Real Classic August 2017

BSA BANTAM  MORINI STRADA  NIMBUS 4  MATCHLESS X!

ISSUE 160  AUGUST 2017  £3.60

Running, Riding & Rebuilding RealClassic Motorcycles

WHAT LIES WITHIN

68 SUNBEAM S8.................................................6

NIMBUS MODEL C 750 ................................52

You know those technical tales where everything goes perfectly to plan, where the bike being fettled fires up first kick and heads for the horizon without a hitch? As Stuart Urquhart explains, this is not one of those stories…

Mike Salamon’s trade is rebuilding and restoring old motorcycles. So of course his hobby is also rebuilding and restoring old motorcycles. The Nimbus ohc inline four is one of the oddest he’s yet encountered…

BSA BANTAM ..............................................26

After months of preparation, Allen MacKinnon and his chums set off on their epic trek around Scotland, riding small capacity Britbikes to celebrate hitting the half-century

BSA’s Bantam was pretty long in the beak by the time it reached its D14/4 incarnation. But the Sports version of the 175 is one of the best featherweights, argues Frank Melling MORINI STRADA .........................................34

There has been an interloper at RCHQ Bude.

No, not a Royal Enfield Interloper, but an excitable little Italian. Rowena Hoseason and then Frank Westworth make the acquaintance of a certain Strada…

HONDA XBR500 ..........................................44

Honda’s 500 single is VMCC eligible, starts on the button and suits Richard Jones right down to its easy-clean Comstar wheels…

REALCLASSIC 160; PUBLISHED IN AUGUST 2017

RC REGULARS THE CONTENTS PAGE ....................................3

A remarkably eccentric collection of motorcycles. Something for everyone

TIDDLER TREK.............................................60

WE’VE GOT MAIL! ........................................16

Loads and loads and loads. Everyone loves reading letters: write more! Send more ancient pics!

WHITE HELMETS .........................................68

The Royal Signals Motorcycle Display Team trace their roots back to 1927, and their first public display of the ultimate in riding precision. 90 years later, Paul Miles says farewell to the White Helmets

EVENTS ........................................................78

MATCHLESS MODEL X ................................86

NEWS............................................................80

Sizzling roads, cloudless skies and heroic suntans await anyone riding to all these events Some things are happening, apparently

A very long time ago, Frank of this parish acquired a non-running Matchless Model X as a project. Inevitably, he did nothing with it.

Richard Negus is a man who can, and indeed did, and this is story…

READERS’FREE ADS ....................................82

The usual bizarre mixture of machinery.

TP has some chocs, however. National crisis averted … for now

BSA TRACKER PROJECT ..............................92

PUB TALK ...................................................102

Odgie gets completely hooked on the notion of ‘Go Fast, Turn Left’ which means he needs to build a suitable dirt-track scrambler. But before combat commences, let’s find out how he came to finish first on a different homebuilt Beesa, ahead of one Guy Martin…

PUB managed to get a few workshop tasks done in between the various events of the month – which included her annual Banbury battle with the Bollée – but progress remains minimal as it was too little spread over too many projects!

BMW R80.....................................................96

A ‘bargain’ eBay buy turned out to have more than minor mechanical gremlins but Stephen Herbert was not disheartened.

While the gearbox was being rebuilt he got stuck into the electrics and engine breather arrangements…

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TALES FROM THE SHED .............................108

All about the ones that got away. And one that did not!

TURNTO You won’tfindRealClassiconthe

P114

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shelvesin UKnewsagents.Ifyou wanttoenjoy regularRCreading then take outa subscriptionand join usin theRealClassicClub.Thatway, each issue costs just£2.50.Bargain!

4 I AUGUST 2017

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WHO’S DONE WHAT REALCLASSIC rattled into action this month, kickstarted by Rowena Hoseason and Frank Westworth of The Cosmic Bike Co Ltd, and Mike Baumber, Libby Fincham and whole Mortons production team at Horncastle Event reports and more bike features are posted throughout the month at www.Real-Classic. co.uk TRADE ADVERTISERS for the magazine or website should call Helen Martin on 01507 529574, email hrmartin@mortons.co.uk EDITORIAL ENQUIRIES should be sent to Frank@RealClassic.net or to PO Box 66, Bude EX23 9ZX. Please include an SAE if you want something returned or a personal reply SUBSCRIPTION INFO is on pg114. Call 01507 529529 to subscribe or renew or buy back issues SUBS QUERIES, late deliveries, or changes of address should be directed to 01507 529529, or email subscriptions@realclassic.net ALL MATERIAL in RealClassic is copyright its authors, so please contact us before reproducing anything. RealClassic is printed by William Gibbons & Sons of Wolverhampton. Our ISSN is 1742-2345.

