The BSA Gold Star is a motorcycle made by BSA from 1938 to 1963. They were 350 cc and 500 cc single-cylinderfour-stroke production motorcycles known for being among the fastest bikes of the 1950s. Being hand built and with many optional performance modifications available, each motorcycle came from the factory with documented dynamometer test results, allowing the new owner to see the horsepower produced.
In 1937, Wal Handley lapped the Brooklands circuit at over 100 mph (160 km/h) on a BSA Empire Star, and was awarded one of the traditional Gold Star pins for the feat. That inspired BSA to produce the BSA Gold Star.
The first Gold Star was an M24 model. It had an alloy 496 cc engine, an Electron alloy gearbox, and a rigid frame made of light tubes devoid of sidecar attachment lugs. This model continued up to the start of World War II.
1948 YB32 and YB34
After the war, the all alloy 348 cc B32 and 499 cc B34 Gold Star were released, with a very large list of optional components. Once ordered the bike was assembled by hand, and the engine bench tested. They were 20 lb (9.1 kg) lighter than the comparable cast iron barrel and head B series single. They were successful in the 350 class from 1949 to 1956. They could be specified in tourer, trials, ISDT, scrambles, racing or Clubmans trim. The YB is taken from the beginning of the engine number – YB is 1948, ZB is 1949 on.
1949 ZB32 and ZB34
1949 CB34 Gold Star
The 499 cc B34 Gold Star had a modified crankshaft and a different design main bearing. The 350 continued. Plunger frames were available as an option. In 1950 both received larger front brakes. In 1952 the 500 gets a new Bert Hopwood design head, and the 350 had a new head of that design the following year.
1953 BB34 and BB32
In 1953, a swingarm duplex frame was introduced,although rigid and plunger frames were still available, along with an improved gearbox.
1954 CB34 and CB32
1954 CB32 Gold Star
An optional CB engine was given more and squarer finning, a stronger crankshaft, a shorter connecting rod, oval flywheels (500), improved valve gear, and an Amal GP carburettor.
1955 DB32 and DB34
The DB Gold Star had an improved oil feed to the crankshaft, and finned front brakes. If the buyer specified Clubman cams and timing, he also received a special silencer. At the end of this year the BB and CB models were discontinued. The 350cc DB32 continued in production until 1962.
Motocross version from early 1960s
The 500 cc DBD34 was introduced in 1956, with clip-on handlebars, a finned alloy engine with a newly designed head,chrome plated fuel tank, 38 mm ( 1 1/2" ) bell-mouth Amal carburettor and swept-back exhaust. The DBD34 had a 110 mph (180 km/h) top speed. The Gold Star dominated the Isle of Man Clubmans TT that year. Later models had an ultra close-ratio gearbox (RRT2) with a very high first gear, enabling 60 mph (97 km/h) plus before changing up to second. Amongst the options available were a tachometer and a 190mm full width front brake that gave a larger lining area than the standard 8" single sided unit. A scrambles version was also offered.
In 1954, BSA wanted to win the prestigious Daytona 200 race. During the 1950s, the race was run partly on asphalt and partly on the beach at Daytona. A team of works prepared Gold Stars and A7 Shooting Stars were entered. The race was won by a Shooting Star with a Gold Star in 3rd place. A replica of the works Gold Star was offered to the public. The specification included a rigid frame, which saved 50lbs over the swinging-arm frame. Engine modifications included using a 350cc head, which had a better downdraught angle, machined to 500cc dimensions and fitted with a large inlet valve. The engine produced 44bhp. The model was also offered in subsequent years.
A swining arm version, known by the factory as "USA Short Circuit" was also produced in 1956 and 1957.
Gold Star Catalina
In 1956, Chuck Minert won the Catalina Grand Prix on a modified Gold Star. (The Catalina Grand Prix was a popular 100-mile race on the island of Santa Catalina off the coast of Los Angeles. In 1956 more than 1,000 bikes started the race.) Modifications included a larger fuel tank, an air scoop on the front brake and a 19" front wheel.
US west coast BSA distributor, Hap Alzina, persuaded the factory to produce a replica named after the race. The Gold Star Catalina was manufactured from 1959 to 1963.
End of production
Towards the end the Gold Star was only offered in scrambles, or Clubmans trim. In 1963 Lucas ceased to produce the magneto used in the B series, and that line of singles was ended. The demise of the Lucas magneto was a prime reason that BSA and Triumph reconfigured their pre-unit-construction parallel twins into engines with integral gearboxes, simultaneously converting the ignition system from magneto to battery & coil. The Gold Star was not considered for progression to unit-construction, and instead the 250 cc BSA C15 was developed (via the B40) into the 500 cc B50. Although the B50 never attained the kudos of the DBD34, a B50 fielded by Mead & Tomkinson once held the class lap record in the Production TT, as well as gaining results at the 24-hour endurance races the Le Mans Bol d'Or and at the Montjuïc circuit in Barcelona.CCM used BSA B50 bottom ends in their early specials.