Welded frame with larger diameter top tube for strength
Front Suspension
Telescopic forks
Rear Suspension
Swing arm, 2 shocks wiith dampers
Front Brakes
8 in. drum, leading shoewith snail cam shoe adjustment
Rear Brakes
7 in. drum with floating cams
Wheels
Steel, spokes
Front Tyre
3.25 x 18 in.
Rear Tyre
3.5 x 18 in.
Dimensions
Length: 2159 mm / 85.0 in.
Width: 737 mm / 29.0 in.
Height: 1105 mm / 43.5 in
Wheelbase
1372 mm / 54 in.
Ground Clearance
178 mm / 7 in.
Seat Height
813 mm / 32 in.
Dry Weight
140.6
kg / 310 lbs
Wet Weight
184 kg / 406 lbs
Fuel Capacity
UK: 18.2 L /
4.8 US gal
US:
9.1 L / 2.4 US gal
Standing 0 - 100 km/h / 62 mph
7.4 sec (B50SS model)
Top Speed
145 km/h /
90 mph
.
Introduced in 1971, the B50MX
(Motocross) was the last competition motorcycle announced by BSA, just as the
company’s efforts came to a close. Developed through the great success of the
BSA ‘works’ machines in motocross, and using bikes based on the B44 Victor, the
B50MX offered a strong and powerful 500cc engine. A new chassis design which saw
the introduction of an oilbearing frame and its extreme slimline aesthetic that
was enhanced by a beautiful tucked-in exhaust system ensured this machine’s
place in history as it was one of the rarest and most successful BSA MX designs
of the period.
The BSA B50 MX was the final competition motorcycle ever built by BSA, a
proud British motorcycle manufacturer who had built a staggering number of race
winning motorcycles over its decades long history.
As the name suggests, the B50 MX was the motocross version of the standard
B50. It was designed exclusively for off road competition with as much weight
saving as possible, the final production motorcycle tipped the scales at
approximately 300 lbs or 136 kgs.
The B50 is powered by a single-cylinder, four-stroke, air-cooled 499cc OHV
unit-construction engine producing 34 hp and sending power to the rear wheel via
a 4-speed transmission. The model uses a tubular steel duplex cradle frame with
oil stored in the top tube, and it has standard drum brakes front and back.
BSA produced the B50 in three distinct model variations, the BSA B50SS
(Street Scrambler), the BSA B50T (Trail), and the BSA B50MX (Motocross).
Production lasted from 1971 until 1973, after which time BSA ceased to function
but a small number of B50s were still sold rebadged as the Triumph TR5T Trophy.
Despite the relatively low production numbers the B50 did still enjoy some
successes on the race track thanks to specially modified bikes built by Mead &
Tomkinson in England. These bikes would win the Zolder 24 Hour race outright and
take class wins in the 1971 Thruxton 500 Miler and the Barcelona 24 Hours, they
also set a class lap record in the Production Isle of Man TT.
By the time BSA released the B50 series of motorcycles in 1971 the British
had enjoyed decades of dominance as one of the world’s leading motorcycle
producers, and one of the most successful builders of four-stroke, off-road
racing motorcycles.
It would be the late 1960s and early 1970s that would see this period of
success come to an end for the Brits, two stroke motorcycles from the likes of
Husqvarna and other European manufacturers had been chipping away at their lead
but it would be the arrival of fast, inexpensive motorcycles from Japan that
would mark the end of the British motorcycle industry.
Sadly for the B50 it wasn’t able to compete with the inexpensive,
lightweight, and very quick two-stroke motorcycles that had come to dominate
off-road motorcycle racing. The downfall of BSA and many other marques was
directly attributable to poor company management and product planning, whereas
the actual motorcycles themselves were often great.
The BSA B50 has now become a popular lightweight vintage scrambler with
plenty of torque and a much lighter, more manageable construction that makes it
easier to ride off road than other British off roaders of the era like the
Triumph TR6 and the Norton P11.