BSA’s Fabulous Gold Stars

Story by Graham Clayton// Photos by Graham Clayton
July 1 2008

Brooklands, the world’s first purpose-built motor sports racing circuit, opened in 1907, the same year as the running of the very first Isle of Man TT race. The 2.8-mile (4.5 km) banked circuit, located in Surrey south of London, was an oval-type shape and made of concrete. Its owner, H. L. King, intended it to be used for both racing and for the testing and development of high-speed machines by British manufacturers.

Thirty years later in June 1937, British racer Wal Handley won a coveted gold star lapel badge awarded to a rider who could lap the Brooklands circuit at the ton (100 mph) or better. Handley rode a highly tuned BSA M23 500 cc Empire Star single to a flying lap of 102 mph (164 km/h).

The following year, BSA introduced a replica model of Handley’s bike, the M24 Gold Star. This new model came with a tuned, alloy version (cylinder head and barrel) of the Empire Star’s push-rod single cylinder engine, complete with polished internals and special performance enhancing parts. Running on gasoline, the M24 developed 28 bhp and could nudge 90 mph in top gear. An optional version with 12:1 compression that ran on alcohol generated 33 bhp and was a genuine ‘ton-up’ bike. As a cost-saving concession, the frame of the Gold Star differed little from the standard item, but that frame design was up to the task.

The introduction of the Gold Star model marked a significant change of events for the BSA (Birmingham Small Arms) concern. It had given up competing in the Isle of Man after a few early disappointing results, but during the inter-War period established a good reputation for itself in both trials and endurance event competition winning many trophies.

BSA had also earned a good reputation with its workhorse M series side-valve singles that continued in production until 1963, and were the last side-valve machines built in the UK. The company built well over 120,000 side-valve models for the military during WWII and in doing so became a well-known name to the next generation of bike owners, many of whom rode them while in military service.

After the war, BSA introduced a competition 350 cc OHV single called the B32 that was originally intended for trials use, but proved to be a capable mount as a road racer. In 1947, the English firm introduced 499 cc versions of the bike designated B33 and B34.

By now the bikes were fitted with an early version telescopic fork up front, but still had a rigid frame and a sprung saddle at the back. Gradual improvements to the BSA line saw first the introduction of a plunger rear end in 1949, and then the switch to a full swinging-arm and twin shock rear suspension set up in 1950.

In 1948, BSA introduced the 350 cc ZB32 Gold Star, followed in 1949 by the introduction of the 500 cc ZB34 Gold Star. These bikes were very fast for their day and came with an extraordinary range of options; including a choice of four camshafts, four compression ratios, three gearing options, plus assorted fuel tanks, exhaust systems and wheels. These options enabled the buyer to order a ‘Goldie’ designed for the type of riding that he (or occasionally she) planned to do, namely for street use, road racing or scrambles.

In 1949, a highly tuned 350 Gold Star won the Clubman’s TT in the Isle of Man at an average speed of over 75 mph running on 73-octane fuel, the so-called ‘pool’ gasoline that was used in the UK at that time. This would be the first of numerous such wins.

Each year BSA introduced refinements and improvements to the Gold Star models based on lessons learned through various forms of competition. One of the more truly remarkable aspects of BSA’s high performance single was its ability to be successfully adapted for all manner of motorcycle competition, including trials, scrambles, road racing and, on this side of the Atlantic, even flat track racing.

Each Gold Star came from the factory with a certified dynamometer reading for the power output of the engine. This varied of course according to the option level chosen and type of power delivery desired by the owner.

Clubman road racing was very popular in the UK from the late forties through the 1950s. Competitors in these events raced modified street bikes that otherwise were their daily transport. They would ride the bike to the race track, remove the lights and other street items, race for the weekend, then reinstall the street parts and ride home. Such bikes offered affordable racing to those who couldn’t afford to shell out for a high-end overhead cam race bike, plus own another bike for street use.

BSA’s Gold Stars proved especially competitive in such road racing and did much for the reputation of the company. Some might argue that they were too successful for their own good. In 1955, no less than 33 of the 37 bikes entered in the 1955 Junior Clubman’s TT race were 350 Gold Stars. Perhaps as a result, the 1956 Clubman’s TT would be the last.

By now BSA had become the largest motorcycle manufacturer in the world, building as many as 75,000 bikes a year.

In 1956, BSA introduced what was to become the most famous model in the Gold Star line, the DBD34 Clubman’s production racer. This bike, in effect a thinly disguised road racer, embodied still further improvements gained from competition. BSA’s famous chief designer, Bert Hopwood, oversaw the development of this model.

New modifications included steeper steering geometry, a new swing arm and twin shock rear suspension, a bigger front brake, an ultra close-ratio gearbox, large-finned cylinder barrel and a big Amal 1-1/2 inch GP carburetor with an open intake. This bike had the unmistakable lean look of a production racer with its clip-on handle bars, chrome-sided gas tank, rear-set foot-pegs, raised head lamp and swept back ‘Goldie’ megaphone exhaust. Weighing in at 384 lbs (174 kg) and putting out 42-43 bhp at 7,000 rpm, the new Clubman’s Goldie would do a genuine 110+ mph (177+ km/h) in stock form.

