There’s a first time for everything they say. And to prove it, last Thursday, I took photographs of a motorcycle, parked in a field as the sun set. And why? Well, it just caught my eye – we don’t see many older motor bikes these days and this one just seemed to have that special something, and to be in an unexpected spot, that deserved a little attention.
I admit to never having been a motor bike fan, though MotoGP can be an exciting watch. I blame too many stories of people coming home with broken and missing limbs (or worse).
This bike though seemed to be a bit special, somehow. The appearance and stance, the balloon tyres, the full colour and the obvious age marked it as something a bit different from the regular Japanese, German or British bikes we see, and it seemed to deserve some attention. Basic investigation showed it to be 1957 registered Sunbeam S7.
The Sunbeam motorbike company, officially Sunbeam Cycles Ltd, was founded in Wolverhampton in 1887 and although formally unrelated to Sunbeam cars, was founded by the same entrepreneur, John Marston. Marston allowed the businesses to go their separate ways – Sunbeam Cycles ended up as part of the BSA conglomerate, owner of many British motorbike brands, and Sunbeam cars was eventually absorbed into the Rootes Group, through the acquisition of Sunbeam-Talbot-Darracq. In all, the Sunbeam name was used on bikes, motorbikes, cars, buses and trucks, Grand Prix cars and aero-engines, in what I believe is an uniquely wide range.
The S7 and related S8 were first introduced in 1948 and were openly based on the design of the wartime BMW R75, which featured shaft drive, and on versions with a sidecar, a differential and a driven third wheel. Is that still a motorbike, I wonder? Your call, but its ability on rough ground was unmatched by any other motorbike.
The design came to Sunbeam, based in Redditch in the English Midlands, as war reparations and the engineering was developed further. This was not a direct copy, but did retain some typical BMW features including the shaft drive. Sunbeam used a parallel twin, four stroke, overhead cam engine, rather than the flat twin familiar on the BMW, reportedly so it didn’t look German. One suspects that commonality with other BSA brands and compatibility with manufacturing equipment and expertise also contributed to that decision.
Sunbeam had various technical issues in getting satisfactory performance out of the S7 – the power had to be reined in to prevent transmission damage and the engine mountings extensively adapted to handle the vibrations.
There was another related model, known as the S8 also built – this was shorn of some of the expensive features of the S7, and intended to a more sports, less touring oriented product. Both versions lasted until 1956 when the Sunbeam brand was switched to scooters, with the BSA Sunbeam being a badge engineered Triumph scooter, until it was closed in 1964.
And why we were in a field at sunset? To watch the lighting of one the 3000 Platinum Jubilee beacons lit across the UK last Thursday evening.
And riding a motorbike? I once rode pillion in Mumbai; that was more than enough, thank you.
Ha! as to your last point – I rode many thousands of kilometers all around India in 2008 on a Royal Enfield Bullet and not only survived it, but loved it. You just need to be able to understand the local attitude to traffic “rules” and go with the flow. Learning to ride in Italy definitely helped!
As to the Sunbeam – lovely looking bike, especially in that color!
I do remember my father, many years ago, telling me about the Sunbeam motorbikes and saying that the rear cylinder used to over-heat.
He used to ride many bikes in his day and had tales on most.
A classic tale of how to copy a BMW and foul it up ! An in-line engine so that it didn’t look too German, and the engine had to be de-tuned so that it didn’t break the transmission – which wasn’t properly copied.
Meanwhile the small DKW two-stroke motorcycle was copied exactly by BSA and was very successful…
Remarkable that these Sunbeams still attract so much love.
Dear Uncle, you have to understand that copying the BMW would have been far too easy – just not the British way!
Rumor has it that the first prototypes of the S7 incorporated stronger transmissions and extra ducted cooling to the rear cylinder, but this made them far too fast, reliable and “German”. A request was therefore made from the highest level of the Ministry Of Production to Sunbeam to make a product with more “character”, or be denied scarce raw materials in the post war period.
In this Sunbeam were very successful, coincidentally ensuring the survival of the spare parts industry as well as dealer service departments. Owners were also spared the boredom of having nothing to do in their free time – having to repair their bikes meant they had less time to spend drinking or in other forms of debauchery.
