What is the quintessential British motorcycle?

You’ll get a lot of answers to this question, but generally speaking, it’ll be some hot-rod parallel twin. A Norton Commando, a BSA Lightning, or maybe even something exotic like a Vincent V-twin.

I’ve got another suggestion—I think the quintessential British motorcycle could be the BSA Bantam, like this 1955 example up for auction this weekend at Bonhams. This little two-stroke wasn’t even a made-in-the-UK design, at least not originally, but the Brits sure made good use of it during a 23-year production run. It was to motorcycles what the VW Beetle was to cars, and no wonder: They both had their roots in Germany’s populist vehicle design.

German ancestry

Production of the BSA Bantam began in 1948, which was roughly when the entire British motorcycle industry was gearing back up for civilian production after years of supporting the war effort. It was a logical time to introduce a new model. However, the BSA Bantam wasn’t exactly all-new; it was a warmed-over take on the DKW RT125, a German-built two-stroke motorcycle with its origins in the early 1930s.

The DKW RT125, a cornerstone of Europe’s pre-war motorcycle industry. After World War II, it was copied widely. Yamaha, Harley-Davidson, BSA and factories in the USSR all copied the excellent two-stroke design.

DKW was a major player in pre-war European motorcycle manufacturing, and the RT125 was a big part of that success. The RT125 was a two-stroke, with a loop-scavenging system that used the fuel/air mixture from the intake to push exhaust gases out of the cylinder in an efficient manner. This system was the brainchild of Adolf Schnuerle, and exclusive to DKW at that time, giving its bikes a performance edge. You need all the help you can get, when your piddly pre-war two-smoker is making around five horsepower.

(If you want a video explanation of this process, which is now common in two-stroke design, see here. Kevin Cameron has the brainiac explanation here).

And then, WW2, The Big One. The RT125 wasn’t an iconic Wehrmacht vehicle like the BMW R75 and Zundapp KS750 sidecar rigs, but the German war machine made use of the little DKW as well. Despite the “mailed fist” reputation of Blitzkrieg warfare, much of the German military effort still used horsedrawn wagons, and a diminutive two-stroke offered plenty of advantages over a draft horse (at least, until the Allies started bombing your fuel supply …). Supposedly, Germany and other Nazi-controlled territories were producing more than 200,000 motorcycles a year by 1938—a big number today, but almost staggering when you consider the lower population of pre-war Europe. Bikes like the DKW RT125 were a big part of that production.

Off to England

We all know how World War II ended, and in the post-war scrum, while taking a break from hanging war criminals and arguing over who owned Berlin, the Allies divided up German assets as war reparations. Except, there wasn’t much left to take besides the land itself, as strategic bombing by day and carpet bombing by night had smashed most of the nice things. What to do? One thing the Nazis had going for them was, they had lots of great technology, even if you don’t believe all those flying-saucer, military-base-on-the-moon rumours that Weekly World News used to print, next to Bat Boy’s adventures.

Along with domestic sales, BSA sold the Bantam all over the world. Production ran to at least 250,000 units; some believe more than 500,000 were sold. And, that’s just BSA’s DKW copies, not counting the other factories that also copied this engine.

While the Americans and Brits were understandably keen to capture the greatest minds of German’s V2 program before Stalin could do so, they weren’t just concerned with rocket scientists. They also realized the practicality of the DKW RT125 design, and took those blueprints for themselves.

In the decades following, the RT125 became the most-copied motorcycle in the world, with each continent making its own variations on the theme. Factories in the Soviet Bloc were soon cranking out copies of the machine. In the US, there was the Harley-Davidson Hummer. In the UK, the BSA Bantam emerged, carrying the DKW design into the next generation.

Ch-ch-changes

BSA made some major changes to the DKW design over the Bantam’s production run, starting with the first generation of made-in-England machines. Instead of going with Germany’s sensible gearshift-on-the-left arrangement, BSA flipped the design drawings and put it on the right-hand side, just like all the other Brit bikes of that era. The bike’s bottom end was a mirror of the original DKW arrangement.

There were many variations of the Bantam platform, with the later 175 cc models the best of the lot. Photo: Manx Norton

That was just the start. BSA built the Bantam through 1971, and made many more changes over the years. The final years of production saw the engine big-bored all the way to 175 cc. This version of the engine made just under 13 horsepower, a vast improvement over the original BSA configuration, which made just under 5 horsepower. It had a three-speed gearbox, just like the original, although BSA later developed a four-speed gearbox, as well as high-compression top ends, improved cooling fins and other minor tweaks to the engine that boosted performance. BSA also used a wide variety of electrical systems on the Bantam throughout its production.

Aside from the single-cylinder engine, there were other major changes to the chassis, with upgraded rear suspension perhaps the most noticeable. Originally a hardtail with sprung seat, like many other pre-war designs, the BSA developed a version with a plunger-style suspension, and then a proper swingarm.

In fact, the BSA Bantam served as the basis for some of the first proper post-war dual sport models, including trials versions and the Bushman scrambler. It served as a cornerstone of England’s motorcycle scene as an affordable bike to buy, and an affordable bike to run as daily transportation. Fuel consumption was modest, and the bike was capable. It didn’t have the power and machismo of the larger British twins and thumpers, but BSA built hundreds of thousands of these machines. They’re still readily available on the used market today, for not-silly prices, and while you wouldn’t want to ride one on the highway, they’re still lots of fun at slower speeds.

Likely to sell for under $2,000 US, but in the UK. Similarly affordable examples should be available in North America, without the hassle of trans-oceanic shipping. Photo: Bonhams

This bike here?

The bike in these photos is up for auction through Bonhams, on October 9 (place your bid fast, if you want it!). It’s a 1955 model, and looks to be painted in the Mist-Green that these machines came in originally. As the photos show, this bike comes with a plunger-style rear suspension, and plenty of rust and grime.

According to Bonhams, “The machine’s mechanical condition is unknown. Offered for restoration, the machine displays a total of 38,947 miles on the odometer and sold strictly as viewed.” The auctioneers expect a price in the $1,100-$1,600 USD range.

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