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Reference: BSA Bantam D1

Roy Poynting, pics by Terry Joslin
March 11, 2013
1951 BSA D1 Bantam 125cc

I’m always wary when people have dogmatic opinions about motorcycles, and that applies whether they are unreasonably critical of other riders’ mounts, or unquestioningly convinced that the sun shines out of their chosen model’s exhaust pipe. So when someone informs me that BSA Bantams are the best things since sliced bread, I have to ask when they last rode one, and 99 times out of 100, they either haven’t been astride one for decades, or they’ve never ridden one at all. Well, I’ve owned and ridden Bantams of various types – from a 125cc D1 that never ran properly (being given it for nothing should have alerted my suspicions…) to a 175cc D10 that needed to be driven harder than seemed decent for 40-year-old machinery – and their only relationship to sliced bread was that they were mass produced and cheap.

1951 BSA D1 Bantam 125ccHowever, I’m being hard headed and just thinking about the performance (or lack of it) and I’ll return to that in a moment. But what first strikes people about all Bantams is their attractive appearance, and that especially applies to the first in the line, the D1 that was launched in 1948. It has the essential cuteness of a small motorcycle that’s totally devoid of styling frills, but which has everything neatly in proportion. Just about everybody – even ladies with absolutely no interest in motorcycling – approaches one with the sentimental ‘oohs and ahs’ of a grandmother greeting a new baby.

However, while newborn babies are cute (so I’m told) they are not very useful, and I’m convinced that if they were honest, most Bantam restorers would feel the same about the result of their efforts. They start off a restoration project basking in the rosy glow of long ago, when any motorised cycle seemed miraculous, but complete their work to find that rose-tinted memories totally fail to keep them out of the path of white van drivers on a tight schedule. Oh sure, there are a few brave souls and masochists who still use their D1 on a daily basis, or regularly take one on a touring holiday in the Andes (‘…where it needed absolutely no attention apart from two engine rebuilds and new frame!’). But there are considerably more who make a single outing on their Bantam and then keep it for show.

That might alienate or discourage Bantamophiles trying to recreate the machine they owned in their youth, but it won’t upset owner Mike Tottey, who only restored his D1 Bantam because it was what became available at just the time he was looking for a new project. Before he took the Bantam in hand (cue for a joke about a bird in the hand being worth two in the bushes) it had been sculling round the local VMCC section for quite a while, and its previous owner – Alex Sheppard – had already started restoring it, and had collected quite a few parts like the handlebars and the neat little carrier.

1951 BSA D1 Bantam 125ccMike’s work therefore centred on the cosmetic and electrical aspects, and creditably, he did most of the work himself. He made his own wiring harness, and sprayed the paintwork (even the wheel rims were painted on early Bantams) in the correct Mist Green cellulose from T&G, applying the petrol tank’s coach lining with tape. Hampshire Electro Plating did what little chroming was needed. Some items are specific to certain Bantam models, but that was no obstacle to Hampshireman Mike, who is a skilled self-taught engineer. The rear number plate, for example, he made by beating sheet steel over an appropriately shaped wooden former.

The Bantam had been off the road so long that its details had never been put onto Swansea’s computer, but it fortunately came with some old MoT and insurance certificates, so its original registration was simply reinstated. The HCR 18 plate was issued in Portsmouth, so the machine has probably never strayed too far, but it appears to have been well used during its working life, as its odometer shows nearly 23,000 miles.

As it happens, Mike Tottey could well have become the owner of a similar Bantam a long time ago. “I wanted a D1 for my first bike,” he tells me, “and I ordered a new one from racer and dealer Bob Foster. Unfortunately it simply didn’t arrive in those days of ‘export or die’, so I bought a second-hand 250cc BSA C11 instead.” More than half a century later, 1951 BSA D1 Bantam 125ccMike’s restoration enabled him to have his first ride on the model he’d been unable to obtain, and he immediately experienced exactly my concerns about its lack of power, and the limitations of its three-speed gearbox. “It felt as if it was geared too high,” he says, “so I went back to Alex – who’d restored the engine and gearbox before I took over – and he assured me that everything was as it should be.”

I’d go further than that, because this D1 is rather better than others I’ve tried, being the De Luxe version with rear suspension (wow!), and decent electrics. Now, it’s a knee-jerk reaction to knock anything made by Joe Lucas (aka the Prince of Darkness) but let me tell you, if you want an early 125cc Bantam, try to get one with the Lucas battery set that was an extra-cost option between 1950 and 1953. Perhaps it wasn’t anything special, but it was a distinct improvement on the original Wipac (Wico-Pacy Ltd) set-up with direct lighting, and less troublesome than the Wipac battery system that was used subsequently.

You see, all of the Wipac-equipped Bantams right up to 1963 relied on flywheel magnetos, just like most Villiers engines. But while the Villiers set-up was generally well constructed, the BSA/Wipac system was obviously value-engineered with a much smaller flywheel, which meant that the magnets and coil were barely big enough to give a hefty spark. Waterproofing wasn’t brilliant either, so the coils suffered from internal corrosion if allowed to get damp. To make matters worse, the crankshaft extension that carried the ignition points outboard of the flywheel was rather frail, so it could whip about with predictable consequences for the points’ gap and timing.

