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Classic Bike Newsletter

Girder forks

By Richard Rosenthal, pics Terry Joslin > Originally published March 2006
1929 side sprung Druids from a Norton 16H

1929 side sprung Druids from a Norton 16H

Feared by some, girder front forks were a light, reasonably strong early solution to steering and front suspension. Today, most are at least 50 years old, so need regular checks and maintenance to make sure they remain safe to use

During the early days of motorcycling, a number of front fork designs were tried. Among them were rigid cycle forks with or without bracing, sprung girder, leading link, trailing link and telescopic. Additionally, adventurous makers patented designs such as hub-centre steering –  supported on one or both sides – and Duplex steering, as pioneered by OEC, which had a telescopic element too.

Many early pioneer motorcycles relied on bicycle-type rigid forks with no suspension, which were prone to breakages due to the extra weight and higher-than-cycle speeds, plus the poor road surfaces. Engineers sought various solutions to remedy the situation, including the enlightened Rex Motor Manufacturing Company of Coventry, a company, which was among the pioneers of telescopic fork design in the mid-Edwardian period. But the idea favoured by many was the sprung girder fork. Among the leading designers were pioneers Druid, who favoured a side sprung principle, Triumph with a rocking action, Brampton with their Biflex, offering both rocking and up and down movement, leaf-spring control from makers like Indian and Sunbeam and the famous Webb, with centre-spring control.

Girder motorcycle forks overhaulMany other variations on the theme were produced – some useless – while many others simply didn’t catch the trade buyers, eye or were developed by makers who lacked the cash to see the project through, and were replaced by something better, more conventional, or commercially available from proprietary makers such as Webb, Druid or Brampton. Many of the leading makers built their own forks, while others bought proprietary items in; here, we look at one leading example, the Druid side-sprung fork with steering damper from a 1929Norton 16H.

The spindles, spring/s and fork/yokes spindle holes will all wear with use, no matter how thorough the motorcycle’s maintenance. The fork spindles slide though their holes easily, but with no side-to-side or up and down play. Often, most wear is found in the bottom yoke holes and on their mating spindle, as the forks seem to pivot with more force about this point.

Replacement fork spindles should be made from a high tensile steel, such as EN16T, which is a shock resistant tough (55 tons tensile) manganese-molydbenum steel. EN16T fine turns well or can be ground to size. Ideally, to produce true threads, either screw-cut or use a die holder in the lathe with a high speed steel (HSS) die. Some, skilled with hand die holders, can cut true threads but mine would be wobbly, leading to poor fastening of spindle nuts. Never become tempted to use other materials like silver steel (too brittle), bright mild steel (not tough enough) or many of the range of stainless steel alloys (while some may be suitable you may not know the composition of the stainless steel alloy or its qualities) as they are all totally unsuitable, dangerous and, besides, EN16T is available from many specialists stockists at autojumbles, by mail order or directly.

To aid lubrication
Some original spindles had either a groove or flats machined into them to aid lubrication. This needs replicating, and handbooks or parts diagrams may illustrate the positioning of the spindle with groove/flat if appropriate. Although I’m sure I’m teaching granny to suck eggs, remember not to create a sharp angle where the spindle is machined to a smaller diameter for threading or to fit through the link. Instead, machine a slight radius to lessen the risk of shearing at this point.

Girder motorcycle forks overhaulMany more recent forks have bushed spindle holes, in which case the old bush is pressed out and replaced by new. Some one make clubs and occasional specialists stock appropriate bushes. Old bushes can be either pressed or, if difficult, machined out – another job for the competent only. Usually, they are thin-wall phosphor bronze structure, with often a 0.001 to 0.0015in interference fit into the hole. Always press them into place – never strike them with a hammer, as they easily bruise. Once fitted, the bushes need minor reaming to restore to spindle size as they will have closed marginally on pressing into the hole. Ideally use a reamer with pilot (guide) spigot to ensure work is true.

Enough ‘meat’
Many veteran and vintage girder forks were un-bushed. If there is enough ‘meat’ it’s possible to either ream spindle holes along their entire length, or machine the ends of fork cross tubes to accept thin-wall bushes. The latter is by far the best option, as when they’re worn again, the bushes can be pressed out and renewed. Both procedures require a high degree of accuracy. Phosphor bronze is an ideal material for these bushes. In extreme cases skilled restorers have fabricated new cross tubes with lugs/spigots, dismantled the fork blade structure, fitted and then brazed or silver soldered them  together – work way beyond my ability!

Extreme rust, age and wear softens and weakens springs. Some sources stock common spring sizes, or replicas can be made to a pattern or accurate drawing by specialist spring makers. In some cases, stronger-rated springs are needed for heavy duty use, eg hefty machines or for sidecar work.

While it’s possible to chrome or nickel plate new, un-rusted springs to good effect, once even surface rust has appeared, the job is near impossible for a sound long-term finish as it’s impossible for the metal polisher to polish the inside of spring coils. Some use chemical cleaners, but I’ve yet to see one that works perfectly. However, for many machines the girder fork springs were painted so if they’re second-hand but in good order, they can easily be blasted clean to accept any of the finishes we may consider.

Girder motorcycle fork maintenanceDue to poor assembly, the spindle holes may have elongated, internal threads – if present – may have been damaged, rust could have caused wasting and in, extreme cases, fatigue cracks may be evident. Many links were malleable iron castings which – unless you’re considering making a large number – are not viable for a business to reproduce. An alternative used by many is to machine them from a suitable mild steel. Again, seek help if unsure.

