Praga BD OHC 500cc. This motorcycle was built in 1929, the first year of production. Production of 500cc model was ended in 1933. Restored, in running condition.
"Praga was a famous car maker in pre-war Czechoslovakia who, in 1929, took over the under-capitalized BD motorcycle works, thereafter re-naming the range ‘Praga BD’. BD stood for Breitfeld and Danek who had made the absolutely superb, J. F. Koch – designed ‘double-knocker’ twin-overhead-camshaft, 84 mm x 90 mm, unit-construction single, so good that it had great success in most branches of motor cycle sport, despite being produced in the relatively small numbers associated with such high-end engines. This unit was mounted in a robust and up to date chassis, the whole being carefully made and well-equipped. Praga themselves ceased production in 1935 making them rare items..." (from bonhams.com)
Above: 1930 photo of Jaroslav František Koch riding his motorcycle