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eff Smith was born in Colne, in Lancashire, England and stumbled upon motocross almost by accident, having dabbled first in the discipline of trials riding where he won two national championship titles. Riding for BSA he had ridden just a handful of (scambles) motocross races when his bosses at BSA asked him to ride the Dutch GP as part of the factory team in 1954. And it did not take long for him to get noticed in the motocross world, winning his first GP on his debut. After a couple of years in The Army, he returned to the BSA factory where he also worked, and switched his attentions to motocross GP’s and in 1964 became Great Britain’s first ever world champion, riding a British-built BSA. But how different was his factory bike compared to the rest of the bikes he was up against? The BSA B40 was originally a street bike but it was also an engine that BSA supplied to the military. Considering Smith was racing in the FIM 500cc Motocross World Championship BSA did not actually make a 500cc engine. Instead, the B40 factory bike started life as a 350cc and was bored and stroked to 420cc capacity. At the time, BSA and the 4-stroke market were being pushed to the limit of their capabilities with the threat of the Japanese 2-Strokes that were gaining traction being faster and much lighter. So, pushing the motor out to 420cc was the only way to go. But this kind of intuition came about as a result of another model that BSA produced, the C15, as Jeff Smith recalls: ‘The C15 was a push rod 250. Basically it was a motocross engine specifically made for racing in the 250cc class. It was obviously much lighter, and we realised we could put a 250cc into places on the track where you could never put the bigger Goldstar, which Arthur Lampkin and I were using at the time. So, around 1960, ’61, ’62
when we raced the 250cc world championship, I think we experimented by putting the 420cc engine into one of the 250cc frames to start with, and then we did whatever we needed to do, to strengthen the frames, or to change them to accommodate the 420. From there we started thinking in terms of making a much lighter, but not so powerful machine for the 500cc class, and the B40 was a derivative to some extent of the 250cc; it was a 350cc made basically out of the 250cc crank case, and so that was immediately a much lighter engine than a Goldstar, and so we started playing with the engine and pushed it out to 420cc and that’s the machine that I used in the 1964 500cc World Championship.’ During this iconic era of motorcycling, experimentation was commonplace, none more so than for BSA whose background was in the military. BSA stands for ‘Birmingham Small Arms’ and the factory on Armoury Road, had unrestricted access to all kinds of different materials. Motorcycles back then, particularly 4-Strokes were extremely heavy, so if anything could be done to make them lighter, then it was greatly welcomed. And Jeff’s 1964 B40 was the epitome of that. Magnesium was used for fun it seemed, with the lightweight material being used on a multitude of parts; hubs, crankcases and fork legs would normally have been made from aluminium, but on the B40 those were all Magnesium items. Titanium nuts and bolts were used all-round; the steering head and column were also made from Titanium and believe it or not, so too were the front and rear spindles. The swinging arm pivot though was aluminium. There was also talk of BSA experimenting with Titanium handlebars. Was this true Jeff? ‘Yes I did actually; I raced with Titanium handlebars and had a nasty accident in Czechoslovakia in the grand prix there, and one half of the handlebar fell off, or broke because
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