Many later girder forks are simply greased through conventional grease nipples, with makers recommending intervals of 250 to 1000 miles. I favour lubricating every 250 miles, working on the principle that if the job is overdone, no harm will occur, while under-lubrication will hasten wear.

Some veteran and many vintage models were fitted with oilers. Most vintage models had decent sized holes enabling the use of a thicker oil – such as SAE50 – which lubricates for longer than thinner oils, as it escapes at a slower rate. Veteran and earlier vintage machines often have smaller holes in oilers, making a thinner oil more desirable. Unfortunately, some veterans have no oilers, lubrication is undertaken by laying thin oil across link/friction washer joints in the hope it works in or loosening nuts and links to feed oil onto spindle.

Maker’s interval advice – if there is any – varies. Usually, lubrication in each pre-run check is sound practice. bike

Triton test

Tri-umph engine and Nor-ton frame equals Triton

Tri-umph engine and Nor-ton frame equals Triton, and this one’s immaculate

When standard just won’t do, in comes the special builder with the Triumph-engined, Norton-framed ‘Triton’. It’s not an easy route and it is quite possible to create a dog of a bike, but not in this case as Phil Mather finds out…

Everybody has a dream bike – the machine they’ve always wanted to own. Maybe it’s the bike they aspired to when they first got into motorcycling, the star of an Earl’s Court Show or a high street dealer’s window display, theirs for a price they could never afford.  Maybe it’s the bike their mates were always talking about, the fastest production motorcycle ever, the one you could ride to a race circuit, take the lights off, race, and win. They were all going to get one next year, or the year after, you included – dreams and schemes fuelled by frothy coffee or several pints of Best. Maybe it’s a special, a flash of chrome, a blast of sound and the whiff of Castrol R, gone before you could get a really good look and so fast you were never, ever, going to get a second chance.

Mike Cookson’s early motorcycling may have been done on a lowly Bantam, but the bike world was changing fast in the late 1960s – goodbye TriumphNorton,BSA, hello Honda – and the rest. Dreams, for the most part, were becoming attainable reality, and for a very long while he was the happiest of happy bunnies, owning a succession of oriental superbikes. All this was eventually to change, however. A regular diet of scurrilous rags like CBG nurtured a hankering for machines that clank and wheeze and bang, and in time he narrowed the field down to just two – a BSA Rocket Gold Star and a Triton.

Triton road testBut where would he find such exotica? Bikes that were advertised were either too expensive, a common phenomenon with dream bikes, or already sold – another common phenomenon. In a bid to turn up a hitherto undiscovered gem, he joined the local branch of the VMCC, only to find himself in the company of a dozen or more like-minded dream-seekers. He tried buying a box of bits – well, several boxes, actually – that purportedly amounted to a pre-unit BSA twin, with a view of building an RGS replica, but as is always the case the list of missing components soon equated to the size of a telephone directory. So in the end he employed the only practical tactic – patience.

News eventually filtered down the grapevine of a Triton for sale in Yetminster, North Dorset. It hadn’t run for about 10 years but it was complete; success at last, or so he thought! There followed a period of on-off decisions on the part of the vendor as to whether he would part with the bike or not, which was doubly frustrating for Mike as, having once seen the machine, he was already planning what he needed to do to it to turn it into his Triton. A deal was eventually struck, however, and Mike bought a new garden shed to celebrate – well, to house the new project, actually.

Tritons come in all shapes and sizes, that being the nature of the beast. The racing variety can be as minimalist as you like, providing there’s a Triumph engine in a Norton Featherbed frame with, I guess, a wheel at each end to keep things from dragging on the ground. Road-going versions, on the other hand, range from the purposefully pugnacious to the positively florid – just seek out a copy ofMotorcycle Mechanics with the photograph of its project bike ‘Coloured Sound’ on the front cover if you don’t believe me. Personally, I think a bike with sporting pretensions has to be well engineered and devoid of junk – oddly shaped bits of glass fibre hung on with Jubilee clips just don’t cut it. And I’ve never been able to get my head around the concept of a ‘racing’ dual seat, especially one with a large hump at the back, designed, no doubt, to accommodate a toolkit, thermos flask and moderately-sized kitchen sink. Neither has Mike, so with spanner in one hand and the Unity Equip catalogue in the other, he set about putting matters right.

Triton road testWith the glassware ditched he was left with a very practical combination of ’57 wideline frame housing T120 bottom end with T140 barrels and 10 stud head. The engine and standard Triumph pre-unit gearbox with four-spring clutch were held in place with alloy Converta engine plates. A very pretty, if slightly dinged, three gallon alloy petrol tank adorned the frame top rails and standard Norton hubs laced to 19in flanged Borrani alloy rims were fitted front and rear. Mike repaired the tank himself and had the wheels replaced with stainless spokes, then he added a rear frame loop, alloy mudguards and brackets and a Manx seat. The original long Roadholder forks were scrapped in favour of the short variety with external springs, mounted in new yokes with 7 3/8in centres – Mike chose the wider yokes to give himself the option of fitting a different front brake in the future, although he retained the John Tickle twin leading shoe backplate that had been installed by the previous owner.

The face-lift was completed with a new pair of Gold Star pattern silencers and clip-on handlebars from Unity, polished alloy Amal handlebar levers, and a chrome-plated headlamp shell from Bantam John’s stall at the Netley Marsh jumble. The speedo and rev counter were treated to new chromed bezels from Britbits and then mounted on an RGM alloy bracket. RGM also supplied the alloy rear brake backplate. The rearset footrest assemblies originally came from Rolston Precision Tooling in Oldham, and Mike subsequently modified them with rose joints from Barlycorn Engineering.

