This is a 1950 Sunbeam S7 Deluxe, it’s a fascinating motorcycle that owes its existence to WWII, BMW, and its designer Erling Poppe. The styling of the S7 was influenced by both German and American motorcycle design, with its sweeping fenders and balloon tires fitted front and back.
The S7 is powered by an innovative longitudinal inline-twin with a single overhead cam and a shaft drive system with power being transmitted to the rear wheel via a worm drive. The top speed of 70 mph was good for the era and the design of the bike has been winning it plaudits for generations.
Fast Facts – The Sunbeam S7 Deluxe
- The Sunbeam S7 Deluxe was the successor to the earlier Sunbeam S7 which had been released in 1946 with some of its design attributes borrowed from the BMW R75, which Sunbeam had gained the rights to as reparations after WWII.
- Rather than using the horizontal boxer twin engine design of the BMW (which had originally been pioneered by Douglas), Sunbeam opted to use an advanced new inline-twin design with an overhead cam.
- The design of the S7 was somewhat reminiscent of the German and American WWII motorcycles, like the R75 and the WLA, bit its unique engine set it apart.
- The S7 was succeeded by the S7 Deluxe in 1948 and the S8 would follow later with its skinner tires and fenders which completely changed the look of the bike.
The Sunbeam S7 Deluxe
The Sunbeam S7 Deluxe is a post-WWII British motorcycle that emerged as an improved version of its predecessor, the original Sunbeam S7. Launched in 1948, the S7 Deluxe aimed to address the shortcomings of the original model, in the hopes that it would boost the model’s flagging sales.
The Sunbeam S7 was considered a luxurious motorcycle by the standards of post-WWII Britain, it had front and rear suspension, large balloon tires, and ample fenders to ensure road grime and puddles didn’t get flicked up onto the rider or pillion.
The Sunbeam S7, first introduced in 1946, was a groundbreaking motorcycle in terms of design, however, it faced stiff competition from other British motorcycle manufacturers and the model had a few issues, such as a propensity for oil leaks and somewhat underwhelming performance.
In response to customer feedback and market demand, Sunbeam launched the S7 Deluxe to address these issues and provide an improved riding experience for its owners.
Some of the most notable changes and new features included:
- The S7 Deluxe’s 487cc overhead-valve (OHV) inline twin engine was modified to reduce oil leaks and improve reliability.
- The redesigned cylinder head and more efficient lubrication system contributed to smoother power delivery through the rev range, and the engine had new cylinder linings, and increased oil capacity.
- The S7 Deluxe featured revised gear ratios, which helped improve the motorcycle’s performance in terms of acceleration and hill climbing ability.
- The exhaust system was also redesigned to reduce heat and noise, improving the overall riding experience, and the frame was redesigned.
The 487cc engine is a unique inline-twin design with a single overhead cam, it’s an air-cooled motor with an alloy block and head, and it sends power back through a 4-speed transmission and a shaft drive to the rear wheel.
The Deluxe was powered by an improved version of the S7’s original inline-twin cylinder engine which had been designed by Erling Poppe as Sunbeam didn’t want to use the “German” horizontal twin made famous in the BMW motorcycles of the era.
The engine was advanced by the standards of the time, most motorcycles relied on either flathead or overhead valve designs, but the Sunbeam S7’s 487cc engine had a single overhead cam operating two valves per cylinder. The inline-layout was very space efficient, and power was sent back through a 4-speed gearbox and a shaft drive to the rear wheel.
With 24 bhp the S7 wasn’t earth-shatteringly powerful, but it was designed as a daily-rideable motorcycle not as a racer, and it’s built up a strong following in the years since its introduction. The 70 mph (112.6 km/h) was more than enough for most, and those who wanted more could buy a later Sunbeam S8 which had a top speed of 85 mph (137 km/h).
Interestingly, the British actor Robbie Coltrane who is perhaps best-known for portraying Hagrid in the Harry Potter series, had a Sunbeam S7 Deluxe that he loved dearly. You can read its story here if you’re interested.
The 1950 Sunbeam S7 Deluxe Shown Here
The motorcycle you see here is a 1950 Sunbeam S7 Deluxe, meaning it benefits from the engineering changes made to the original S7 without losing the S7’s unique appearance. The two original colors for the S7 and the S7 Deluxe were either Black or Mist Green, probably as these two paint colors were available in large volumes for not a lot of money after WWII.
The styling of the Sunbeam S7 and the S7 Deluxe has long been popular, thanks in no small part to the sweeping lines and fenders that were also popular on the American motorcycles of the era.
This bike was originally sold new via Godfrey’s Ltd of West Croydon to a local man, Donald Alan Lock, who later sold it to Gary Clarke of nearby Thornton Heath who kept it into the mid-1960s. It was one of the lucky few Sunbeams to end up in enthusiast ownership, as a result it had an engine rebuild in the early 1980s.
Approximately 20 years later in 2004 the bike was given an extensive restoration and it’s believed that it hasn’t been used on the road since. It was bought by a collector in 2019, and it’s now being sold with the current V5 and the original buff logbook, a collection of invoices dating back to 1979, various technical diagrams, some photographs of the restoration and a couple of 1980s motorcycling magazines.
During the restoration the bike received all new paint in the correct original shade of Mist Green, it also go new badges throughout, a newly reupholstered saddle, and new rubber tank pads. The bike is now presented in excellent overall condition with only a little patina, due to the fact that the bike has seen so little recent use.
If you’d like to read more about this Sunbeam S7 Deluxe or register to bid you can visit the listing here on Car & Classic. It’s being sold out of Hertfordshire in England.
Images courtesy of Car & Classic
Articles that Ben has written have been covered on CNN, Popular Mechanics, Smithsonian Magazine, Road & Track Magazine, the official Pinterest blog, the official eBay Motors blog, BuzzFeed, Autoweek Magazine, Wired Magazine, Autoblog, Gear Patrol, Jalopnik, The Verge, and many more.
Silodrome was founded by Ben back in 2010, in the years since the site has grown to become a world leader in the alternative and vintage motoring sector, with well over a million monthly readers from around the world and many hundreds of thousands of followers on social media.
