BSA GOLDEN FLASH
What was once commonplace is now pretty rare. Frank Westworth muses on the plunger Flash, one of his forgotten favourites
What was once commonplace is now pretty rare. Frank Westworth muses on the plunger Flash, one of his forgotten favourites
Histories are marvellous things. When a personal history overlaps with actual real history, it can be even more marvellous, not least because comparing personal memories of what happened with official versions of what actually happened can be seriously entertaining. And I’m talking only about motorcycle history … and motorcycling history, which may or may not be the same thing.
Take my own formative riding years: the very end of the 1960s and the early 1970s. It was a time of considerable irreverence and sudden and unexpected mobilities, both personal and social. It was of course a golden age … if only for me because I lived then and very much of the remainder of my life has been stimulated by those times. And bikes were central to that. As were music, politics, the counter-culture and much more. But bikes held the rest together because of the physical mobility they provided, as well as being a fascination which has lasted from then until now. An amusing thought for the first day of the new year – which is when I’m writing this: January 1, 2019.
What has this got to do with the Golden Flash which hopefully RC Smudgocolor™ has revealed in glorious black somewhere nearby? Well, it’s minor admission time. I always wanted a plunger Flash. Several times I tried to buy one and every time I failed. I have now given up. They were once so common that folk gave them away for free – two of my 1970s pals were given buckshee Flashes, and both converted them into horrible Easy Rider wannabee horror stories, mainly by fitting insanely overlength fork stanchions (available through the ads in Motorcycle Mechanics magazine at one point), which made them terrifying to ride. And down through the (how many!) years I’ve ridden quite a few, but none was for sale at a price I could pay. I told myself it was A Sign, and pretended to give up.
I did however own several swinging arm BSA non-unit twins, and even built a plunger Flash power unit into an A10 frame I had laying around, added Ariel forks, a Norton front wheel and an A65 fuel tank, a café racer twinseat and a lot of rattlecan blue paint and thus added to the world’s grim total of poorly customised BSA twins. That one was a lot of fun, although it twice tried to murder me … but it still was not entirely a plunger Flash.
Fast forward until sometime last year. I’d wandered north with A Plan, a plan which involved spending a fun day aboard either a Nimbus or a Zündapp – a madcap four or a truly unusual twin, what a choice! Of course, when I landed at Venture Classics’ weary riders’ tea-room it was lashing down. Hammering down. Tempesting. Chris and I stared at the skies. They were dark in every direction. The Zündapp and Nimbus sat glittering in the shimmer of falling raindrops. I looked at him; he shrugged. ‘ They need a clean anyway…’ he offered, gently.
Time for further exploration of only possibly poisonous coffee and some discussion of politics. We do this a lot, especially when the skies are doing their best to drown us. Then there was the innocent stroll around the showrooms, as always, and as always I lamented the lack of ‘real’ bikes, like lightweight Norton twins and … plunger
Flashes. Chris stopped. I wondered whether his coffee had taken its final heart-stopping revenge. But not. ‘Funny you should say that,’ he said, thoughtfully, and led me off to a less glamorous part of the grand sheds, where he revealed … you’ve guessed, haven’t you?
One of the very many most excellent features of BSA’s only slightly unglamorous plunger Flash – especially the black, nongolden variety – is that it’s weatherproof. All that happens when one gets ridden in vile weather is that it gets wet and dirty – there is very little shiny chrome or polished alloy to suffer. BSA built their sidecar-hauling twins in the recessive years of the 1950s; chrome was scarce. And this bike was not a conkers bonkers show queen, either. It looked exactly like it was: a working machine more than happy to get a little wet. I looked at it, then at the glittering Zündapp nearby, and smiled. Could I? Of course I could.
But first, while I struggle back into my only slightly soaking gear (200+ miles from RCHQ Bude, mostly in a deluge, is a trial even for the best bike kit), here’s a little history.
BSA’s parallel twin was of course inspired by and intended to compete with Triumph’s Speed Twin. The latter was – as you know – famously designed by Edward Turner. What you may not know is that the same Mr Turner worked for a while on the design of BSA twins while employed by that company for a couple of years from 1942. If you’re feeling enthusiastically anorak, Signs Of Turner can be found here and there in the early 500 twin engine, the A7, including Triumph-style screw-in rocker adjustment covers in the rocker boxes. And the original engine had two rocker boxes, like the Triumph, but unlike the A10. The bike seen here is later, and uses a redeveloped engine, credit for which is usually given to Bert Hopwood, although a redesign of the earlier engine was already under way when he joined BSA in 1949.