Triton road testThe Triton was beginning to come together the way Mike wanted, so, he figured, it was time to get it on the road and cover some miles. Unfortunately, the bike was reluctant to go along with this – it didn’t start well, it didn’t run well, and it vibrated a LOT. He broached the subject with the previous owner who insisted that it couldn’t vibrate anything like he claimed since, when he had rebuilt the motor, he had gone to great expense to have the crankshaft balanced. Still puzzled, but somewhat reassured, Mike resolved to work through a checklist of the more obvious problem areas.

To start with, he exchanged the Mk2 Concentric carburettors for a handed pair of 932 Mk1s, discarding the cable operated choke slides. Happy with a noticeable improvement in starting, he entered the ‘Spirit of the Sixties’ run in early 2002, only to drop out with ignition failure. Whether it was the ignominy of coming home on a trailer, or simply the result of thinning patience, he ripped-out the Lucas Rita system that had come with the original bike and installed a Boyer Bransden set-up with MF battery. If that sounds a little drastic, his experience on the BSA rebuild had taught him that it was better to fit parts he knew and trusted rather than try to eke extra miles out of components whose past history was unknown. The Boyer sender was housed in a Kirby Rowbottom case and the electrical boxes and ignition coils were mounted on a platform underneath the front of the petrol tank. At the same time he fitted an L P Williams high output 12-volt alternator kit.

Up and running again – and this time things really were better, although the vibration was still there and it seemed to be getting worse. At this point, if you’ve ever been there, you’ll know how unhelpful the ‘how much vibration is too much vibration’ debate can be. Supporters will admit immediately that all British vertical twins vibrate, but after all, wouldn’t you expect them to? Isn’t that part of the bike’s character? Of course, some bikes vibrate more than others, you’ve just got a bad one, but you’ll get used to it. Detractors, on the other hand, scoff harshly at a motor never designed to displace more than 500ccs; at compression ratios better suited to a Clubman’s Gold Star; at a ridiculous riding position for a road bike – and the soaring price of a loaf of bread. None of which is in any way productive, and does absolutely nothing to allay fears that sooner or later something, that timely intervention could have avoided, is going to go seriously wrong.

Triton road testWhile fitting the new alternator, Mike had noticed a tiny amount of what he describes as ‘backlash’ in the crankshaft. Bearing in mind his attention to detail in all other areas, and not forgetting the earlier assurances that the bottom end of the motor was in the finest of health, we’ll all have to forgive him for not wondering how this could be, although after the drastic turn of events that was about to unfold, he often now ponders the fine line that divides trusting to luck from leaving nothing to chance.

At a loss as to how to resolve the vibration problem, apart from securing his dentures with Blu-Tac that is, Mike entered the Triton on the local VelocetteOwners Club Bob Foster Run with the prospect of a gentle amble around Dorset, rounded off by nothing more stressful than the choice between cake or buttered scone to go with the end of event cuppa. But for him there was to be no happy ending – the gremlin that had dogged the Triton from day one was about to rear its head, big-time. The crankshaft snapped across a big end journal, bending the connecting rods and smashing a hole through the crankcases. It hardly seems possible that such a catastrophe can be described in so few words, but there it is – no high drama chain of events, no high speed duel leading to a missed gear change coming out of the final corner before the start/finish line, just a pobble down to the coast and a blown motor.

Inspection seemed to suggest that the crankshaft had been broken all along, but because the break hadn’t been clean and because the two halves of the crank were effectively held together on each side by the crankcases, the engine had continued to run. Whatever the truth of the matter, it was back to the garden shed for some serious spanner-work.

Triton roadtestMiraculously, Mike was able to weld the crankcases back together – pre-unit T120 cases have been out of production for more than 40 years, remember – and Peter Dear from Trumpits in Bournemouth supplied a replacement crank from a unit motor. A needle roller bearing was fitted in the drive side crankcase half and Mike pushed the boat out (or should that be the plastic!) and bought a pair of forged 7075-alloy rods from Allens Performance in Nottingham and a rotary oil pump from Morgo. The ‘racing’ camshafts that had come with the bike looked well past their sell-by date, so they went in the bin and new E3134 Bonneville cams and cam followers were installed. That just left the wording of a very polite note to Santa Claus and the Boxing Day treat of fitting a Unity rocker oil feed and cartridge oil filter conversion, braided stainless oil hoses and a T160 kickstart lever – this last item, so Mike advises me, is much coveted among Triton owners due to the extra leverage it provides for spinning-up the motor; T160 owners be warned!

Not one to be defeated, as you’ve obviously gathered, Mike was back on the Spirit of the Sixties in 2003 and this time the Triton went the distance and picked up the trophy for Best Special. The pot stands on his sideboard next to one from his local VMCC section – Crank of the Month, awarded, following the Bob Foster episode, for most miles travelled in the recovery van. Hmm, the ups and downs of owning a classic motorcycle… And so you might well think that was that, but hardly had the Solvol Autosol sheen time to dull when the inlet valve pushrods broke. Now that’s an easy one to fix, or so you’d think, but the replacement pushrods broke, too.

Once more delving into things mechanical, Mike concluded that the ‘extra strong’ valve springs that had come with the original motor were the culprits. They had caused the excessive wear on the cams and followers, and, when the new cams had been fitted and the lobes restored to their correct height, the springs had become coil bound on full lift, overloading the pushrods. A set of Terry springs put matters right.

Triton road testSo, is this where our story ends? Mike’s Triton was now up together and running just as well as it looked, his dream of owning and riding a legendary special fulfilled. Well I’m not sure you can actually own your dream bike because effectively the dream then becomes reality. In any case, Mike feels there is still some way to go before the bike is just how he wants it. Or is that the outlook of all special builders, seeking to improve?