This policy proved so successful that it was extended not only to the rest of the British motorcycle industry, but to the car industry too, as described in the book by L.J.K Setfire, “Excrement Was Expected”.
Pretty sad: copy the BMW and leave out the single most important feature, the boxer twin. It was inherently balanced, both cylinders got equal cooling, and it had a very low center of gravity. Not sad; stupid, actually. No wonder the British motorcycle industry died.
The Soviets didn’t mess with success when they copied a pre-war BMW motorcycle, and the resulting Ural sidecar motorcycles are still in production today, with many accumulated evolutionary changes but still with a boxer twin. Quite a contrast to the history of the Sunbeam motorcycle.
That’s a bit too easy. The Sunbeam was a dead end (to me it is a gorgeous machine) but there were many more successful years of Triumph and BSA motorcycles to come. Lack of investment, crap management and sloppy manufacturing quality were more likely the cause of the death of the British motorcycle industry.
I wasn’t suggesting that this Sunbeam was the actual cause of the death of the British industry, just emblematic.
In retrospect, it showed the first indications of the rot that was to become endemic in the British motorcycle industry. These bikes were followed by AMC (Matchless, AJS, Norton, and a couple of Villiers powered bikes) letting their lines slowly rot on the vine, leading to their extinction in 1965 – except for Norton which was picked up to form Norton-Villiers.
The balloon tires and general shape look very Harley-Davidson, perhaps Sunbeam should have kept the flat twin and built something more like the Harley Davidson XA. Rival Velocette seemed to have no problem installing BMW style flat twins in the LE, Valiant and Viceroy.
Were Sunbeam household appliances related? Sunbeam shaft drive bikes had a rep they corner well in one direction but stand up under power the other way.
It’s amazing how narrow vintage bikes could be. Outside of the handlebars, this one is barely wider than its headlight.
What a beauty .
In 1976 I was riding my 1937 Harley-Davidson KnuckleHead around Guatemala and a guy told me he had an old Moto he knew I’d want so I rode to his shop and there was one of these in white paint, all original and in V.G.C. .
Sadly I didn’t have the $250 and already had pissed off the wife by buying the Harley…
I know many love to hate British vehicles but they were generally designed to last in really rough environments (the colonies) , the failure was to make any serious effort in quality control in the initial manufacture .
There are quite a few of us who took the time to take some old British crock completely apart then assemble it to the proper specifications, they then ran far better, leaked less oil and were as reliable as anything else at the time .
-Nate
-Nate
I’m old and British – I wish someone would reassemble me so that everything worked better
I hear you on the latter point. For 22 years I had a 1969 Triumph Bonneville cafe racer that, for reliability, I’d put up against any single cam Honda CB750 made.
Don’t ask what I went through to get that Honda reliability, however.
Well Buck ;
I’m old and American and I’d like that too =8-) .
Flesh Mechanics do indeed exist but they’re nothing I want to mess with .
Syke ;
I already know how you reached Honda like reliability, it’s called “blueprinting” and almost no one understands what it means not how to do ot .
There’s a reason I drove a junkyard Nash Metropolitan FHD to Canada and back, it looked bed and the Canadian border guard jerkhoff didn’t believe I’d come that far in that car but why not ? =8-) .
-Nate
In retrospect, the first indication that the British motorcycle industry had started on the long road to failure, complete bankruptcy, and eventual rebirth (in Triumph – and Norton continues to try and hang on, going from failure to failure, will somebody please let it finally die one of these days?).
Given the impressive specs of the S7 on paper, the failure in performance was appalling. I too have heard that the rear cylinder tended to overheat, the differential was a worm drive that was completely under specced for the drivetrain, unimpressive handling, and a legion of other faults that would have been legendary if the motorcycle had actually sold in any numbers.
I am envious, however. You’ve at last gotten to see one in the metal. I don’t believe I ever have, despite having lived at vintage British motorcycle shows over the past four decades.
The Sunbeam S7 engine would go on to influence Walter Hassan during the development of the Coventry Climax FW engine, a descendant of which would become the Hillman Imp engine.
I do wonder if it also influenced Ricardo engineering during the development of the Triumph-Saab Slant-Four engine, with the 16-valve design itself coming from advice by Coventry Climax engineers.
https://www.imps4ever.info/tech/cov_clim.html