The development history of the pre-unit BSA twin engines would fill an article all on its own, but Hopwood’s systematic and neat work on the original engine was excellent, despite sticking pretty closely to the original basic idea. Like Turner’s Triumph, the BSA engine is a 360° parallel twin with a pair of overhead valves doing the gassy stuff up top. Unlike the Triumph, which has a pair of camshafts, one for inlet, the other for exhaust, the BSA uses a single shaft to perform both duties, an arrangement which is familiar to owners of Hopwood’s Norton twins. In the BSA engine, the camshaft lives behind the cylinders, whereas on the Norton it’s in front. Given that part of the reasoning behind the single cam was to remove potential cooling problems caused by the Triumph’s external exhaust pushrod tube, the Norton cam placement seems a little perverse. However, the BSA block has the pushrod tunnel cast-in at the back, with careful thought given to air flows.
The head is very neat too, although generations of BSA owners have cursed the one-piece rocker box and its fiddly pushrod location.
BSA wanted their engine to be
mechanically quiet, so while the camshaft is driven by gears, the dynamo is spun into charging the battery by a short and small chain, running in its own compartment and lubed by grease. This works well, although the costing cannot have been improved by the fact that the engine has two timing covers.
Inside is where the horror story lives. At least … it’s a horror story if you believe in such things. Your humble scribe has ridden far too many miles on far too many limply maintained Beezers to really worry about the timing side main bearing, but has long accepted that other views are both available and popular. The problem? The horror? As was common at the time, the early – and indeed all – versions of the BSA twin rely on a long bush to both support the timing side end of the crankshaft and to supply oil to the big ends. The horror story goes that the bearing can wear prematurely, and as clearance between shaft and bush increases, so the oil supply and pressure to the big ends fall. The fix is available, of course, should an owner wish it.
The other end of the crank is supported by a hefty roller bearing (replacing a ball race in the earlier engines) which is apparently bombproof. So far, so well-known BSA. Look at the engine from the primary drive side – the left. Observe how the chaincase appears shorter than usual for a pre-unit engine. This is because although the design is indeed nonunit – in that the crankcase and gearbox shell are entirely separate castings – the gearbox is bolted to the rear of the crankcase. As well as being commendably compact, this also does away with the primitive pre-unit method of adjusting the chains; none of that fiddling with oily bolts to slacken the gearbox in the engine plates so it can be pushed backwards to tighten the primary chain … while at the same time slackening the main chain, which in turn demands grubbing about with more worn out and filthy bolts to yank the rear wheel backwards to tension the main chain again… Why Norton persisted with this until the timely introduction of the Mk3 Commando I have no idea.
Happily, the plunger twins bask in the benefit of a slipper tensioner for the primary chain. And the reason they’re called plunger twins is because of the oddly-named rear suspension devices, colloquially known as plungers. Why? I have no idea. They barely move, let along plunge.
Riding kit on, there’s a break in the deluge. Can I see a hint of sunshine? No. Time go and get the previously shiny clean machine filthy, then. I smile at Mr Proud Owner. He pulls an expression. It may have been intended as encouragement, but I’m unsure about that.
Wheeling the Beezer around is an eyeopener after performing the same stunt with my own more modern machine. It’s so … light. And compact. And indeed wieldy. The saddle height is refreshingly low, too, as I discover as I fling the leg over. For added delight I would throw away the pillion saddle – I never carry a passenger – but it doesn’t get in the way too much. Set the controls (no Pink Floyd jokes, please), which is easy as the ignition timing is handled by an automatic device inside the engine’s timing chest, so all it needs is a little choking. Except when hot, as I discovered later. Ahem.
Tickle the carb – a somewhat aftermarket Concentric, and no harm in that – and apply hoof to lever. Two kicks. Lovely. Recall that as I don’t know the bike at all I should probably check that the oil’s returning, then think dismissive things and just sit for a while, listening to the rumble and letting the stonecold engine warm through enough for me to start easing back the choke and catching the revs with the throttle. The engine sounds delicious. It seems unlikely that these are the original 1952 silencers, but they’re not loud, and they do boom mellifluously. That’s a great word, very descriptive of older BSA twins. Nothing harsh at all, hardly any rasp, which reveals that the timing is spot-on and that the silencers are indeed possessed of baffles.
I love engines. Really do. Despite my advanced age I have never grown out of the sense of wonder that such a mechanical thing, with so many parts, can actually work at all. And this particular lump is a treat. Like almost all iron-head engines, the A10 is very quiet mechanically, with no piston noise at all and precious little audible indication that the valvegear is actually doing anything. It’s also l remarkably k bl smooth. hV Very nice. i Maybe Mb BSA’s determination to avoid the Triumph twin’s timing gear rattles was a good idea. In the time it’s taken me to perch my helmet on my head and struggle into the (very wet) gloves, the engine has already warmed up sufficiently to permit the choke to be closed, leaving an almost steady tickover. It’ll be interesting to see how well mannered it is after a splash’n’dash through the rains.