He has already tried a belt primary drive but didn’t like the set-up in conjunction with the crankshaft-mounted alternator. Possibly a little overcautious, although you can understand why, he also felt things were getting too hot for comfort inside the primary case without the cooling effect of the oil – all in all he was happier running a chain. He still plans to fit a different front hub – a four-leading shoe Grimeca unit when he can catch the bank manager in a weak moment. That will be coupled with a Triumph conical rear hub, drilled and modified to look like a Manx hub, and both wheels will be fitted with 18in rims so that he can use modern, sticky compound tyres. And, of course, he’ll need an extra-wide Mick Hemmings swinging arm with taper-roller bearings. But will there be anybody out there prepared to race, we ask ourselves. I expect if he waits long enough, some mad fool on a Norvin will turn up and rise to the occasion; after all, Mike has the patience. All I need is a Featherbed frame and a Lightening motor and a garden shed to put it all together in – dream-on sunshine! bike

Triumph Bonneville

Triumph Bonneville

Triumph Bonneville

With the Triumph Bonneville celebrating its silver jubilee, the VMCC chose to offer up one such machine for their Christmas raffle prize. Always keen on a bargain, Jim Reynolds went to sample his quid’s worth…

Unless you’ve lived live in a cave somewhere for years, you’ll know that this is the 50th Anniversary Year of Triumph’s Bonneville. It’s arguably the world’s most iconic motorcycle, a machine that’s been feeding dreams of riders from the late 50s Rockers to today’s reborn types who remember the name from their youth.

If you want a measure of just how iconic, consider that when Triumph was reborn in 1990, there were only three of the old Meriden personnel employed at Hinckley. Tester Jock Copland was one, and the old hands didn’t talk to anyone about what was happening. One Meriden veteran I know was quite offended when he recognised Jock taking a mysterious machine into an anonymous building in Coventry, and though he had seen my friend, firmly closed the door and preserved the secret. ‘Talk and you walk’ was the clear instruction at what some said was Triumph’s new research base. Nobody talked.

Triumph Bonneville road testThe only nod to heritage in the new range was the model names: Trophy, Daytona and later Trident. The putative Classic Bike Guide had a 1200cc Trophy for a few days and its performance reached a level few riders of older bikes could comprehend; the few seconds from a second gear roundabout exit to an indicated 100mph were in a different dimension. Triumph was a thoroughly modern motorcycle aimed at the future.

Study the catalogues the young company has produced each year and you’ll see a gradual acknowledgement of its history. Quite right too, because Triumph has a record of getting it right in hard times, when other makers are wringing their hands, wondering how to survive. What’s more, they were brave enough to introduce a parallel twin in recent years, so the Bonneville remains an attainable icon. Look at prices of the 1950s and early 60s models and you’ll see a steady rise that confirms the Meriden product is the one attracting clever money; I spoke to a man recently who’d just rebuilt a 1968 T120 and was taking it to the Gaydon Anniversary bash to offer it for sale. He’d been advised to ask £18,000. I don’t know if he sold it, but offer it up as evidence of the Bonnie’s standing.

However, here’s a chance to own a pretty smart specimen for a mere one pound Sterling. I don’t think they’ve ever been that cheap on the open market at the very worst of times. Don’t think that there’s any guarantee that you’ll get this bike if you do lay out a quid or few, but you will have a chance as it’s the star prize in this year’s VMCC raffle and the single quid is what a ticket costs.

Triumph Bonneville road testAs we were caught up in the Bonnie’s Birthday Bash, I asked if I could have a ride on this very smart example of the US spec 1968 T120R, with its high bars and teeny fuel tank. Don’t be misled by that R suffix, you non-Triumph buffs, it simply stands for Road – though clearly not the model to load up and undertake long hours at motorway speeds, it is, nevertheless great fun on the back roads.

James Hewing, VMCC CEO, explained that the bike was at Brian Slack’s place, the man they call on to give raffle bikes a look over, as headquarters was undergoing building work.

Brian was a structural engineer and his motorcycle engineering is a blend of self taught and acquired. His dad was into bikes and his wife Ann worked at Ingell’s of Derby, BSA main agents. He’s also worked as spanner man to the likes of Ron Haslam and Charlie Williams and pride of place in Chez Slack goes to a lovely colour drawing of Charlie Williams en route to TT victory on a Yamaha Brian built for him.

Triumph Bonneville road test“Try the clutch on my Beesa,” he suggested, pointing to his A10. I have arthritis developing in my fingers, but I could lift the clutch with one finger. Impressive. He does prototype work for some big names and is currently working on an update of the BSA clutch. Asked by a club member why his oil pumps always worked, he pointed to the rig he’s built to lap them in, using a  mix of diesel and T-Cut; that didn’t come out of a factory manual.

He apologised, as the Bonneville had only come in recently, giving him time to check the basics, but a bruised right foot, courtesy of a dropped engine, meant he couldn’t start it up and check it properly, but come time to start it, a quick tickle of both carbs and a swinging kick had it fire up straight away. Those silencers may look effective, but the bike certainly has an impressive exhaust note and errant Volvo drivers should be able to hear you coming 100 yards away.

The clutch didn’t feel right. Brian had warned of a mysterious knocking sound as it cleared, but had only had time to check and oil the cable. It went into gear with a lot more than the characteristic Triumph clonk, more of a kerrrrlonk as the dogs engaged. This was a bike that would clearly be better if a knowledgeable man like Brian had been able to ride it around the block and do some basic sorting out. It spluttered when the throttle was opened too, its twin carbs clearly out of synch. Oh dear, it was going to be one of those days when a pretty bike got temperamental and played up, rather like the runner-up in a Miss World competition on the way to a press conference.

