider to sit with both feet on the ground, the wheel rims were made heavier and would fit American tire sizes, and it came with tires with a heavier tread.[15]

The 1911 model weighed 185 lb (84 kg) and had a wheelbase of 56 in (1,400 mm).[14]:43 The US model had either Goodrich or another imported brand of tires, and a leather seat made by the Mesinger Bicycle Saddle Company of New York.[14]:43 By 1911 bore × stroke was up to 2 116 in × 2 116 in (52 mm × 52 mm) and nominal output was up to 6 hp (4.5 kW).[14]:20

The motorcycle had bicycle-style pedals used for starting until 1913 when a kickstarter was adopted.[13]

Four cylinder engine[edit]

FN Intake-over-exhaust four cylinder motor c. 1911
Sectional elevation of engine.
End section showing inlet over exhaust valves and atmospheric intake.

The FN Four's engine was designed by Paul Kelecom who had designed single cylinder engines prior to the FN.[16] The air cooled longitudinal layout was prone to overheating the rear cylinders, a trait overcome in later designs with water cooling and transverse layout.[17]

FN originally fitted the Four with a 350 cc[16] or 362 cc[13] engine. The displacement increased over time, to 410 cc in 1906,[18] later to 498 cc for the US market, and a 748 cc variant was produced in 1914. The engine had to be periodically oiled during riding, with hand pump.[16] The intake valves were atmospheric, pushed open by ambient air pressure against light springs during the piston's intake stroke,[16] up to the 1914 748 cc model, which replaced the automatic inlet valves with mechanically actuated side valves.[13]

First four cylinder motorcycle?[edit]

The FN Four was the first production inline-four, but not the first motorcycle with a four-cylinder engine. It was preceded by a boxer 4 manufactured in 1897 by Henry Capel Lofft Holden,[19][20] and an obscure air-cooled inline-four developed in 1903 by C. Binks of Nottingham, England, but never produced commercially.[11][20] A longitudinally mounted four-cylinder "model CCCC" prototype was created by Laurin & Klement and shown in Paris in 1904 but it was essentially four ganged single-cylinder engines with four separate crankshafts, not an inline-four in the modern sense.[21][22][23][24] The FN, at the time of its introduction, was the only four-cylinder motorcycle for sale in America.[25] (later Henderson Motorcycle sold a four from 1912 until 1931.)

Comparable motorcycles[edit]


Model year Model name Displacement Power Transmission Brakes Wheelbase Dry weight
1905 FN Four 362 cc (22.1 cu in)[26] 3.45 hp (2.57 kW) @ 1800 rpm 1-speed w/pedal start Rear rim and coaster 165 lb (75 kg)
1906 412 cc (25.1 cu in) 4 12 hp (3.4 kW) 1-speed w/pedal start Rear rim and coaster
1908​12 Big Four 5 hp (3.7 kW) 1- or 2-speed w/pedal start Rear rim and coaster
1909 6 hp (4.5 kW) 1- or 2-speed w/pedal start Rear: drum
1910 498 cc (30.4 cu in) 1- or 2-speed w/pedal start Rear: drum 165 lb (75 kg)
1911 6 hp (4.5 kW) 2-speed w/pedal start Rear: drum 56 in (1,400 mm) 185 lb (84 kg)
1913 2-speed w/kickstart Rear: drum
1914–1923 700 748 cc (45.6 cu in) 3-speed Rear: drum


The success of the FN Four directly led the US Pierce Four to use the same engine mounted longitudinally with a shaft drive.[5] Pierce-Arrow's Percy Pierce brought a 1908 FN Four home from Europe to disassemble and study.[5][27] Indian, Henderson and Cleveland fours were all said to have been inspired by the FN Four.[28]

Early examples of the machine are rare; a 1904/1905 model, reported to be the earliest known example, sold at a record price in a 2006 auction for over US$100,000.[29]

Race history[edit]

A FN Four took third place in the 1908 Isle of Man TT,[30] and was the first four-cylinder engine vehicle entered at the Isle of Man TT.[9] In 1908 another FN Four took the gold medal in a Motor Cycling Club endurance race on the 1,400-kilometre (870 mi) London–Edinburgh–London course.[31]

Museum exhibits[edit]

An FN Four was exhibited at the Guggenheim Museum's The Art of the Motorcycle exhibition in New York and Las Vegas. Models are in the permanent collections of Petersen Automotive Museum in Los Angeles,[32] Seal Cove Auto Museum in Seal Cove, Maine,[33] the Musée de la moto et du vélo in Amnéville France,[34] and others.

See also[edit]


  1. ^ Walker (2000, p. 32)
  2. ^ Cycle and Automobile Trade Journal 1906, p. 206: 44×67 mm, displacement was computed 410 cc (1906 engine)
  3. ^ Duckworth 2012, p. 27
  4. ^ Motor Age 1916, p. 27
  5. ^ a b c Edwards 1997, p. 43
  6. ^ Petersen Automotive Museum: "The 1904/05 FN was the world's first mass produced four-cylinder motorcycle."
  7. ^ a b Brown 2006, pp. 12–13
  8. ^ Krens 2001
  9. ^ a b d'Orléans 2008
  10. ^ a b c d C. F. Caunter 1955, p. 21
  11. ^ a b Hough and Setright 1996, p. 38
  12. ^ Offered in 1909 in the United States, see Cycle and Automobile Trade Journal 1909, p. 188
  13. ^ a b c d e f g Duckworth 2012, p. 26
  14. ^ a b c d e Motorcycle Illustrated January 12, 1911
  15. ^ a b The Horseless Age. 1908.
  16. ^ a b c d Kevin Cameron at Krens 1998, p. 109
  17. ^ Cameron 2012
  18. ^ Mitchell 1998
  19. ^ Walker 2006, p. 28
  20. ^ a b Hodgdon 1976, p. 26
  21. ^ d'Orléans 2013
  22. ^ Malanik 2008
  23. ^ Kirchberger and Ludewig 2007, p. 39 states "Die L&K Viercylinder-maschine CCCC war von 1904 bis 1909 in angebot" (in production from 1904 until 1909).
  24. ^ Walker 2006, p. 28 states that production did not start until 1905
  25. ^ Hodgdon 1976, p. 20
  26. ^ Walker (2000, p. 32) displacement was computed 362 cc (1905 engine)
  27. ^ de Cet (2002, p. 360) states that Pierce "did not copy" the FN Four but "its influence...was apparent".
  28. ^ de Cet 2002, p. 159
  29. ^ Roadracing World 2006
  30. ^ IOM Times 1908
  31. ^ Walker 2000, p. 32
  32. ^ Petersen
  33. ^ 1912 Fabrique National Motorcycle, Seal Cove, Maine: Seal Cove Auto Museum, retrieved 2013-10-20 
  34. ^ Ralf Kruger (September 26, 2011), "A visit to the Motorcycle and Bicycle Museum Amneville", Ed Youngblood's Motohistory, Ed Youngblood, retrieved 2013-10-20 


Further reading[edit]

External links[edit]

Preceded by
Werner New Werner
Fastest production motorcycle
Succeeded by
Scott two speed