 Power for the D’Yrsan "Model A" came from a Ruby 4-cylinder 6 HP side-valve engine of 904cc.At the 19th Paris Motor Show, which took place in October 1924 ahead of the 1925 model year, the "Model A" was complemented by the D’Yrsan "Model BS", its engine size increased to 972cc, now featuring overhead valves.Both models sat on a wheelbase.