The BSA B50 was the last in a long line of successful machines from the Birmingham works, and marked the end of an era. It was manufactured for two years between 1971 and 1973, when the BSA marque left the forecourt leaving only Triumph and Norton to represent the once great British motorcycle industry.
Following success on the track, the production B50 displayed innovative features which manifest themselves in the form of Oil in the Frame technology, improved swinging arm adjustment, beefed-up engine, box type (waffle) exhaust, electronics contained in a single removable pod and better stopping power.
The design was radical, and it did not go unnoticed by the Japanese who in short order manufactured both small and large bore single cylinder street scramblers - typically the Yamaha XT250/500 and Honda XL250/500 of the mid to late 1970s.
The BSA street scrambler was available in 250cc and 500cc versions. The European models were available with 3 gallon steel tanks, whereas for the American market a smaller 2.5 gallon alluminum tank was standard. The bike was also available in Trail and Scrambles versions. By this point in the history of BSA most of the production was aimed at, and subsequently exported to, the United States. The Japanese had all but taken the English market and the sewing machine era had dawned, so called because the throaty boom of the British exhaust note had been replaced by the relatively quiet Japanese models. It was not uncommon for riders of these machines to swap the silencer for a short megaphone to increase the exhaust decibels, and hence their presence.
The Japanese onslaught into the British motorcycle market resulted in few of these BSA beauties seeing the English roads, though it was well-loved in the Scandinavian countries.
B50SS - GOLD STAR 500 Specification
500cc Single Cylinder OHV Engine
Alloy Head and Barrel
Welded Frame with Oil Containing Top Tube
Upswept Black Finish Exhaust
A Gold Star 500 won the 500cc class in the Thruxton 500 miler*, and the Barcelona 24 hours* and won the Zolder 24 hour Race* outright. A tough no-nonsense street scrambler which is as much at home off the road as on it. The Gold Star 500 has an extremely rugged race-proven frame, a willing 4-stroke power unit giving tremendous torque at low rpm - the right power at the right time. New colours for 1972 with polished front forks and hubs gave the machine a very attractive appearance.
*Entered by Mead & Tompkinson of Hereford, England and ridden by Nigel Rollason and Clive Brown.
BSA Sales Literature
From the pipe that's tucked inside the frame, to the muffler that's baffled away in back, from the racing frame that carries the oil to the single cylinder, 4-stroke power plant, these bikes have been proven feature-by-feature by John Banks, Britain's famous champion racer.
Instantly detachable electrics disconnect with a single plug that goes to a single-source, water-resistant box.
All-aluminum copy of John Banks' Motocross, six-inch front brake. On all models, except Gold Star 500-SS.
BSA GOLD STAR 500 SS. (B-50SS)
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Engine Type No. of Cylinders Max. Horsepower Max. Torque Bore/Stroke Comp. Ratio Transmission Carburetor Tire Size Front Tire Size Rear Front Brake Dia./Type Rear Brake Dia./Type Wheel Base Ground Clearance Dry Weight Fuel Tank Capacity Oil Capacity |
OHV 4-stroke 1 34 bhp @ 6200 rpm 28 ft. lb. @ 5000 rpm 84 x 90 mm 10; 1 4-Speed gearbox Amal 30mm concentric Dunlop 3-25 x 18" K70 Dunlop 3-50 x 18" K70 8" DLS 7" SLS 54" 7" 310 lbs. 2 ½ gals. 4 ¾ pts. |
Choose from three types: Street Scrambler, Trail, Moto-X. All bred-on-the-trail by John Banks, champion British rider.
John Banks riding on BSA, twice won Britain's national Moto-X championship and he helped BSA develop the features of these bikes. We took 500 ccs of British muscle, harnessed it in a four-stroke, single cylinder engine. We teamed it with a new, lightweight racing frame - a frame that contains and cools the engine oil, and eliminates the tank. Then we added new telescopic front forks that help keep you in control on any terrain; 3-way, adjustable, Girling shocks, double-shoe brakes, to name just a few of the features that make these 1971 trail bikes Britain's best. (In fact, the worse the trail gets, the better you like BSA.)
500 ccs of powerful performance, flowing from the smoothest, surest source you can get, the four-stroke, single cylinder, overhead valve engine. And every other feature is just as logically planned, including: inside-the-frame pipes, one compact source-box for electrics - with an instantly detachable plug, and the conical aluminum hubs. (Thank you, John Banks.)
(B-50T)
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Engine Type No. of Cylinders Max. Horsepower Max. Torque Bore/Stroke Comp. Ratio Transmission Carburetor Tire Size Front Tire Size Rear Front Brake Dia./Type Rear Brake Dia./Type Wheel Base Ground Clearance Dry Weight Fuel Tank Capacity Oil Capacity |
OHV 4-stroke 1 34 bhp @ 6200 rpm 28 ft. lb. @ 3000 rpm 84 x 90 mm 10:1 4-Speed gearbox Amal 30mm concentric Dunlop 3-00 x 20" Trials Dunlop 4.00 x 18" Trials 6" SLS 7" SLS 54" 7½" 298 lbs. 2½ gals. ( aluminum tank) 4¾ pts. |
(B-50MX)
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Engine Type No. of Cylinders Max. Horsepower Max. Torque Bore/Stroke Comp. Ratio Transmission Carburetor Tire Size Front Tire Size Rear Front Brake Dia./Type Rear Brake Dia./Type Wheel Base Ground Clearance Dry Weight Fuel Tank Capacity Oil Capacity |
OHV 4-stroke 1 38 bhp @ 6200 rpm 35 ft. lb. @ 5000 rpm 84 x 90 mm 10:1 4-Speed gearbox Amal 32mm concentric Dunlop 3.00 x 20" Sports Dunlop 4.00 x 18" Sports 6" SLS 7" SLS 54" 7½" 240 lbs. 1¼ gal. (aluminum tank) 4¾ pts. |
Sources: Cedric Norman Archive; BSA Catalogue.
