SM 500
The SM Motors and Motorcycles Factory (Wytwórnia Silników i Motocykli SM) was established in Warsaw in 1934, on the initiative of two young engineers, Alfred Schweitzer and Edward Mandelot. These men were the creators of the first sports motorcycle produced in the Poland. The first series consisted of only 10 units, with the nature of production focused on the individual method of assembling each motorcycle, with full interchangeability of mass-produced parts.
The SM name is likely the initials of the the creators, Schweitzer and Mandelot.
The actions of the manufacturers demonstrates concern for future users. The prototype of the motorcycle was carefully developed. Design work began in 1930 - 1931, and the construction of the prototype (in Wytwórni Silników i w Warsztatach Mechanicznych) was completed in 1933.
The desire to ensure reliable operation of the vehicle is demonstrated by the use of components were sourced from established manufacturers - the trapezoidal fork from Brampton, the carburetor from Amal, and the electrical system from Bosch.
The SM had a single-cylinder overhead valve engine with a displacement of 498 cc, developing 18 hp at 4,000 rpm.
The cylinder head has large diameter valves and hairpin springs. The engine was lubricated under pressure, and was modeled on the excellent English Blackburne lubrication system.
The drive was transmitted through a dry, single-plate clutch, a three-speed gearbox controlled by foot or manually, and a drive shaft with a flexible joint. The vehicle had a tubular frame, closed, rigid rear suspension and a trapezoidal front fork with a central spring and friction shock absorbers.
Interchangeable wheels were easily disassembled by removing the axle - noteworthy is the large diameter of the brake drums, which were coupled with each other and controlled by foot. The rear brake drum was integral with the wheel hub, on the drive shaft by the gearbox, as in many foreign designs.
The SM weighed 150 kg. Solo, it developed a speed of up to 130 km/h. Fuel consumption was not high and amounted to 3.5 l/100 km.
Out of a dozen or perhaps several dozen SM motorcycles built in the years 1934-1936, it seems none have survived. So, if someone encounters a motorcycle with characteristic lugs in the crankcase and the main gear cover in the form of intertwined letters SM, you can be sure, the most interesting and probably the most luxurious Polish motorcycle, the production of which, unfortunately, did not develop, but for reasons not attributable to the constructor and manufacturer.
Source: Polish History Archive
Notes.
1. Emil Ryszard Schweitzer, Alfred's father, was a successful motorcycle racer. Information on the family and their various business interests at https://www.polacyzwyboru.pl/de/helden/familien/schweitzer.
2. Motocykl sportowy sm 500: https://audiovis.nac.gov.pl/obraz/61116/3920e6f7956f423e84328a3dcd7dff04/