However, by then Brian was in snapper Wilko’s car and en route to some photogenic setting, so off the Bonneville went in pursuit, needing a fair old fistful of throttle to get away cleanly. I caught up in traffic, but unless I had the bike in second gear approaching a stop and could just nudge it into neutral while still on the move, the clutch wouldn’t clear enough to allow selection of neutral at a standstill, and when I was caught out at traffic lights and had to pull the lever in and keep the bike in first gear, the clutch began to drag.

Triumph Bonneville road testPlease don’t read too much into what is an honest account of the bike. It wasn’t a dog tarted up to impress, but it did need the careful little touches that can transform a traditional British motorcycle from a right pain into a real pleasure. It’s only slight adjustments that are needed, but you need a man with mechanical knowledge to do those tweaks.

This Bonneville needed to get to about 3000rpm to operate smoothly, and once out in winding country roads it delivered:crisp acceleration, slick gearchanges and sure footed handling through unknown bends. The front brake is the BSA-Triumph Group’s eight-inch tls unit that was the standard to which others aspired in the late 60s; please don’t write in and ask about the disc brakes available around the time of this bike’s birth; few more effective cures for constipation than early motorcycle discs have been found.

This not quite bonny Bonnie loves open roads where its medium speed cruising ability shines through. It’s geared to give about 17ish mph for every 1000rpm in top, so 4000 will give a speed nudging 70mph. At that engine speed it’s smooth and relaxed, however I wouldn’t want to push it much higher with those high, wide handlebars – the windblast would be considerable, but down a country lane those big bars combine with the slim fuel tank to make this a supremely flickable bike; Remember Kawasaki’s adverts that told the world that their whatever model was more flickable than a bogey. Whoever heard of anyone this side of Samson trying to flick, or even lift a set of wheels from one of Sir Nigel Gresley’s Pacifics or some lesser locomotive?

Most famous Triumph Bonneville of allIt’s a very handsome machine, this Bonnie, a reminder of Triumph Meriden’s good eye for colours in its combination of silver and a metallic red. It was a first-kick starter from initial acquaintance and when I got it out in the country I found I didn’t need the troubled clutch for upward changes.

I understood, from a good factory source, that the four-speed box with its many fine pitch engagement dogs could not be persuaded to change without using the clutch, but this one did it effortlessly.

Back at VMCC’s HQ, James Hewing assured me that the clutch centre was at fault and that a replacement was on order. Good; it certainly needs it and whoever wins this Bonnie, when Brian has sorted it, should have a jolly good motorcycle. bike

Vincent Black Prince

1955 Vincent Black Prince classic British motorcycle

1955 Vincent Black Prince

Vincent’s Black Prince rode at the vanguard of a brave campaign. It was a visionary product, offering rider protection and clean lines in 1954, but the motorcycle buying public, traditionally a reserved bunch, didn’t take to it. Mike Lewis tells the story…

Effective armour and high speed rarely combine in nature, save in those instances where man has defied evolution. Such combinations are usually memorable, as when Edward of Woodstock carried a weight of protection into battle on his powerful charger during the 14th century, or when British Railways standard class 9F locomotive 92203 hauled heavy freight at up to 80mph during the middle of the last century.

History bestowed the epithet of ‘The Black Prince’ in both of these cases and the title seems to suit the heavily shrouded flagship model of the fourth series of V-twin motorcycle from Vincent Engineers (Stevenage) Ltd, which made its public debut at the 1954 Earls Court Motorcycle Show.

Philip Vincent had begun experimenting with glass fibre applications after WWII, eventually designing a water-scooter called the Amanda that was a forerunner of today’s jet-skis. Consequently, the so-called Series D touring models (including a stillborn single-cylinder Victor prototype) marked a departure from the minimalist Vincent-HRD design philosophy (the famous initials were dropped from 1950).

Extensive glass fibre bodywork was the most distinctive feature of the new range, its execution reflecting typical Vincent go-it-alone innovation. The Black Prince benefited from engine components selected to Black Shadow specifications, along with tighter engineering tolerances than the Rapide-based Black Knight.

Vincent Black Prince classic British motorcycleWeather protection and streamlined design became new selling points as the small Hertfordshire-based firm felt sufficiently confident in the quality and appeal of its product to abandon its established image of a stripped-down high performer. Such a move speaks volumes about the venturesome nature of its proprietor, Philip Vincent. Engineering graduate Vincent had never been afraid to lead the market, though he must have been aware that full enclosure had simply not created a satisfying motorcycle since the quirky Ner-a-Car of 1921.

Retired BT engineer John Daniels, now 71, remembers this bold strategy well. A lifelong Vincent fan, his admiration for the new models in 1955 outstripped his funds, which nevertheless ran to the purchase of a year-old Comet for £120 from his local bike shop, Gray’s of Birmingham. “I never thought of it as ‘half a Vincent’, since it performed so well at everything,” he says. “I sold it for £100 when my first daughter arrived, but bought it back again when the new purchaser kept falling off it. I still have it, as a basket case, awaiting restoration in my workshop.”

However, the prospect of a full V-twin remained enticing and John was particularly delighted to get his hands on a Black Prince exactly 40 years later for a low five-figure sum. “It was the ultimate V-twin as far as I was concerned,” he recalls. “The last of the Vincent line, with all that accumulated status.”

