Saturday, September 6, 2014


I really enjoy motorcycle engineering. Mechanical engineering is always an interesting subject as the nebulous topics of physics and chemistry and metallurgy take real, solid form. Besides that, I like to hear a nice set of motorcycle pipes.

Motorcycle engineering is much more pure than automotive because of the smaller size and weight and the fact that everything: gas, electrics, engine, brakes, suspension, are all right there for your inspection. Issues that are minor in an automotive engine such as wet sump vs. dry sump oil system or the configuration of the cylinders becomes essential design choices on a bike. Engine width and height and cooling and carburetion are all much more important on the slim body of a motorcycle. The old adage of “KISS,” Keep It Simple … is so important, especially in the early days when engineering and technology were less sophisticated and much less reliable.

Even the multiple-cylinder configuration and angle between the cylinders is key to performance because you have to be able to straddle the engine. Small displacement bikes are often single cylinder or small twins, but, as the engine displacement increases, just what way you put these large cylinders matters. Of course, as you increase engine size, you can just add more cylinders. Cars followed that route going from twins to four-, six-, and eight-cylinders — including more crazy counts such as 12 and even 16 pistons. Bikes went that route too, although not often past 6 or 8. But finding room for all that iron between the rider’s legs was always an issue and a design choice.

For a small motorcycle engine, one or two cylinders worked best and there were many different ways to arrange the engine. But, as displacement grew toward 100 cubic inches, pistons got bigger and bigger and configuration becomes very important. Keeping it simple with only two cylinders led to V-twin designs. That keeps the overall height of the engine down from a vertical design and, by installing the V in line with the tires, gives a narrow engine.

Harley Davidson took this to the extreme by placing the cylinders directly in-line. They connect the pistons to a single crank pin on the crankshaft/flywheel using “fork and knife” piston rods. While this produced a very narrow engine, it had the adverse effect of hiding the second cylinder behind the first, a problem in an air cooled engine as the second cylinder didn’t get as much of a breeze while rolling down the highway and ran hotter. Harley further complicated things by using a single carburetor located between the cylinders and other simplifications that treated both cylinders the same regardless of the significant difference in running temperature.

Over the years Harley improved their engine designs significantly, but remain with this fundamental issue (although the Revolution engine from Harley addresses this to some extent by adding some water cooling).

But, as Marc Anthony said in paraphrase, "I came to praise Harley not bury him.” And I will be writing about the venerable American motorcycle and its engine evolution (get it, EVO). But that’s a story for another time.

Now days to tell the story of motorcycles, you have to discuss the Japanese invasion of bikes that began in the 60s. They changed everything by building bikes as complicated as a swiss watch, yet still reliable as a rock. But, again, that’s a tale for another time and was not a factor in the '50s.

What I want to talk about in this article is a large British V-twin that I always thought was a superior design to the Harley’s basic V-twin. By the simple step of offsetting the rear cylinder, Vincent was able to balance the two parts of the engine thermally and they added dual carburetors and matched exhaust to produce what was the fastest production motorcycle in the early fifties.

This article is about that British V-twin. Even with superior engineering and plenty of speed records, the company went broke. However, the Vincent is not quite extinct. Besides the few surviving models sold at extravagant prices in the world's classic cycle auctions, there are several modern re-creations of the famous brand and design, although most copy cats have lived and died in a shorter lifetime than the original they attempt to emulate.

Vincent Motorcycles was a British manufacturer of motorcycles from 1928 to 1955. Their 1948 Black Shadow was, at the time, the world's fastest production motorcycle. In 1955 the company discontinued motorcycle production after experiencing heavy financial losses. But, in the 1940s and the early ‘50s, the Vincent was a phenomenal bike, known for its speed and durability. It was the most popular bike of its time, and today it's a highly sought after collector's bike.

HRD was founded by the British Royal Flying Corps (RFC) pilot, Howard Raymond Davies, who was shot down and captured by the Germans in 1917. Legend has it that it was while a prisoner of war that he conceived the idea of building his own motorcycle, and contemplated how he might achieve that. It was not until 1924 that Davies entered into partnership with E J Massey, trading as HRD Motors. Various models were produced, generally powered by J.A.P. engines.

Unfortunately, although HRD motorcycles won races, the company ran at a loss. In January 1928 it went into voluntary liquidation. The company was initially bought by Ernest Humphries of OK-Supreme Motors for the factory space, and the HRD name, jigs, tools, patterns, and remaining components were subsequently offered for sale again.

