Description
This motorcycle is Lot 235 to be auctioned by Bonhams at The Spring Stafford Sale (The International Classic MotorCycle Show) on April 25th & 26th, please see the Bonhams Motorcycles Website for full details.
Auction Timings:
Lots 1 - 94 are to be sold from 14:30 on Saturday 25th April 2026.
Lots 201 - 353 are to be sold from 11:30am on Sunday 26th April 2026.
Public Viewing:
Available 25th & 26th April 2026 from 09:00 until 17:00, at The Staffordshire County Showground (The International Classic MotorCycle Show).
The David Plant Collection
** c. 1931 AJS 349cc Model SB6 'Big Port'**
Registration no. not registered
Frame no. M114509
Engine no. SB6/ 153??? & M5-114509 (see text)
** Gearbox no. RR0258**
Although it retained the 74x81mm bore and stroke dimensions of the 1920 Junior TT-winning prototype, the machine that brought AJS a remarkable Junior/ Senior double victory the following year had been extensively redesigned in the light of experience gained from racing. The production version, known latterly by the 'Big Port' soubriquet, made its debut in November 1922, offering near-racetrack performance for the road rider.
In September 1930, AJS's 1931 range was announced and for the first time the factory used 'Big Port' as an official model designation for one of its overhead-valve 350s. This was applied to the SB6, a three-speed lightweight variant offered alongside the similar size twin-port S6. The SB6's raison d'être was the favourable rate of taxation applied to motorcycles weighing less than 224lbs, though if the optional (and heavier) four-speed gearbox was specified the SB6 no longer qualified. Production of the SB6 continued at Plumstead after the Matchless takeover of December 1931, finally ceasing in 1934.
An older restoration now in need of recommissioning and/ or further restoration, the machine we offer is one of the last Wolverhampton-built AJS motorcycles. It should be noted that the engine number plaque has worn and it is no longer possible to discern the number's final digits; however, the engine does have matching crankcase halves which are stamped 'S1960'. The engine is also numbered M5-114509 to match the frame, this believed to be a non-factory stamp.
Following a period of inactivity, this motorcycle will require recommissioning and/ or restoration to a greater or lesser extent before returning to the road and thus is sold strictly as viewed. Prospective purchasers should satisfy themselves with regard to this motorcycle's completeness, history, authenticity, originality and mechanical condition prior to bidding.
There are no documents with this Lot. The engine turns over.
Key not required
All lots are sold ‘as is/ where is’ and Bidders must satisfy themselves as to the provenance, condition, age, completeness and originality prior to bidding. Visit the Bonhams Motorcycles website for all pertinent auction information.
