Description
BSA 1949 A7
The BSA A7 was a British motorcycle manufactured by Birmingham Small Arms Company (BSA) at their factory in Armoury Road, Small Heath, Birmingham in 1946.
The 495cc BSA A7 continued in production with minor modifications until 1961.The 495cc twin cylinder engine produced 26bhp and was capable of 85mph.
A single camshaft behind the cylinders operated the valves via long pushrods passing through a tunnel in the cast iron block.
This system needed a considerable number of studs and nuts to fasten down the cylinder head and rockerboxes, many of them deeply
recessed and requiring well-made box spanners or the (then uncommon) sockets.
Most motorcycles of this period tensioned the primary chain by drawing or rotating the gearbox backwards on a hinge with threaded rods, this was known as pre-unit construction. The first A7 featured a fixed gearbox, bolted to the back of the crankcase, and an internal tensioner for the duplex primary chain.
This gave it the appearance of unit construction and pioneered the system later used in unit-construction engines (eg BSA C12/C15, BSA B40, Triumph 3TA and on).
However, in 1954 a re-design reverted to the older system. The electrics (as was universal for larger British motorcycles of the period) consisted of two independent systems, the very reliable and self-contained Lucas magneto, with a dynamo generator to charge the battery and provide lights.
Carburation was a single Amal remote float Type 6 until 1955 when it was upgraded to a 376 Monobloc.
This BSA A7 is very nicely restored and runs well.