1932 BSA B31/2 250cc

“The BSA 2.49HP OVH introduced last season has proved an exceedingly popular and successful model. In first-class trials during 1930 it won four Challenge Cups and numerous gold medals and first-class awards, and invariably made the fastest time in its class in acceleration tests. It was this model which a lady rode triumphantly through the international 6-Days Trials without losing a mark!”

BSA B31/2 w/ Lucas Magneto and 6 V Lighting Set, originally priced at £47, 17 Shillings and 3 Pennies


Birmingham Small Arms offered 12 models in their Catalogue in 1931/1932, right from the entry level 2.49HP B31/2 right to the 9.86HP V-Twin G31! The B31-2 or more commonly known as the 2.49HP featured its Chromed Fuel tank with Green Top Panel, Hand Change 3 Speed BSA Gearbox and enamel blacked frame (As advertised).

This fine machine is beautifully presented and prepared by our expert engineers. Whilst in our care, lots of work both mechanically and cosmetically has been carried out to achieve what you see today. A machine worthy of any collection - whilst having the capabilities to safely cruise the country roads! Surprisingly well house-trained, if you ever wished to have the machine as an ornament in the kitchen or man-cave!

An extended service that has been carried out in house, sees all oils replaced with quality low-detergent fluids and a replacement spark plug. It's clear that the previous owner has invested heavily in hours and funding to what you see today.

The top-end, valve gear and oil feeding components have been stripped, overhauled and rebuilt with top quality high temperature ZX1 Grease, this will ease the level of on-road maintenance that is otherwise required from a machine such as this.

Inside the engine, the barrel is freshly crosshatched, the piston crown polished and rings look to be of new condition which can only indicate that the engine has been rebuilt - when running, the engine burns no oil with no unwanted mechanical noises to note. 

A machine of this age and calibre will require a certain level of maintenance both on-road and off road - a certain level of engineering understanding and skills is definitely recommended when owning a machine such as this. Please read our short disclaimer at the bottom of this listing - of course, we’re more than happy to answer any questions you may have.

The Tanks interior has been renovated in-house, using paint safe cleaners and use of our phosphation solution to recreate that brand new grey tank interior.

The bikes Girder Style front suspension operates well and provides good dampening with general road use, the shafts and adjusters have minimal play and good operational movement.

Our technicians have recommissioned and restored its original AMAL Carburettor with a new float needle, gaskets and O-rings. Ultrasonically cleaned and rebuilt. This creates an easy start with all other starting aids. The Machine runs and ticks over well and has performed well on its short road trip.

The bike's paintwork is of a very good standard, and has been renovated well with professional polishes to replenish its shine and protect it for time to come! Mudguards, Frame, wheels and general tin-work is powder coated in finish, which gives the illusion of thick enamel as it once would have been out of the factory.

Control cables have been replaced throughout which gives a great level of attention to detail to the bike. The original Throttle/Advance/Retard lever has been assembled and operates very well  - but of course a 7/8 twist throttle grip can be a arranged to replace this if you so wish.

The Mag-Dyno has fantastic output and jumps a spark tester with ease. The external body has signs of renovation as too yellow loosen markers on fasteners - we would like to say that the unit has been rebuilt recently but unfortunately no paperwork or receipts to confirm - as too with engine works.

The electrics have been fully overhauled and tested through, a newly supplied Lucas 6V battery and Battery box have been installed which offers the rider lighting capabilities for trips returning from the pub! Lighting positions on the headlamp are brilliant - Lights Off, Lights on with use of the Dynamo, Lights on with use of Battery and Dynamo and finally - Lights on with drain purely from battery power! Why you would want this flexibility is beyond us - but the choice is yours!

A Fascinating full history is supplied with the bike, The bike of course rolled off the B.S.A production line in 1932 where it was first registered. Its first owner was not until 1946, in Libberton, Droitwich. 3 Owners Later… the machine finds itself with a gentlemen by the name of Albert Edward Earthy, Based at No.1 ESSD H Squadron, RAF HoneyBourne, Worcestershire. Who insured the vehicle third-party for £4, 4 Shillings.

The bike also comes with a Full Internal Safety Inspection (MOT Level) 

This is a truly fascinating opportunity to attain a piece of the backbone of British Engineering.

Small Disclaimer: The Machine available is 90 years old this year, the technology that is on-board a vehicle of this age is that of 1930. The simplest of AMAL Carburettors is crude to say the least, and by pure design a bowl of petrol resting at just the right height to the entrance of the engine - to be pulled in by vacuum. The Carburettor will require attention both on and off road - whether that be regular cleaning, or manually seating the float needle after flooding. A certain level of understanding of carburettors and combustion should be either learned or known to own a vehicle of this age.

The B31/2, although wet sump by design, is not a total loss system. The top end of the engine is essentially open to the sump and will flow passed the rockers, onto the valve guides and springs on to the top of the hot engine and burn off. Oil will be present at all times on the outside of the engine, and will require a drip-tray, (Only when stored warm.) The machine is otherwise gasketed well, and doesn’t leak oil when cold.

Recommended by B.S.A themselves, that external rockers be oiled manually every 25-50 miles of general road roaming, and camshafts to be greased with a grease gun every 250 miles. Although we offer both Servicing & Maintenance packages alongside our retail department, a certain level of “hands on” skill is always recommended, or the willingness to learn at a minimum.

A level of concentration is to be allowed when riding the machine also, General regulation of both advance/retard levers, and oil pressure gauges (Situated on the crankcase) is to be kept an eye on at frequent intervals to save engine damage. Once the machine is gotten used to, its a pleasure to roam the country roads with grace and elegance, using pure toque instead of revs - to sit at 2,500 RPM at 40-45MPH.

Copies of the original owners manual can be documented with the sale - for your peace of mind. We’re also more than happy to explain starting and running procedures.


A comprehensive Safety Inspection has been carried in house - ensures each and every detail has been checked for safety and quality assurance.

Although a viewing is always recommended - we can provide a full video walkaround of the running machine through WhatsApp upon request. We can also arrange for the bike to be delivered at a cost of £1 per mile one way from Framlingham Area.

Feel free to get in touch "over the phone" preferred if you should have any questions - we would be delighted to hear from you.


£6,850.00 – Viewing always advised / Part Exchange Considered.

BSA B31/2

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