BSA'S STAR
Outstanding early twin
The introduction of Triumph’s groundbreaking Speed Twin in 1938 left the rest of the major British motorcycle manufacturers playing catch up. BSA’s answer to Triumph’s new parallel twin was the A7… but not the bike which Bert Hopwood designed, sibling to the A10. No, the original A7 was quite a different machine from its muchloved descendant.
BSA came up with their own take on the vertical twin format with a long-stroke iron head engine, the basic design of which is generally credited to Val Page. However, Edward Turner, Herbert Perkins and David Munro are all also known to have had input into the design. With designers of this pedigree you would have expected BSA to have got it right first time. Design work started in 1939 which, obviously, meant the A7’s launch couldn’t happen until 1946. Then there were a couple of problems which possibly contributed to the bike’s short production run; in 1950 the A10 and subsequently the revised A7 were introduced.
The original A7 was an ohv, iron head vertical twin with a single camshaft and a four-speed gearbox which was bolted to the rear of the engine. The crankshaft assembly was unusual in that it comprised three main parts, yet despite its complexity the design was intended to be easily rebuilt by the home mechanic. It was, however, very quickly replaced by a re-designed single-piece unit, possibly because of the manufacturing cost of the original; the replacement version being interchangeable with the first. A 62mm by 82mm bore and stroke gave a capacity of 495cc. Compression ratio was 7:1 and a single carb was used. Output was claimed to be 26bhp.
The engine and gearbox were housed in a rigid frame with telescopic forks. The wheels were interchangeable, which necessitated the use of a wide fork leg spacing at the front end. Another unusual aspect of the initial A7 was that the centrestand comprised of a single leg which retracted into the frame’s tubing, and which was operated by a ratchet mechanism. Reports suggest that the ratchet used to fail on occasion and the centrestand would descend while the bike was in use. In reality this doesn’t seem too likely as the stand is retained by a very powerful spring. A previous owner of the featured machine did describe using the stand as akin to trying to lift yourself up by your shoe laces, however! It was possibly not the best of designs and was soon discarded.
Another ‘issue’ and perhaps the A7’s biggest design flaw was the use of ‘oil mist’ lubrication for the top end of the engine. This resulted in a shortage of lube and caused excessive wear to the cams. It was also important that the correct primary chaincase oil level was maintained as low oil resulted in damage to the primary chain and tensioner, while too high an oil level resulted in clutch slip.
Just over 1700 of these bikes were made with around half being exported, so sixty years later they aren’t among the most common BSAs around. The selling price new was £177.16s including tax.
In common with usual BSA practice, the engines and frames do not have matching numbers. They were just picked from stock for the assembly line. Dispatch records still exist and they show a number of missing engine numbers for the early bikes – this might suggest that BSA experienced some sort of problems with these first engines.
The featured bike is the earliest one known to still exist and was the 57th A7 built. Nearly seven decades after it was built the A7 retains most of its interesting history. The bike was originally dispatched from Armoury Road on the 7th of February 1947 to the dealers Knighton Delve of Barnstable ( just up the road from RCHQ, in fact). It next appeared in Wooldridges’ BSA Motorcycles of Launceston ( just down the road from RCHQ…) in 1949, from where it was purchased and used as a daily commuter to travel from Port Isaac to Wadebridge. In 1953 misfortune overtook the A7 and it was involved in an accident at
Boscastle, perhaps because it couldn’t quite stop quickly enough. Thereafter it was placed in a fish cellar – really – in Port Gaverne until being purchased in 1981 and then eventually used in a part-exchange deal for a newer model A7 at Camelford Bike Bits.
In 1988, Peter Ball of Cheshire heard of the bike and bought it unseen. When he went to collect it from Exeter he was somewhat shocked by the state it was in. The years in the fish cellar had been – as you might expect – unkind to the bike, and Peter described it as looking as if it had come out of a canal. The restoration was not going to be an easy one…
Apart from a heavily worn camshaft, the engine was surprisingly in pretty good condition. Repairs were needed for the inner chaincase and some broken fins on the barrel. Other than that, it was the usual case of new rings, bearings and cam followers. The camshaft however was a more difficult proposition and a new one took quite some time to find. The gearbox was rebuilt requiring only new bearings, but the rest of the bike was to prove much more of a problem.
Both the petrol and oil tanks were totally shot, and replacements were impossible to find. Pete acquired a 1948 tank, had the top cut out of it and the same section from the original tank, which contained the speedo, was welded into the later component. The modified petrol tank was then re-finished as per the original. The oil tank was just replaced by a newer one from a later model; the replacement had a drain plug which the early one was missing but that was the only difference.