Philip Vincent began building motorcycles in 1927. In 1928 he registered a patent for a cantilever rear suspension of his own design. With the backing of his family wealth from cattle ranching in Argentina, Vincent acquired the trademark, goodwill, and remaining components of HRD from Humphries for £450 in May of 1928 and the Vincent brand was born.

The company was renamed as Vincent HRD Co., Ltd and production moved to Stevenage, England. The new trademark had The Vincent in very small letters above the large "HRD." After World War II Britain had an export drive to repay its war debts, and the USA was the largest market for motorcycles. In 1950 the "HRD" was dropped from the name to avoid any confusion with the "HD" of Harley Davidson, and the motorcycle became “The Vincent.”

Vincent produced the Meteor and the Comet, and, by 1936, the Rapide. Eventually the factory began to produce the Vincent "Black Shadow," a hand-built motorcycle produced by Vincent HRD from 1948. The series “C,” which was introduced in 1949, had a 998 cc (60.9 cu in) 50 degree OHV V-twin engine running a 7.3:1 compression ratio.

The reason for its name "Black" Shadow was that the entire bike (including the engine) was colored black including baked enamel on crank-case and covers. The reason for the black on the crankcases is still disputed to this day. Some claim that the black color was for looks, others claim that it had something to do with heat transfer and dissipation. Whatever the original reason behind the painting of the engine, it was very different from anything else at a time when everything was polished and chromed. There were a small number (about 16) of White Shadows, machines made to Shadow specification but with the plain aluminum finish of the Rapide. Fewer than 1,700 Vincent Black Shadows were made, all hand-assembled.

Journalist Hunter S. Thompson wrote that, "If you rode the Black Shadow at top speed for any length of time, you would almost certainly die." and praised the model in his 1971 novel, Fear and Loathing in Las Vegas. I assume that the gonzo journalist meant die of exuberance … definitely with a smile upon your face.

The "Black Lightning" was a Vincent motorcycle designed and built in September 1948 at the Vincent works in Great North Road,Stevenage, Hertfordshire, UK, and produced from 1948 to 1952. At the time the Black Lightning was the fastest production motorcycle in the world.

Available to order, a standard Black Lightning was supplied in racing trim with magnesium alloy components, special racing tires on alloy rims, rear-set foot controls, a solo seat and aluminum fenders. This reduced the Lightning's weight to 380 lb. The 998 cc (60.9 cu in) air-cooled OHV pushrod V-twin specifications were always based on standard parts but upgraded with higher performance racing equipment. The Black Lightning had higher strength connecting rods, larger inlet ports, polished rocker gear, steel idler gears, racing carburetors, a manual-advance magneto, and it was available with compression ratios between 6.8:1 and 12.5:1. This resulted in 70 bhp and a top speed of 150 mph.

(For comparison, The Shadow had roughly the same bhp as the Kawasaki 750cc Triple introduced in 1969 and possibly the first crotch rocket!) Only 31 Black Lightnings were ever built before production ended in 1952 because of Vincent's financial problems. Check those numbers. Around 1700 hand built Black Shadows and only 31 Black Lightnings, the "production" bike. For that reason, there are often debates if a given classic Vincent is a "Shadow" or a "Lightning." Especially if they've been modified after leaving the factory.

On the morning of September 13, 1948, Rollie Free raised the American motorcycle speed record by riding the very first Vincent HRD (it is debated as to whether it was a Black Lightning or Black Shadow), owned by the California sportsman John Edgar and sponsored by Mobil Oil, to a speed of 150.313 mph. However, in Europe and elsewhere, it was the officially sanctioned Fédération Internationale de Motocyclisme (FIM) record that mattered.

In 1949 The Motor Cycle magazine offered a trophy and £500 prize (£20,000 in today's money) for the first successful all-British attempt on the World Speed Record, held since 1937 by BMW at 173.54 mph. Reg Dearden, a motorcycle dealer at Chorlton-cum-Hardy in Manchester fitted a supercharger to a brand new Black Lightning and made extensive modifications including strengthening and lengthening the frame by about 6 inches. Phil Vincent personally supervised the work, which took months to complete.

The supercharged Vincent changed hands several times but never made a record attempt. In 1999 journalist Mick Duckworth had a test ride and wrote a feature article for Classic Bike magazine. In October 2008, the supercharged Vincent Black Lightning was sold for £221,500 at the Stafford Motorcycle Show, setting a record as the most expensive motorcycle ever sold at auction in the UK. So Vincent ended up with a record after all, but it, like all the other records, may be beat in the future.

