Reference: Vincent Comet/LE sidecar

Vincent Comet and LE sidecar

Every Vincent Comet/Meteor owner will be fed up with the old chestnut ‘It’s only half a twin.’ Reintroduced for the 1948 season, the stock 499cc Comet pushed out a healthy 28bhp/5800rpm measured at the crankshaft, which compares favourably with 23bhp delivered by the AJS Model 18/Matchless G80, 24.6bhp from an Ariel Red Hunter and 21bhp from the Norton ES2/Model 18. Suddenly, instead of being half a twin, the Comet becomes a gutsy big single in its own right. Which is exactly how it should be judged, your honour…

While we may need to accept the Vincent Comet as a gutsy big single, owners of post WWII Vincents – both single cylinder and V-twin models – have always accepted their marque as unconventional; after all, they have no frame as such. In this case unconventional isn’t bad, just different. And for the re-builder this difference can work to their advantage, as rather than undertake hernia inducing manoeuvres to remove the engine from a cradle motorcycle frame, place a workbench under the Vincent’s engine with both wheels clear of the ground, unbolt front and rear ends and wheel away in their entirety, and you are left with… the engine on the workbench. Certainly this description simplifies the job but it isn’t a difficult task.

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Vincent Comet and LE sidecarVincent-HRD Co Ltd, Stevenage, Herts liked both light alloy and intricate castings, including the cylinder head/s of both post-WWII single cylinder and V-twin models. The neat one piece casting includes integral rocker housings while the light alloy barrel houses a shrunk-in cast iron liner. Crankcase castings, covers and many detail parts are also cast in light alloy while the mudguards for all post-WWII machines except the touring models are in polished aluminium supported on tubular steel stays.

Since the Vincent family (Phillip Vincent backed by his father) took over the HRD brand and the first Models (A-E) plus Special Racing Model rolled off the factory workbenches, albeit it in tiny numbers, every HRD/Vincent had full rear suspension employing Phillip Vincent’s sprung triangulated rear subframe. History tells us Vincent initially built his own concept of the ideal frame, which was triangulated, but due to his observations of customer resistance to too much change in one hit, he reverted to the traditional diamond design for most models from 1931 onwards. In truth, the triangulated design applied to precious few models, as production levels at this stage were miniscule.

Despite giving way on main frame design, Phillip Vincent’s rear suspension system was to remain for the duration. None doubt Vincent’s mind was active with plans of future chassis designs but the practicalities of employing proprietary engines, with which for the most part he was unhappy, occupied even more of his thinking time. In interviews he stated only the Rudge Python engine came up to his desired standards, but for commercial reasons its long term use wasn’t viable for Vincent and despite trying many other units including Blackburne, Villiers, MAG and even one Cross rotary valve engine he predominantly installed JAP units.

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Vincent Comer and LE sidecarAfter a disappointing 1934 IoM TT, when specially assembled JAP engines failed, Phillip Vincent and Australian Phil Irving set to designing Vincent’s first ‘in house engine’. While often disagreeing, the duo made a fair team, Phillip Vincent full of ideas, the more extreme of which Phil Irving kept in check. Developing 25bhp at 5300rpm, the new unit appeared first in the 1934 season Meteor, which like the majority of models since 1931 employed a traditional style main frame diamond.

Further design resources were spent developing the 500cc engine’s performance to give the 28bhp Comet Special and 34bhp TT Model. Then in 1936 came the first 1000cc twin, the Series A Rapide. One wonders if Phillip Vincent hadn’t spent so much time developing and putting into production engines, would his radical post WWII rolling chassis employing the engine as the main stress member have appeared much earlier? Or would he have still been concerned about public opinion?

Through much of the war, while working on marine engine designs for the Air Ministry, Vincent and Irving could do little more than dream of the machines they would build when the hostilities were over. Like the pre-WWII Series A singles and twins, the new motorcycles had to be quiet, flexible, relaxed high speed touring motorcycles which with tuning could be made even faster. Although the Series A was the starting point, when the first post-WWII Series B Rapide was launched it was clear little remained of the original pre war models except the bore and stroke, duo brakes and rear suspension.

