Between 1910 and 1914 Royal Enfield used different Motosacoche v-twin engines in there lightweight motorcycle types 150, 160 and 170.
Motosacoche was founded in 1899 by Henri and Armand Dufaux in Geneva, Switzerland. Motosacoche was once the biggest Swiss motorcycle manufacturer, known also for its proprietary-engines used by other European motorcycle manufacturers.
From 1900 Motosacoche produced a bicycle auxiliary engine in a subframe that could be 'hung' into a conventional bicycle like an engine in a bag, hence the Motosacoche name, meaning "handbag engine". See the pictures of the 1902 and 1908 version of this clip-on engine.
In 1905 the firm was given the legal structure of a "Societe Anonyme" based at Rue Acacias, Geneva. The Dufaux brothers soon left the company and concentrated on other things, like building airplanes.
Gradually the engines became bigger and more powerful, twin cylinders were produced and the initial idea of a motorized pedal-bike was given up. The factory built complete motorbikes under the "Motosacoche" label, but kept on selling M.A.G. (Motosacoche-Acacias-Geneve)-engines to many well known manufacturers in France, England, Germany, Austria and Italy. In France and Italy there were even factories producing Motosacoche motorcycles under licence.
In 1910 Royal Enfield started with a 297cc 2¼hp Motosacoche v-twin and a year later they used the Motosacoche 344cc 2¾hp engine in a successful V-twin model. They are reputed to have supplied Triumph, Ariel, Matchless and Brough-Superior with engines at times too, first through H & A Dufaux England Ltd, and then, by 1912, Motosacoche Ltd (GB), with Osborne Louis De Lissa. Motosacoche had factories in Switzerland, France and Italy, and supplied M.A.G. engines to other continental manufacturers including Clement, Condor, Imperia, Neander and Monet Goyon.
See the pictures of the 1912 Motosacoche 2C5 quality machine with bore x stroke of 54 x 75 mm which features an Enfield two speed gear system and all chain drive. Note the support bracket for the starter handle on the right side footboard. All cycle components for the Motosacoche motorcycle were made by the Enfield Cycle co. ltd., like they were for the Clement (see seperate chapter) and Gladiator with Motosacoche engines.
In the early twenties the Motosacoche range was equipped with engines in capacities of 500, 600 and 1000 cc. The 592 cc 2C12 engine in the pictures below has bore and stroke dimensions of 64×92 mm and delivers its power at a leisure 2400 rpm.
Note the luxurious specifications of this splendid touring motorcycle: hand crank starting, sprung seat pillar, large footboards, three speed gearbox with tank top control and fully enclosed rear chain.

Success in numberless racing events helped to create a solid reputation on the tracks. M.A.G. engines played an important part in Europe's motorcycling-scene, often compared with big names as J.A.P.! In 1913/14 the Matchless ohv-works-racers (more successful at Brooklands than at the T.T.) were equipped with M.A.G. engines, as well as the French G.P. winning Clement-Gladiator and Motosacoche.
When the Bol d'Or 24-hour event was first held on the outskirts of Paris in 1922 the winning rider covered more than 750 miles (1206 kilometres) on a 500cc Motosacoche.
In the 1928 European championship the Marchant-designed o.h.c. works-racers were ridden to victory by Walter Handley in the 350 AND the 500 cc events!
Bert le Vack joined Motosacoche in the late 1920s after he worked for JAP and the London Depot of the Hendee Manufacturing Co. (Indian). He had ridden in the 1914 Isle of Man Tourist Trophy and became the works rider, chief designer and tuner. Le Vack was killed in an accident in the Swiss Alps on 17 September 1931, while testing the 'Flying Banana' Motosacoche A50 on public roads close to their factory.
But most of Motosacoche's excellent reputation was based on motorcycles for everyday-use. From the twenties until WW2 many 250, 350 and 500 singles (mostly of IOE and OHV layout) and V-twins from 500 to 1000 cc (most of them with IOE, the 850 had SV) provided long and loyal service to their proud owners.
During the 1930s Motosacoche were eclipsed by the Norton Motorcycle Company and went into decline.
During WW2 many M.A.G.-engined motorcycles and side-cars (usually with Motosacoche and Condor labels) helped the Swiss army to protect the small country from the menacing conflict around them.
After World War II, an unusual Marchant designed 200cc SV was shown at the 1947 Geneva motor-show, it came to late though, remained a prototype and never got produced. In 1953 Richard Kuchen designed German UT motorcycles were marketed under the Motosacoche name, but this was to late and not successful, and by 1956 motorcycles were no longer manufactured, but MAG stationary and industrial motors continued.
A number of pictures are from the Dutch dealer of Antique Motorcycles Yesterdays.