Manufactured 1930 to 1933. Sales were over 700 in the first year, but dropped off dramatically as the economic crisis worsened. In total just under 1000 were sold.
Powered by a Sturmey-Archer 500cm3 engine, this was one of Germany's fastest production motorcycles
The sidevalve KR 50 was introduced in 1930, and later that year the KR 50 S appeared with an OHV 500cc engine from Sturmey-Archer. The same engine was popular with other German manufacturers including Horex, Hercules and Nestoria, and was fitted to the Soyer from France as well as Belgian and Italian marques.
Sturmey Archer was part of the Raleigh company, who fitted the engine to their MG 31 Sport.
With a bore and stroke of 79 mm x 101 mm giving 495 cc (the same as the sidevalve model), the OHV engine delivered considerably more power - 18 h.p at 4800 rpm. The bottom end was basically the same, but it had lighter pistons and a balanced crankshaft.
Lubrication was dry sump with an external oil pump, and the exposed rockers and valve stems were lubricated by oil mist.
The saddle tank had a capacity of 13 litres.
A German tester reported having frequently achieved 110/115 km/h on the street - very high speed for the time.