1951 BSA D1 Bantam 125ccThe earlier systems also relied on direct electricity from the Wipac Geni-Mag (generator-magneto) to power the lights. This meant that the output depended on your speed, so if you slowed down because of poor visibility at night, your headlamp dimmed and you still couldn’t see! The optional Lucas system, however, used the flywheel generator’s output to charge a battery, which then powered the lights and an HT coil, just as on a proper grown up motorcycle. True, the points were still on the end of the shaft, but a battery/coil set up is much better able to cope with timing variations than an energy transfer one.

Despite this, many found the cheaper Wipac system adequate when it was new, and to put the other side of the argument, the Geni-Mag allowed 1950s riders to do without expensive and potentially troublesome batteries and rectifiers. Those problems don’t apply today, and the argument has swung back in Lucas’s favour. Batteries are cheap and reliable – although Mike has not yet found a Bantam-sized one with a period finish – and modern solid-state rectifiers are cheap, rugged and small enough to be hidden away, while the massive selenium metal plate job can be left on display by concours-orientated restorers.

1951 BSA Bantam D1 125ccLucas-electric Bantams are instantly recognisable by a combined lighting and ignition switch on the headlamp. Since these were only featured during three years nearly six decades ago, they are understandably rare, but Mike was delighted to find that specialist dealer Malcolm Leech could supply one from stock. Wipac-equipped Bantams didn’t need an ignition switch, of course, and while the actual lighting switch on early versions was located in the headlamp, it was bizarrely controlled by cable from a handlebar lever – surely an unnecessarily expensive and complicated system for an economy machine.

The upshot of all this is that a tickle of the carburettor and closure of the strangler built into the wire gauze air filter, followed by a turn of the key and a couple of prods on the stubby kick-start lever, has Mike’s little two-stroke, popping merrily away. The clutch is light, and slight pressure on the gear lever (one down, two up) soundlessly engages first gear. Using enough revs to avoid an embarrassing stall, I let out the clutch and I’m away. Admittedly there wasn’t much chance of wheel spin – even in the downpour in which he’s kindly letting me ride his new creation – but the initial acceleration is surprisingly sprightly.

BSA Bantam D1 125ccThe key word is initial, unfortunately, because the reason that the take-up is so quick is that the first gear ratio is extremely high – in fact it’s comparable to that found on contemporary off-road competition machines – so the engine almost immediately gets to peak revs. Going for maximum acceleration on a similar D1 De Luxe in 1950, Motor Cycling magazine’s tester could only get to 10mph in first gear before having to change up. There is then a big jump to the second ratio, and premature changes leave the rider becalmed with the engine running too slowly to produce meaningful power. The same thing happens when changing from second to top, and if faced with an incline the rider might as well accept the need to keep the engine screaming away at 25mph in second, rather than get bogged down in top.

'I seem to be labouring this point (rather like a Bantam trying to get up a long hill) but what a difference it would have made if BSA had provided a four-speed gearbox in 1948, instead of waiting another 18 years!'

I seem to be labouring this point (rather like a Bantam trying to get up a long hill) but what a difference it would have made if BSA had provided a four-speed gearbox in 1948, instead of waiting another 18 years! Interestingly, the 125cc Villiers 10D engine, which was introduced at the same time as the D1 Bantam, initially featured very similar gear ratios. After only two years, however, Villiers reduced the first and second gear ratios by over 20 per cent, making 10D-powered commuters from the likes of James and Francis-Barnett much easier to ride.

They didn’t look so good, though, and it’s ironic that BSA’s most successful model – 400 a week were produced at one time, with the total production exceeding a third of a million – wasn’t BSA’s design at all. As is well-known, the designs presented to BSA (and several other manufacturers) as war reparations, meant that the D1 was almost a mirror-image copy of the pre-WWII DKW RT125, And perhaps BSA was lucky that the urgent need to get a cheap and cheerful commuter onto the market prevented the temptation to make too many changes.

1951 BSA D1 125cc BantamTelescopic forks replaced girders, of course, and as was common at the time that led to a deeply valanced mudguard mounted under the lower fork yoke. This seldom aids the appearance, but the Bantam’s springing is soft enough that the wheel sits neatly under its guard once the machine is off its rather flimsy centre stand. And the semi-fishtail silencer is a feature that’s attractive and instantly recognisable. Since it was presumably designed to avoid the rider’s heel when kick-starting, it could also be described as functional, but it was apparently prone to being clogged by the combustion products of contemporary oils, and was eventually changed to a tubular design that could be dismantled.

For a small machine, comfort isn’t at all bad. The saddle is low – which suited ladies and teenagers – and BSA compensated by lowering the footrests, so things aren’t too cramped. The low footrests are easily grounded on corners, of course, but that wasn’t a problem for most users, and was a distinct attraction for eager youths. I well remember enviously watching Post Office Telegraph Boys deliberately striking sparks off their footrests as they pursued their dreams of becoming another Geoff Duke. Even the plunger suspension seems more effective than usual, presumably because the machine is so light that the springs could be made soft enough to actually respond to the rider’s weight.

But would you be happy venturing onto the modern traffic maelstrom on a motorcycle that takes half a minute after leaving an urban 30mph limit to get to a cruising speed in the 40s? The two-legged Bantam is an appealing little bird that is more frequently exhibited at fowl-fanciers conventions than kept to produce eggs for sale. Similarly, while the Birmingham-made two-wheeled version is undeniably attractive, I’m afraid you’ll see an awful lot more of them at static shows than actually being used on the road. bike

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