After the Second World War, the German NSU factory (originally named Neckarsulm Strickmaschinen Union in its knitting machine days and later a bicycle manufacturer) battled English machines (Vincent and Triumph) for top speed honors through the 1960s. NSU increased the World Record to 180.29 mph in 1951, and in 1953 the 500 cc World Champion Les Graham was to make an attempt for the UK but was killed in a crash in the 1953 Senior Isle of Man TT.

The 1951 NSU, FIM record of 180 mph was finally bested by Vincent in 1955 (184 mph) by rider Russell Wright in New Zealand. That was beat by Triumph in '56 establishing the Bonneville Salt Flats in Utah as the place to race. In 1956, NSU recovered the title followed by three advances by Triumph brand to 245 mph ten years later before Yamaha took over in 1970 at 271 and change.

(Think for a moment on the irony that a German company, later bought by Volkswagen, and named for Knitting Machines was in the running for the fastest bike in the world. There's a strange connection for you James Burke — look him up if you don't get the reference.)

Yamaha finally broke the 300 mph barrier in 1975. After 1970 the Bonneville Salt Flats and speed records were dominated by various Japanese brands and Harley. The current record of 376 mph was established on a custom bike with twin Suzuki motors in 2010. This year, sadly, the Salt Flats were too wet and the usual activities had to be canceled.

Vincent motorcycle land speed record holder Rollie Free featured in one of the most iconic photographs in motorcycling history wearing a bathing suite at the Bonneville Salt Flats.
At a Vincent Owners' Club dinner in the summer of 1955, Phil Vincent announced that the company could no longer continue in the face of heavy losses and that production of motorcycles would cease almost immediately.In 1955, one week before Christmas, the last Vincent came off the production line and was promptly labeled "The Last”.

Fritz Egli, a specialist frame manufacturer based in Switzerland, produced an Egli-Vincent, and around 100 were produced between 1967 and 1972. Egli-Vincents were subsequently built under license in France by Patrick Godet. JMC Classics also produce new Egli framed Vincents in the UK.

John Mossey, one of the key engineers and designers at JMC Classics, has built up an unparalleled reputation over the last 20 years for his expertise in the restoration of classic motorcycles and development of the new build JMC Egli-Vincents and JMC Norvins.

(JMC Classics was formed in October 2008. Its business goals are “to provide an unparalleled service for the restoration of classic motorcycles and specialist new build projects of the JMC Egli-Vincent and JMC Norvin.” The Norvin looks to me like a Norton Manx with a Vincent engine, but this becomes a bit of a rabbit trail in an article about the '40s and '50s.)

In 1996, a new motorcycle company was formed by three individuals, Rodney Brown (a metallurgical engineer), Terry Prince (a Vincent enthusiast and specialist), and Ron Slender. Brown provided the financial start and along with Prince were the founding directors, with Slender specializing with business development post-production. The company was named after the three, RTV Motorcycles. Its ambition was to produce a modern day classic Vincent motorcycle that could be marketed, in reasonable volumes, worldwide. RTV used a redesigned and modernized version of the Vincent engine, engineered by Prince, with an increased capacity and in an Egli-style frame. The motorcycles were to be built individually by hand. The first factory prototype RTV was built in 1998, other RTV prototypes were in various stages before the company went into voluntary liquidation towards the end of that year.

Vincent Motors USA founder and president, Bernard Li, acquired the Vincent trademark in 1994 and formally launched Vincent Motors USA in 1998, spending about $2 million building prototypes that resemble the original Vincent but utilized modern components like the Honda RC51 V-twin engine. Vincent Motors was based in San Diego. A resurrection of the Vincent name by this organization is now unlikely as the RC51 engine is out of production, and Li was killed in a motorcycle accident in Arizona in 2008.

There’s also a motorcycle produced in Australia bearing the Vincent name. However, the multiple attempts at restoration of the Vincent name have not enjoyed the success of the resuscitated Indian brand, but only time will tell the final chapter.

Until the name is restored, you can always enjoy Richard Thompson, OBE (Order of the British Empire), British songwriter and guitarist's "1952 Vincent Black Lightning” on his 1991 album Rumor and Sigh. Thompson later said, "When I was a kid, that was always the exotic bike, … the one that you went 'ooh, wow.'”

Wow indeed!

1 comment:

  1. For those interested in more technical details on the Vincent big twin, I suggest this article from 1945 happily available on the 21st Century Internet: