Léon Demeester achieved considerable success on the racetracks, and in 1905 joined Dominique Lamberjack to form Demeester & Lamberjack in Courbevoie.
The company built automobiles, and before the first war became Sinpar. That company was still going in the late 40's early 50s, with Demeester still heavily involved in racing - but on four wheels.
Bourdiaux twin-cylinder engines were used in some of the Demeester racing motorcycles.
December 1901 Paris Salon
§ 5. - Demester Bicyclette. (1)
The Demester petrol bicycle can, it is said, make 70 km/h; it has a 3 horsepower, two-cylinder engine placed vertically on the underside of the frame, between the crankset and the rear wheel. The transmission of the movement to the latter is by chains and toothed wheels. It weighs 48 kg, of which the engine counts for 18 kg.
Denis Blaizot in Gloubik Science
Denis Blaizot in Gloubik Science
A night in June, clear and moonlit From the Arc de Triomphe to the gates of the Bois de Boulogne, the Avenue de la Grande Armee, "Wheel street," as "Mr Dooley" called it when he was in Paris, is in a hum of excitement and of expectation.
The racers are dressed in oilskins, with close-fitting skull caps, and as the pistol cracks all run their pedalless steeds along, working up speed, and as soon as maybe leap on to the saddle.Then pandemonium reigns. Each motocyclette makes as much noise as a Maxim, and the exploding petroleum flashes steely blue between each rider's legs, and looks like lightning. Bang! Bang! Bang! goes the petroleum, and as the pace works up the thunder of the motocyclettes on the wooden track adds a low rumble of its own, so that an onlooker could close his eyes and imagine himself listening to a battle on the veldt. The noise may be imagined when I say that the enormous crowd was practically shouting its hardest during the whole race, and that the only voices I could hear at all. were those of people immediately around me. As for the pace, nothing that I can say will convey the least nation of it, except the simple figures. Watching those banging, fire flashing things rush round and round, covering the 330 yards in less than ten seconds even before they were at their top speed, made it impossible to fancy that.'there were men on them. As they passed under us, however, the men were visible; sitting well back, gripping the long handle-bars, which ran back to their waists, and crouching to avoid the wind. The witches' broom-sticks of our great-grandfathers were far less terrifying than this speed orgy, and the terrific noise and flashes as of lightning, which followed one another every second, making the race a very nocturne of petroleum -- a concert of concussion.
"Come up and look down on to the virage," called my friend in my ear, and I followed him up to a point in the very centre of the course, from which the descent to the grass plot in the middle was like the side of Murren, opposite the Jungfraus. Rrrrrrh! Here comes one of them! Bang! Bang! Bang! Flash! Flash! Flash! and as he passes under us the man on his motocyclette literally seems to brush the grass outside the track and to be at right angles to the wall of wood on which he travels. The speed was fearful, and before I could get my breath - for a second I had really thought the man and machine were doomed to death - he had rushed round the track an;d passed below us once again. The crowd by now was in a hubbub cf the wildest excitement. I could see hats, handkerchiefs and umbrellas waving madly, and every now and then; even above. the tumult of the motors, I heard a shriek of encouragement to the racers...
"Demester wins -- Demester!" (1) yelled my friend into my ear, pointing to the little figure which was now over a hundred yards away, and presently the bell clanged out to show that the last lap alone remained, and a few seconds afterwards a pistol's smoke was seen. . The report was quite inaudible. Four or five times round the track the motocyelettes went although the race was over, carried by the mere impetus of their enormous speed, and presently the man with the big speaking trumpet told us that Demester had won, and had broken the world's record, doing his six miles in 7 min. 34 2-5 sec., or, roughly speaking, forty-three miles an hour.
Extract from Racing at Buffalo, 1902
1) Two sources mispelled the name - Demester instead of Demeester
Sources: Trove NLA, Gloubik Science, Bourdache