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Vincent Comet and LE sidecarQuite apart from its striking visual appearance enhanced with lots of polished aluminium one question was on everyone’s lips. Where’s the frame? Of course, the designers hadn’t forgotten it, simply they’d omitted it, instead relying on the massive V-twin engine as the main chassis stress member. In doing away with the traditional frame diamond, the pair had made their life easier as the large engine didn’t need to be shoe horned into a traditional frame with downtubes and the like in the way. As a result they were able to develop a 50 degree V-twin for a motorcycle with 2½ inches shorter wheelbase at 56 inches rather than the lengthy 58½ inches of the Series A twin. Instantly, handling was improved with no loss of straight-line stability.

Soon, some Vincent owners were tuning their Rapides, then the Stevenage maker took the next logical step by supplying the more powerful 1000cc Black Shadow. However, it’s not the 1000s but the 500s which interest us here. Vincent could have built an upright engined single with conventional main frame diamond to which Vincent's rear suspension system was fitted – after all, the concept proved successful before WWII. But they didn’t.

With its cylinder barrel tilted forward at a rakish 25 degrees, the new for the 1948 season Comet looked a fast single, even while displayed in the dealer’s showroom. As detailed earlier, engine apart the Comet’s rolling chassis shared much with its bigger sibling. Combining two-up comfort, better road holding than many rigid or plunger suspension rivals, the Comet was praised by many of the period testers, exampled by the standfirst of Motor Cycling’s scribe on 26 January 1950. “An 88mph high camshaft single of unorthodox design which justifies its place in a famous range of sporting motorcycles.”

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Vincent Comet and LE SidecarBought by Hertfordshire enthusiast Maurice Hallett as a solo from one of Eric Patterson's Kempton Park Autojumbles, this Series C Comet had been asleep in the previous owner’s lounge since 1991, only awoken each year for its annual MoT test and returned to its spot in the house soon after.

As would be expected with such a cared for motorcycle, it needed little preparation in Maurice’s home workshop before it was returned to the road as a high speed machine from the early 1950s. Fittingly, Tony Brown rode it in 2008 for the annual Stevenage and District MCC George Brown memorial run, held during July each year in memory of the legendary sprinter who was also a club member.

The ultra light LE sidecar, manufactured by the Lawson Engineering Co of Bishops Stortford, pitched up in Maurice’s workshop along with a Silk he’d bought. Originally, the LE was mated to the two-stroke twin by Silk, but Mr Hallett didn’t like the pairing and soon separated the motorcycle and sidecar. However, positioned alongside the Vincent Comet, he felt the two were made for each other, despite being manufactured 30 years apart.

Comprising a light glass fibre single seat body mounted on a tubular steel chassis with 5.20x10in BMC Mini wheel, the LE was in basically sound condition, needing little more than tidying and a repaint. An Irish friend machined mounting plates, into which Maurice’s brother Gordon machined lightening holes. Maurice helped and, advised by Phil Primmer, fitted and lined up the sidecar on the Vincent and the plot was ready for the road.

Vincent Comet and LE sidecarA year later, Tony Brown had three wheels on his wagon for the Stevenage Club’s annual run in memory of his father and gave the outfit an enthusiastic thumbs up. Months later, at Maurice’s invitation, it was my turn.

Having spent much of my teenage years in Hertfordshire, I’m reasonably familiar with the chosen test roads on the Walkern side of Stevenage and, having recently ridden another friend’s Comet, albeit a solo, it was simply a case of hopping on and opening the taps. Instantly, the superb set-up job of Maurice and Phil was apparent. In a straight line, powering the Comet around the chair or rear wheel braking to bring the sidecar around the Vincent it was spot on, and among the best set-up outfits I’ve ever ridden. In fact, the LE’s presence was dangerously easy to forget, but best remembered when passing parked cars and vans!