Light clutch. Some people are unflattering about BSA’s clutches. I’m not one of them. This example is light, well adjusted too, and first gear slips in with hardly any effort and very little noise. No clash’n’grab here, happily. The lever on these boxes is short, there’s not a huge amount of travel, and the entire operation feels surprisingly modern. All of this is good. Part of the reason behind the clutch’s civilised behaviour may have been that the clutch itself, despite living inside the primary chain’s oil bath, runs dry. This was achieved by fitting a cover over the clutch
drum, and for it to work well a rider should check that the level of oil inside the primary chaincase is correct. Too low and the chain suffers, along with the gearshift; too high and oil contaminates the clutch and the plates slip. If you come across either of these phenomena while negotiating for a purchase, bargain away. The fix is simple.
Time to operate everything and to get going. Nothing could be easier. This is a truly gentle, mellow machine to ride. I can’t say this often enough. I’ll offer a personal view here, and that is that far too much ‘classic’ emphasis is placed on sports machines, and not enough on the actual working motorcycles from back then. This is a prime example. While researching for this story, I spent time looking for plunger BSA twins for sale, and found remarkably few, probably because their owners love them and want to keep them, and because lots of them were ridden until they simply wore out. It’s also probable that they wore out before the great old bike price inflation. When I checked, there were a lot more Beezer sports bikes offered for sale too, which may tell us something. Or not, of course.
Traditionally, folk praise singles for being nimble, slim, flickable … things like that. Well, to be honest, this 650 twin is just about as capable in the flickability stakes as, say, a B31. According to BSA’s stats, its seat is an inch higher at a lofty 30”, while its dry weight is a tubby 408lb compared to the contemporary B31’s svelte 324lb. This may lead a chap to believe that the Flash is a lardy lump, but in fact it doesn’t ride like that at all. And its 8” front brake is an inch bigger than the single’s, so… erm… I’ll get back to the brakes in a little bit.
It’s always a minor entertainment when writing up riding impressions like these, not least because I try to offer comparisons with machines with which you, gentle reader, may be familiar. So I’ll reveal that compared to any modern machine of a similar capacity, the Flash feels very light, simple and agile. Comparing it to a modern machine of similar power output – 35bhp or so when new – is less simple, because there are a lot of much more modern models which are as agile, although few are as simple. Comparing it to its contemporaries is easier. It’s as pleasant to ride as a Triumph Thunderbird, and the Beezer’s plunger back end is easier to live with than a sprung hub. That said, does that really matter unless you’re planning on using the bike as high-miles, everyday transport?
Where the Beezer really wins over the Triumph may not be a plus point from another rider’s perspective. The BSA is rather more relaxed. Set a speed and it will maintain it – within its performance limits, of course. A decent 650 Triumph, on the other hand, gives the impression that it wants to go faster. Which is why you saw relatively few Triumphs hauling family sidecars around, whereas the Flash was more commonly seen with said sidecar. The Beezer brakes better, its suspension bounce is better, and this rider prefers its handling and riding position. Ah… the brakes.
The brakes are fine, both of them. The front is the usual 8” sls drum operated by cable, and is in fact one of the better stoppers of the period. It is, for example, superior to both Triumph and AMC offerings, and about as good as the contemporary Norton. The rear is almost too fierce, which is probably not a bad thing except in the wet. I wondered whether this was deliberate, given the likelihood of the bike hauling a third wheel, and taking into consideration the roads of the day – which included wooden setts in several cities. But then I decided that I was being too clever and ignored myself. Good brakes, OK?
A Flash can be deceptively quick, too. The engine, frame, gear ratios and brakes all combine with a good riding position to encourage the longer ride, rather than the café sprint. Which is of course why BSA developed Super Rockets in later years to satisfy more sporting riders. I really enjoyed my time with the bike. I prefer black to the more common golden beige, and I actually enjoy the slightly odd behaviour of the rear suspension. It’s oddly involving, and I wondered whether the rear tyre actually affords more ride comfort than the plunger frame… Lighting and electrics are typical for the time. And… this is a great bike to ride whatever the weather. Very little brightwork to be tarnished by the deluge, which removes at least one psychological impediment to enjoying the less than sunny days we all know so well.
Downsides? Very few. The power train is very familiar and there are specialists who can upgrade it as much as you want, if you want. Me? I’d be happy with a bike like this, just as it is.
Thinking back to the reason that although BSA sold billions of plunger Flashes there appear to be very few around today, I suspect that it is because they are indeed an example of that unsung hero – a bike which just kept on working until it was entirely worn out. And while Early Classic Man was prepared to unload megadosh to rebuild that Rocket Gold Star… the Flash rider simply bought another cheap Flash to ride until it too wore out.
They’re great bikes. I have no idea why I’ve still never owned one…