THIS MONTH we’ve been reading TWO NIGHTS

by Kathy Reichs (by the numbers American thriller); THE ASHES OF BERLIN by Luke McCallin (simply brilliant WW2 mystery); A CLIMATE OF FEAR by Fred Vargas (the magnificent Commissaire Adamsberg returns!); THE BASTARD OF ISTANBUL by Elif Shafak (brilliant drama based around the Armenian genocide), and A CALAMITOUS CHINESE KILLING by Shamini Flint (An Indian detective investigates a murder in China, like they do – entertaining but not great) MEANWHILE AT THE MOVIES we had ‘so what?’ moments about both Baby Driver and Spiderman but adored Appleseed Alpha and Ghost In The Shell 2: Innocence, and chortled non-stop through Kingsman. Which just goes to show that (1) we’re strange, and (2) we need a holiday…

RealClassic is published monthly by MMG Ltd, PO Box 99, Horncastle, LN9 6LZ, UK. USA SUBSCRIPTIONS are $58 per year from Motorsport Publications LLC, 7164 Cty Rd N #441, Bancroft WI. 54921. Postmaster: Send USA address changes to RealClassic, Motorsport Publications LLC, 715-572-4595 chris@ classicbikebooks.com

FROM THE FRONT

I

’ve long been entertained by the notion of bucket shopping. Not shopping in a bucket or indeed for a bucket, but shopping for a bike on a personal bucket list – a list of things we simply must have before we – ah – kick the bucket. A charming thought, although I confess to a wry smile the first time I heard it. Which would have been in about 1970, I think.

And of course I always deny that someone so very serious as I am has such a trivial thing as a bucket list. I mean… if I want a bike – we are talking bikes here, not hovercraft, helicopters or rocket trips to Mars – and if I have the money, then I buy it.

Bucket list? I’ve ridden all the bikes I’m ever likely to want to ride. Apart from a Triumph Bonneville Bobber, that is. I seriously fancy a spin on one of those, just to provoke outrage at Bude Bike Night. And maybe a Harley Night Rod. With a name like that, they must be great.

But there are a few bikes I really, madly do fancy owning – which is not the same as riding. Argue among yourselves, all opinions welcome, please write them on a £10 and send it to TP, usual address. And there are a couple of projects I fancy too, which is not the same as wanting a bike just to own it or to ride it. Please use a different tenner for your thoughts on that, too. Maybe my ability to invent creative excuses for buying bikes is the reason there are so many of them in The Shed. I can usually dream up an excuse to get another, but I am utterly rubbish at explaining to myself why I should sell a few.

Hence the 650 BSA you might be able to read about in this month’s Shed tale. No more on that for the moment, not least because less than a fortnight after I was flushed with delight at acquiring a BSA I’ve wanted to acquire in exactly the condition I’ve acquired it, an AJS 31CSR appeared on eBay, in Cornwall, and in exactly the condition I want and of the exact year I want too! If there ever was an FW bucket list, then the 1966-67 AJS 31CSR is top of the list. I’ve occasionally seen

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them at shows and occasionally seen them offered for sale, but they have always been in utterly startling sparkling condition and entirely restored. This is no use to me. I want one to be as close as is possible to the state it was in when it left London a half century ago. Don’t care about whether it runs or is rusty. But I want the original factory stuff to be there still.

Which is exactly the condition of the Ajay which rolled up on eBay. And I even know the vendor! And he’s quite happy to hold it for me because the auction ends while we’re out of the country! And he’s happy to deliver it when we return!

So yes, a bucket list bike has appeared. I’ll no doubt fail to buy it and no doubt deeply regret this failure. But it does mean that there’s still at least one good two-wheeled reason to avoid kicking the bucket…

Ride safely Frank Westworth Frank@realclassic.net

THE NEXT ISSUE

RC161WILL BE PUBLISHED ON SEPTEMBER 4th, AND SHOULD REACH UK SUBSCRIBERS BY SEPTEMBER 8th

You know those technical tales where everything goes perfectly to plan, where the bike being fettled fires up first kick and heads for the horizon without a hitch? As Stuart Urquhart explains, this is not one of those stories‌ 6 I AUGUST 2017

Photos by Stuart Urquhart

SUNBEAM S8

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AUGUST 2017 I 7

S

unbeam were renowned for building quality push cycles long before their pre-war singles were celebrated for being light, fast and reliable. Good enough in fact to win four TTs between 1920 and 1929. But global recession and a second world war hit the British economy extremely hard, starving Sunbeam of much needed sales. Sunbeam struggled financially and were subsequently bought by Associated Motor Cycles. BSA then acquired Sunbeam in a move designed to compete favourably with the UK’s top cycle manufacturer of the time, Raleigh.

During the war years, Britain’s leading industrialists were given captured German war machinery, ranging from aircraft to motorcycles. As we know, BSA was presented with a DKW RT125 and their engineers came up with the extremely successful Bantam.