The Black Prince had been standing idle since the 1970s and needed thorough cosmetic refurbishment. John, who is a former executive committee member of the Vincent Owners’ Club, kept to standard specification wherever practicable. He praises the VOC Spares Company (01925 753367), which is allied to the owners’ club although it operates independently, from premises in Cheshire. “I can get just about any part I want delivered to me the next day,” he enthuses.

Black Shadow A previous owner has substituted a five-inch diameter Smiths speedometer from a Black Shadow and John will eventually replace this with the standard three-inch item. His electrical engineering background dictated that a solid-state voltage regulator should replace the electro-mechanical original, located behind the engine, although he resisted the temptation to upgrade to 12v. NGK spark plugs and plug caps have long ago replaced the KLG originals.

After sending the glass fibre off for a professional respray, John applied new gold leaf pinstriping to the front mudguard, continuing the line below the fuel tank to the rear cowling and down beneath the numberplate. He tells me that the black Perspex windscreen could be specified as an option from the Stevenage works, its narrow curvature allegedly resulting from heating against an oil drum former.

Vincent Black Prince classic British motorcycleAt first glance, the Black Prince looks as fiddly to work on as any modern fully faired sports tourer, yet access is surprisingly simple. Loosen a nut on each end of the swinging arm spindle and the entire rear cowling pivots on a hinge behind the petrol tank, coming to rest almost vertically. Support in the upright position comes from a folding prop stand that engages with a lug in the swinging arm on the nearside, making rear wheel maintenance and removal straightforward.

The swinging arm supports a shaped metal splashguard, the rear cowling acting in place of a full mudguard. A single Armstrong damper unit bolts to the rear of a short tubular spine of 1 1/8in diameter, which bolts to the headstock. A second Armstrong unit forward of the headstock controls the vertical movement of the Girdraulic forks. There’s one half-width rear drum brake, mounted on the drive side without tommy-bars, and both wheels are of smaller diameter than on the Series Cs.

Although the swinging arm retains its rear stand lugs, the Series D models feature the most over-engineered centrestand ever to support a motorcycle. Its long hand-lever requires little effort to support the machine (and equally little to dislodge it by accident), curving neatly over the vented clutch cover when not in use.

The dual seat hinges forward and would normally lock down by means of a catch, operated through its pillion padding. However, these catches were flimsy and tended to break. There is space for a toolkit next to the oil filler cap beneath the seat. The oil tank bolts to the offside rear diagonal subframe tube and so pivots upwards with the rear cowling. Its filler neck contains a bleed screw for the rear chain oiler and like many owners, John has hung a small magnet from it to catch stray particles of swarf. Both pillion footrests bolt to the lower rear sub-frame tubes.

Three knurled alloy knobs retain each of the engine cowlings. Front crashbars are integral to the design, mounting side-wing extensions that are essential to direct cooling air behind the broad blade of the front mudguard and onto the engine. The motor itself is black only upon its exposed timing and primary cases, having die-cast crankcases and plain alloy cylinders.

Timing chest The black fuel tank is unadorned, the maker’s name being cast into the timing chest and primary case filler plug, and proclaimed upon transfers on the front mudguard and rear cowling.

John frequently undertakes short tours to Wales from his home in the Royal Forest of Dean, but is conscious of the need for security when leaving his valuable machine unattended. He has ridden his Black Prince as far afield as the VOC 2003 Canadian Rally, when the only mishap occurred during freight transport. “Someone’s footrest went through the fairing,” he recalls, ruefully.

Fortunately, glass fibre is easy to repair and the Vincent displays no signs of damage as I inspect it prior to a ride. The bike carries the usual signs of road use and John happily admits: “I’m not a concours man, but more of an oily rag man since I prefer riding bikes to polishing them. I certainly enjoy the fact that the Black Prince’s bodywork is easy to clean.”

Vincent Black Prince classic British motorcycleThe adoption of coil ignition on Series D models introduced an ignition key, which is obscured from the rider’s view by the oversized speedometer currently fitted. I apply the twin choke levers located on the right handlebar and the decompressor lever on the nearside. The knack of kick-starting these V-twins depends on following through with constant force the pedal swing from top dead centre of the rear cylinder.

First gear, engaged with a lift of my right boot, is extremely tall and I’m grateful for a grab-free action from the semi-servo clutch. The handlebars oscillate as I pull away, causing my knees, positioned halfway along the fuel tank as I peer over the black screen, to grip more tightly. As I accelerate briskly through the gears, I’m aware of reflected mechanical clatter from the engine, although the cowlings’ rubber-mounted attachment points seem to inhibit resonance successfully. The motor’s formidable torque compels me to brace against the narrow, low handlebars in this upright stance.

Handling in corners on the lanes around Goodrich Castle is surefooted, although the feeble brakes remain a curse of these high-performance models, even with the supportive metal plate fitted to the front linkage on Series Ds. Hence, on minor roads in particular, the wide spacing between gears means that I tend to hold on to the lower gears to induce the assistance of engine braking.

A blast down the dual-carriageway A40 towards Monmouth brings the engine on-cam, but prompts a persistent weave above 75mph, just as the bike is getting into its lengthy stride. I suspect the combination of an Avon SM front tyre and a well-worn TT100 rear, but must also question the fairing’s susceptibility to gusting side winds, blowing from the nearside front quarter.

Denied the opportunity to explore the upper reaches of the Black Prince’s performance with total confidence, I muse on the reaction of loyal Vincent customers, not to mention the wider motorcycling public, to full enclosure. Developed without the benefits of a wind tunnel, the new form was a brave attempt by Vincent to push motorcycling to a new level. The Motor Cycle duly reported favourable handling, noise levels and fuel consumption compared to a Series C twin. But the real point was, who on earth would want to cover it all up?