Mudguards were stripped, holes welded, the surface restored and then stove enamelled. The forks and interchangeable wheel hubs were another problem. Presumably, when the bike had been reassembled after its accident, the wrong ones had been used, so replacement hubs of the correct type were sourced and laced into new rims. The forks were more challenging and it took Peter a couple of years to find the
correct ones. With them installed, a magneto rebuild and a new carb fitted he was well on his way to completing his project.
It had always been Pete’s intention to make the A7 as standard and close to original as possible, so he even fitted block tread tyres to both wheels. This quest for originality proved to be an expensive one. Even in those days a replacement headlamp of the correct type cost him a staggering £150 – and it still needed renovating!
After all that work, sourcing and modifying parts to complete the restoration to such a high standard, Pete then made what seems like a surprising decision: to sell the BSA. He parted with it in 1998; it then moved to Portsmouth where it spent the next 18 years of its life until recently was advertised for sale once again, this time on eBay. The winning bidder, Albert, is the current Proud Owner of the A7, and he had very little work to do to get the machine roadworthy once more.
A steering problem was traced to the blocktreaded front tyre, so that was replaced by an Avon Speedmaster, and the magneto failed, so work was needed to bring that back to life. Concerned about the poor oil supply to the top of the engine and the camshaft, Albert takes the time to remove the rocker caps and just squirt some oil into the rockerbox before each ride. As some 20 years have now passed since its restoration, the bike’s chrome has suffered a little. This may not actually be a bad thing; it adds somewhat to the character of the machine and acts as a reminder of its age.
When the A7 was first introduced in 1946, an early road test in Motor Cycling praised the new twin for its mechanical quietness, exceptional roadholding and its ‘novel and excellent’ centre stand (which directly contradicts later reports). Top speed was quoted at around 80mph. The tester described the bike as a very pleasant model that could be ridden as slowly as 7mph in top gear without snatching, and yet would accelerate cleanly from that speed without the need to make a downward gearchange. When, many years later, another example was compared to the 500 twins of the time, the tester found the engine somewhat quieter than a similar Triumph unit. The BSA’s outboard front brake was pretty much useless, but the forks were described as ‘outstanding.’
So what’s it like in 2016? What does new owner Albert think of his A7? Well, Albert has wanted one of these early A7s for a long while, so to actually own one is a dream come true for him. His previous bike had been a B31 and he admits that he expected the A7 to be pretty much like a more powerful version of the 350 single. In reality, the twin feels a lot heavier than he had imagined it would. The brakes are not as good as the B31 and he also describes the front one as being abysmal. The rear brake is just about acceptable – which
means that when riding he needs to maintain a high level of anticipation. Albert hopes that new linings will improve the braking… before a repeat of its 1953 mishap re-occurs!
Starting is reliable but the motor does take a little while to settle down to steady running; Albert believes that a little more fiddling with settings will improve this. First gear can be engaged without the customary clonk and finding neutral is easy, but when rolling the gearbox can be clunky and may need further attention. The clutch is excellent, light and slip-free.
Despite its shortcomings, Albert finds the A7 a joy to ride and says it’s easy to forget that the bike has no rear suspension, the sprung seat soaks up the bumps so well. The front forks also come in for praise, performing much better than their age would suggest. On top of this, the bike’s low centre of gravity inspires confidence in the ride, and Albert reports that the exhaust burble in top gear is a joy to his ears. That has to be the icing on the cake – Albert seems more than satisfied with the bike’s roadgoing performance.
But what about the centrestand, you may ask? Does it deserve its poor reputation? Or was the original roadtester correct? Albert’s assessment is that the stand is great! Instead of having to heave a heavy bike onto its stand as people expect, he just stops the bike, presses down on the stand’s lever and hops off the bike. Spectators are truly amazed. Mind you, that poor reputation means that Albert can’t quite bring himself to trust it totally, yet, but it is gaining his confidence.
So what next for this particular A7? As mentioned earlier, Albert had coveted such a machine since his youth: its visual simplicity made a massive impression on him. For many years, however, the rarity of the model and its subsequent premium price tag meant he confined his admiration to the ‘if only’ category. Then a very good friend and motorcyclist died, which nudged Albert into reappraising his priorities. So with a ‘life is too short’ attitude, he began his search which ended so successfully.
Thanks to Peter Ball’s patience and dedication, the A7 was reborn when it was half a century old. Now Albert, a skilled engineer who loves almost everything about it, has taken on the responsibility of looking after it. Such is Albert’s confidence in his ability to solve its few flaws that he has committed to riding the BSA to the Isle of Man for the 2017 festival to celebrate its 70th birthday. The A7 has already been restored to regular use, and it’s the only bike which Albert owns. He aims to use the A7 just as it was originally intended when it first rolled out of the Small Heath factory in 1947. Who would bet against him? Not me!