The DBD34 was the original ‘hooligan bike’; loud, fast and in your face. Needless to say, they sold like hot cakes and were the bike of choice for the new evolving café racing phenomenon that was taking hold in the UK.

BSA offered a more civilized standard version Goldie for street use fitted with a smaller 1-3/8 Amal carb, a more practical wider ratio gearbox and a motor that produced five less horsepower. This model was still capable of doing an honest ‘ton,’ but was more rider friendly. Quite a few owners reportedly chose to retrofit the bigger Amal carb to this model for extra top end.

BSA continued to build the Gold Star for six more years and sold them to fast bike enthusiasts all over the world. Many of those machines are still being ridden to this very day.

The last year for Goldie production was 1963. By then BSA had come to the conclusion that the big single was no longer economical to produce, and it made the decision to focus future development efforts primarily on its twin-cylinder models.

 

Living With a ‘Goldie’ on the Street

BSA’s later model Gold Stars were delivered in a fairly high state of tune, especially the DBD34 Clubman’s model, and could be a real handful to ride on the street. Little more than a disguised racer with lights, these Goldies were in their element when kept on the boil, but low speed around town stuff was not what they were meant for and they could really act up.

Models fitted with the close-ratio competition gearbox and the big GP carburetor had to be kept above 3,000 rpm to generate any kind of power, and would stall if the revs dropped below 2,000. The first gear was so tall that 60 mph was reportedly reachable before changing up.

Like many big singles, starting a Gold Star requires a set procedure. Failure to stick to the procedure can often lead to flooding and considerable difficulty getting the bike to start.

Cyril Brazier is a vintage Brit bike enthusiast who lives in southwest Ontario. He also happens to be the proud owner of two 500 cc BSA Gold Stars, a 1955 DB Clubman and a 1957 DBD34. I asked Cyril what the Goldies were like to live with on the street?

Cyril likes a big single and prefers riding them to either BSA-Triumph vertical twins or their 750 triples, examples of which also reside in his garage. The Gold Stars, he says, are better handling than a Triumph Bonneville, though perhaps not quite as good in that department as the big Norton twins.

The BSA singles are certainly at home at speed on an open twisty country road. That is their element and they thrive in it. Cyril says that their road holding ability is really good, though not always in the same league as modern era bikes. Still, for a fifty-year-old bike, the Gold Star is stable and predictable at speed, and does make for a safe and fun ride.

He says that riding a Gold Star with the close-ratio gearbox and the big GP carburetor, which he did earlier, presented real problems whenever you had to do any slow speed stuff or even stop. You had to constantly keep the revs up, and blip the throttle repeatedly when pulling up to a stop sign or traffic light. This was hard on the clutch and necessitated careful maintenance.

Early on Cyril developed a habit of slipping his Gold Star into neutral before coming to a stop. This would save clutch wear, but if you didn’t do it before coming to a full stop then hunting for neutral gear once standing could be a real bear.

Cyril’s DBD34 is fitted with the standard 4-speed gearbox for road use and uses a big engine sprocket. This transmission is a lot easier to live with than the close-ratio box. He also ditched the bike’s original 1 1/2-inch Amal GP carburetor, replacing it with a 38 mm Mikuni (same size as original) that transformed the beast.

Gone is the spitting back, stumbling and other carburetion misbehaviour of the GP. The bike now idles at around 500 rpm, pulls smoothly and strong through the rev band, and delivers 50 mpg (17.8 km/liter) on high-octane gas.

This past winter Cyril spent some time in Florida where he rode his Gold Star daily and chalked up another 2,000 miles on the street without a hitch. I asked him what speeds he typically rode at. He said that he likes to keep the engine in the 3,500-4,000 rpm range most of the time, with highway speeds of around 60-65 mph (100-110 km/h). The bike will run happily all day like that.

Cyril’s bike retains its six-volt electrics, which haven’t been a problem. The system yields adequate lighting for road use and is low maintenance. Overall, he has had few problems with his two BSA singles. He has heard of people having major problems with the riveted crankshafts that BSA recommended rebuilding after every 20 hours of racing, but he’s had no such problems.

Cyril runs 20:50 multi-weight oil in his Goldies, while some other Gold Star owners that he knows prefer to run straight 50 weight. Oil leaks have not been a problem for him, though he points out that the big singles are known for wet sumping if the engine is left to stand, an inconvenience that he has experienced.

I asked Cyril what is the best part of owning a Goldie, aside from the pleasure of riding them? Cyril says that it probably is the reaction and admiration that he frequently gets from knowledgeable people when they realize that his bike is actually a 500 cc Gold Star. The bike’s big-fin single cylinder motor, plus that gold star and red tank badge, makes the famous old model unmistakable.

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