At The Classic MotorCycle we never put older machines through exhaustive, tyre shredding tests to squeeze the last few mph out of them. Instead, it’s more a matter of appraisal and comparison. And with regard to comparison, the Comet with LE sidecar was only marginally slower off the mark than the earlier ridden solo example. No top speed test was tried, but the job purred along at 60mph with seemingly plenty of power to spare. One imagines 70-75mph for the outfit a reality rather than a dream.

At the opposite end of the performance scale, the Vincent LE combination burbled along at a steady 25mph in top, though ‘gently does it’ was the order of the day if one didn’t change down before increasing speed. But knock the box down a couple of gears and the tap could be opened with enthusiasm. While our period Motor Cycling tester snicked up the gears at 25, 50 and 70mph, yours truly found the machine comfortable with upward changes at 15, 35, 45 and low 50s mph. Despite this modest use of the engine’s performance, acceleration was more than adequate for everyday town traffic and a self imposed 60mph top speed is the UK legal maximum on all unrestricted roads except motorways and many out of town dual carriageways.

Vincent Comet and LE sidecarWhile engine performance was as expected, the gearbox surprised. Vintage hand change and 1930s Burman gearbox are the business for yours truly, but by the time they reached the 1950s many rival products have the edge with regard to their speed of ‘crunch free’ changes. But on this occasion, clonk free changes were guaranteed, no matter how quick and nimble your feet are, in either direction. Certainly one has experienced far worse post WWII Burman boxes but none in over 40 years' experience have been better – a tribute the machine’s past mechanics and the current custodian.

Handling and steering with an outfit is a far more subjective topic than with solo machines. Drivers often want and are looking for different characteristics and the requirements of each rider can often be catered for by differing set-up and even sidecar choice. Many words have been written on the subject of sidecar wheel lead, toe in, body lean, tyre pressures and other variables, both real and at times imaginary!

Although never wishing a motorcycle combination for my modest collection, I do enjoy driving them and over the years have, I thought, developed many opinions on the ideal set-up. Then a few years ago I borrowed a friend’s outfit, comprising a single seat sidecar hitched to a powerful machine. Imagine the surprise on noticing the sidecar wheel axle had only about two inches lead on the motorcycle’s rear wheel axle. For a plot expected to cruise at 70mph, this surely was a hopeless set-up. Asking the question why, I received the answer a ‘smarty pants’ like me deserved. “It had to be that far back so the handlebars missed the windscreen on full lock.” Defeated, yours truly could only weakly utter ‘OK’. Proof of the pudding was this high speed outfit was stable in a straight line at all speeds, cornered well – even at speed and didn’t tug wildly on the rider’s arms. With this ‘learning curve’ in mind one can only reiterate the comments penned earlier; the lads did well when they mated this pair.

Vincent Comet and LE sidecarRegardless of whether you love, hate or are indifferent to Vincents, there is no denying they have among the best brakes of machines from their period. On a tarred granite road surface the 1950 Motor Cycling road tester managed to squeal his solo Comet to a halt from 30mph using both brakes in just 21ft, front brake alone 29ft and rear bake only 52ft. Truly impressive figures for 60 years ago, and even today not bad at all. Certainly, the weight of the LE sidecar took a little off the edge of the braking but a couple of practice emergency stops, out of sight of Maurice, proved the outfit more than able on the braking front. And while the front alone was sufficient and highly controllable when slowing for roundabouts and the like, dabbing the rear brake made light work of fast, sharp right-handers.

Comfort wise, the Vincent is as good as its maker intended and one imagines a few hundred miles per day when on the grand tour wouldn’t be tiring. While one (me, that is!) accepts the Vincent suspension works well and the machines handle well for the period one (me) doesn’t like watching them in action as the wheelbase seems to lengthen and shorten dramatically as the machine seems to hinge in the middle. This of course may all be illusionary, but the best thing to do when the machine's shadow is cast on the road beside you as you bowl along, is not to look.

The Vincent Comet of Maurice Hallett proved once again the 500cc single may be half the size of the 1000 but viewed as a lusty, gutsy single it’s an equally good choice and another one for the imaginary collection when the lottery ticket secures a fortune. Now if only I supported the lottery… bike

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