John knows that not everyone sees both style and substance in his heavily shrouded machine. “Unlike many Vincent purists, I actually like it,” he says. “I find it effortless at sustaining relatively high speeds while the extra sub-frame assemblies of the later models, with their improved seating comfort, make a real gentleman’s tourer. I’ve got wet enough racing sailing dinghies during the last 35 years to really appreciate that fairing!”

Vincent Black Prince classic British motorcycleThat proprietor Philip Vincent anticipated developments in weather protection, image, styling and suspension by a full quarter century is remarkable, but his insistence on low-volume exclusivity ultimately backfired in terms of high cost and limited popular appeal, just at a time when his company’s sales in the UK and America needed revival. Vincent tried to recapture lost ground by marketing ‘naked’ bikes when quality issues interrupted the supply of glass fibre, but it was too late. Barely more than 200 fully enclosed machines had been built by the time Vincent motorcycle manufacture ceased altogether, on 16 December 1955.

A fully enclosed Black Prince was the final motorcycle to be assembled and was labelled as such by factory staff, although a small number were subsequently built up from spares. Still extant, ‘The Last’ machine made £40,230 at the H&H auction in Cheltenham early this year (2007). Although doomed to a low-key and premature end to its campaign, the Black Prince’s distinctive armour retains the power to evoke former glory. bike

BSA Super Rocket

BSA Super Rocket

BSA Super Rocket

BSA’s well loved pre-unit twins culminated with the Rocket Gold Star, pretty much a hot Super Rocket twin engine in the Gold Star cycle parts. Overshadowed by its Triumph Bonneville counterpart, the Super Rocket was arguably as good a machine. Jim Reynolds takes a ride out on one, which is probably as good as it gets…

Bob Hall’s Super Rocket came from an impeccable source – a CBG Small Ad. “I saw the ad, called the chap and he said it was a really good one,” he remembers. “It was expensive though, but I went down to see it and took cash – got it for £500 less than he was asking.” Canny man, this Bob.

Nine years later the bike is as he wants it, and he’s out on the roads using it and getting some return on his investment, in the form of enjoyment. It wears Dunlop TT100 tyres and Bob reckons to get through two rear boots in a normal year, which does suggest an active life. I recently looked at a well known tyre website, and we’re talking £155 plus for a pair of sports-bike boots; that’s a price most classic riders can’t afford.

BSA Super RocketBob’s bikes started with a 50ccNSU `Quickly’ that was all his dad would let him have at 16. He took his test on it in his native Crosby, and was told to follow a figure-of-eight through the local streets until the examiner stepped out to simulate an emergency stop. He passed that bit, and the Highway Code questions, but failed on his riding. He was told: “Just because I can’t see you when you’re riding away from me, I can still hear you, and I didn’t hear the exhaust note change, which meant you weren’t slowing down and showing proper caution. I suggest you apply again and remember what I’ve said.” He did re-apply, remembered and did pass.

One day the ‘Man from the Pru’ (Prudential Insurance Co monthly premium collectors) mentioned a widow who wanted rid of her late husband’s old bike. Bob and his dad called round, to find a 1947 350cc Matchless G3L in original but shabby condition – a deal was done. The two of them brought it back to decent health and young Bob found himself the owner of his first serious motorcycle.

Bob then moved on to a 500cc G9, which he fitted with a Steib sidecar as an aid to staying upright on the Merseyside winter cobbles and tram lines. Later he changed allegiance to BSA’s Super Rocket, with a sidecar. The traditional move to cars followed and motorcycles faded from his life; gone but not forgotten.

Working life started in the police, but the need for more cash moved him to the building industry and then to the Post Office telephone service that morphed into British Telecom. He’s a long time Red Cross volunteer, driving the welfare ambulance for handicapped kids in his area; there’s no money in it, but the human reward is good. In an increasingly cynical world, it’s good to know that there are still people who simply wish to help others.

BSA Super RocketMaybe it was the millennium that stirred his memories into a serious yearning, but nine years ago Bob was browsing through Classic Bike Guide and spotted the 1961 Super Rocket. There was work done, like a later twin leading shoe front brake fitted and a Mikuni carburettor – the owner had commissioned the work to be done by a local engineer, as and when he could afford it and never bothered with bills. Bad move if you’re trying to sell a nice bike for top dollar. Bills to prove what you’ve had done and how much it all cost adds to the attraction of any bike. The result of no detailed work record did help to negotiate the lower price.
Back home, Bob decided to have everything checked out, for his own peace of mind. Having moved from Crosby to Wales, it made sense to visit BSA specialists SRM, at Abersystwyth. They undertook a thorough inspection and a careful rebuild, fitting Thunder Engineering conrods, insisted upon by Bob. “They’re beautifully made. SRM reckon they’re the Rolls-Royce of rods,” he explains. Produced to order by Steve Campbell, using 7075T6 spec aircraft alloy, they easily exceed the requirements of any road riding use. SRM then overhauled the magneto, adding an automatic advance/retard in place of the original manual control and setting the timing with 5⁄16in full advance rather than the standard 3⁄8in. They also sorted out a jet kit for the Mikuni and got that running sweetly, while an SRM touch is the conversion of the dynamo drive from chain to toothed belt, though Mr Lucas’s magneto still relies upon a chain to spin it round.

BSA Super RocketOut on the road, Bob found the gearbox slightly rough, so he and a mate stripped and rebuilt it, with new shafts and seals. Primary drive remains the standard simplex chain and the clutch is similarly as BSA built it; they also fitted taper roller bearings to the headstock. The twin leading shoe front brake drum was skimmed and the shoes fitted with green racing linings.

