The 1924 249 cc Model B, known as the "Roundtank" had a side-valve single cylinder engine. Introduced in January 1924 BSA it produced an enthusiastic response from the trade press and potential customers, not least due to its price of less than £40.
The Post Office placed a substantial order for the Roundtank in 1924, after seeing it perform in a publicity stunt climbing Mount Snowdon in Wales in less than 30 minutes. These were used for telegram delivery.
The machine had a maximum speed of 45 mph, weight 170 lb and fuel consumption of 120 mpg. It did well in the market - very, very well. Over the following 12 months BSA sold around 15,000 of thes motorcycles, and over the following 5 years produced in total 35,000 of them - not all of them Roundtanks, as they fitted wedge-shaped tanks to later models.
The Model B had 24" wheels, a two-speed gearbox and a mechanical oil pump. Specifications, 1925 BSA Motorcycle Catalogue
Tanks: Round in 1924, 1925 and 1926. In 1926 the same model with a wedge tank was offered, and by 1927 the round tank was dropped. 1929 saw the introduction of saddle tanks.
Sources: yesterdays.nl, factory literature.