Paintwork was entrusted to Geoff Allison, over in Wisbech, a refugee from Manchester who used to trade as Miracle Finishers: “Some of the lads still call me Miracle Geoff,” he told us. “I remember doing that bike for a chap in Wales. It must be five years ago that I did it.” Well, five years on it’s a tribute to the man’s standards. “I don’t want to blow me trumpet, but I’ve been in the business 44 years, started with me dad when I was just 16,” Geoff explained.

It’s a handsome motorcycle with black cycle parts and red pressed steel components and I was glad to notice the Stadium rear view mirrors. “I didn’t have them at first, but one day a modern bike came past with a few inches gap and doing 30mph or more than me,” explained Bob. “I needed to see what was behind me.” That’s a logic against which it’s hard to argue.

Fired up at first kick, this is not a soft spoken motorcycle, thanks to pattern silencers that look the part but seem to lack a baffle or two; good audible warning of approach, I reckon. The brake and clutch levers are set up to suit Bob, but were too downward pointed for me, with no natural stretch of the fingers from grip to grasp. Also, moving the bike about before we headed out into the country, the front brake felt very grabby – mental note made to take care.
BSA Super Rocket classic motorcycle testOnce on the road the bike’s rideability shone through, that Mikuni helping low speed pull; the engine felt really smooth and responsive with the promise of a good spread of power. There’s nothing to add to the solid, predictable BSA chassis. The gearbox was as sweet as a nut, light in operation, with never a hint of a gear missed; excellent. The forks however were seriously under-damped, which combined with a snatching front brake could have made for a rough ride, but once the brake had warmed up its operation smoothed out and it performed progressively and strongly. The forks definitely didn’t like potholes.

Following snapper Wilkinson, with Bob navigating across rural Wales, I enjoyed a country cruise, our speed limited by the Welsh constabulary’s reputation for pointing cameras at passing bikes. They’ve had one £60 dip into my wallet and I don’t intend to open it to their greedy fingers again.

Bob led us up country to the winding climb of the Horseshoe Pass, where we stopped at the Ponderosa Café, to admire the view. As this is a family magazine, I won’t quote Bob’s words regarding the police habit of hovering in the valley at the bottom of the Horseshoe to film traffic unseen… Far better to tell anyone who’s never been up this stunning climb that a diversion from their journey is well worth the effort to stand on that hilltop and drink in the scenery. I ride a lot in Wales and I’ve never yet run out of new vistas to savour – look at Wilko’s pictures to get a hint of what the place offers.
BSA Super Rocket classic motorcycle restorationThe riding shots involved giving the Super Rocket some stick up and down a stretch of the Horseshoe on a quiet, sunny day. We used a succession of bends of varying tightness, and the flexibility of the Mikuni equipped engine was impressive. On one tight climbing bend I had initially dropped into second, but I realised even in third the bike would comfortably swoop through this right-hander and accelerate strongly up the following climb.

This is the first Mikuni equipped British bike I’ve ridden and I was most impressed. I remember the late Phil Allen explaining how tuneable they were, and here was proof. I can also recall an interview with Barry Johnson, long time Amal sales manager, who said that he would call on big customers like BSA every autumn to discuss the coming model year’s requirements, only to be told that they couldn’t possibly accept a price increase in the current market conditions. Mr Johnson, nobody’s fool, put it: “If you couldn’t put material price increases on the invoice, you took it out of the product.” Mikuni today seem to be in the happy position of selling to the classic bike market on quality and not subject to customers’ dictation.

Making progress with minimum waste of time (how the Institute of Advanced Motorists and their bike branch put it) up and down the Horseshoe on a noisy BSA could have been prize bait for officialdom, but in half an hour or so of enjoying myself there was no interruption. When I stopped, Bob thanked me for letting him hear his own bike at work, which made me realise that few of us get to hear the sound our classics emit and could see why mates swap bikes – the listening can be almost as good as the riding.

BSA Super RocketYou couldn’t describe the Super Rocket as an overlooked classic, because any member of the BSA A10 family line is going to be a good motorcycle, but with a genuine RGS now fetching five figures and the basic A10 to be found for £3000 for a good ‘un, the Rocket should be worth any serious rider’s attention. Its power unit is virtually the same as the RGS, (8:1 cr against the RGS’ 9:1) and a less generous selection of specification alternatives, but it’s damned nearly an RGS engine, housed in a capable rolling chassis with the added benefit of a comfortable riding position. A bike to live with very happily.

Is the A10 BSA’s best ever? The 650cc A10, better known by the more glamorous title Golden Flash, was launched at the 1949 Earls Court Show, the established 500cc A7’s big brother for the 1950 season. Engine dimensions of 70mm bore x 84mm stroke gave a capacity of 646cc and the bike was an instant success, used either to haul a sidecar or cover ground at speed. At 105mph, it was the fastest bike tested by the weeklyMotor Cycling that year. In 1953 came the Super Flash, aimed at the American market with its tweaked engine, a power output of 42bhp and a genuine top speed of 110mph. A serious piece of kit in 1953 and very rare today, but all that power in the old plunger sprung frame was pushing the envelope somewhat.

The line’s natural development came in 1954 with the swinging arm frame, and the rather dated Super Flash was joined and then superseded by the Road Rocket, using the new frame. That model in turn became obsolete when the Super Rocket arrived in 1958 and stayed in production until the pre-unit construction line expired in 1963. It has a slight power deficiency when set against the more glamorous Rocket Gold Star, but it’s much cheaper to buy and the chiropractor’s bills will be fewer. As a blend of traditional BSA sensible riding values and enough performance to easily lose your licence today, I would suggest it is the best of the Beesas. bike

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