Another German motorcycle that influenced BSA was a captured BMW R75 – a machine that impressed BSA management, both in single and sidecar form.

8 I AUGUST 2017

It should have been the first of a new, modern range of BSA engines. An OHC, in-line twin, all fairly radical – for a motorcycle – engineering. How could it fail?

Inspired by the commercial potential of the BMW flat twin, BSA hired prominent motor engineer Erling Poppe to assist them in developing a new twin cylinder motorcycle.

The new twin was destined to become the flagship of BSA’s newly-acquired brand and, in deference to Sunbeam’s earlier vision of ‘the ultimate gentleman’s machine’, Poppe

and his development team set about creating the world’s most accomplished motorcycle.

For inspiration Poppe turned to BSA’s experimental Line Ahead Twin (LAT) engine.

Another departure was to replace BMW’s hypoid rear drive with a worm gear drive unit – a system already in production at BSA’s car division; Daimler and Lanchester. The experimental LAT engine and D&L’s worm

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SUNBEAM S8 Left: Right at the back, the drive is turned through a right angle to spin the wheel.

This is – again unusually for a motorcycle – by an underslung worm drive, which should be reliable but depends on the presence of oil…

Right: The engine’s left side is remarkable to anyone more familiar with more conventional British parallel twins. Great efforts had been made to present a radical and modern appearance, including hiding the spark plugs away behind a neat alloy cover. Fins galore – even the sump is finned!

gear drive were bolted to a BSA double cradle rigid frame along with BMWinfluenced telescopic forks, balloon tyres and heavily-valanced mudguards. In less than a year, Poppe’s Sunbeam prototype was ready for testing.

However Poppe’s new machine failed to impress BSA management. The LAT engine became crippled by excessive engine vibration and a severe torque reaction

within the worm drive ruined the prototype’s handling. Poppe managed to better his earlier machine by improving lubrication and detuning the engine. Thus in 1946 after a series of successful tests, BSA management approved the launch of the Sunbeam S7.

A consignment of S7s was shipped to South Africa’s police force, but several machines failed in service due to unforeseen mechanical breakdowns. As a consequence of negative publicity, BSA replaced Poppe with their head technical engineer, David Munro. Munro successfully resolved the S7’s mechanical woes by developing a unique engine rubber mounting system that resulted in a smooth and reliable machine – but unfortunately the Sunbeam’s handling continued to be criticised by motorcycling press of the time.

So Munro presented management with his plans for a sleeker and more conventional plunger frame model. The new model appeared in 1949, dubbed the S8, and was fitted with traditional style forks and slim profile wheels and tyres – components that were simply lifted from BSA’s A7 production line. The changes improved handling, making the S8 a more popular model than its predecessor. However the S7 continued as the ‘Sunbeam De-luxe’ and benefitted from many of the S8’s updates. The S7 was also treated to a new Mist Green paint scheme, while the S8 was available in conventional Black or Polychromatic Gun Metal Grey.

But sales success eluded both models, due in part to a lack of development by BSA management distracted by the success of their A and B series models. Both Sunbeam models continued unchanged into the mid1950s, before they were quietly dropped.

Today Sunbeams enjoy a loyal following, and this is reflected in high premiums for well-sorted models. Stewart Engineering is

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the accepted and well-regarded Sunbeam specialist, and the firm manufactures new parts and stores much of the UK’s remaining stock of ex-factory spares.

I was introduced to RC member Iain’s 1952 Sunbeam S8 when I scribbled a report about his TR5 Trophy. Iain’s Sunbeam was incapacitated by a ridiculously stiff clutch. It had also lost its spark, so owner Iain had no choice but to relegate the coil-ignition and battery dependent machine to its sickbed.

Unfortunately months passed before I could uplift and service Iain’s Sunbeam, by which time it was most definitely lifeless. When I turned on the ignition key the warning lights flickered and died. A traditional spark plug test also drew a blank and, much as expected, my voltmeter recorded an insignificant 4.2V from the Sunbeam’s ailing battery. It was time for a check-up...

My test procedure is usually ticked-off in the following order: Points; tappets; ignition timing; carburettor; fuel; fluids; battery; electrics; chains; clutch; cables; brakes and tyres. Of course any test procedure is open to change depending on what faults are known, or which turn up during an investigation.

First item on my S8 fault-finding mission was the grouchy clutch. My hunch was that the heavy action was simply down to poor cable routing, but closer inspection turned up several broken inner wires and a serious lack of cable lubrication. The cable was also fully extended with no adjustment left. Ever helpful, Stewarts kindly advised that if I was replacing the cable I should also consider renewing the clutch thrust race and pushrod collar along with its separate hardened cap. Important parts, I was assured, that are inexpensive to replace but are prone to wear if not routinely serviced. The clutch parts were ordered along with a new pushrod, clutch arm and spark plugs.

AUGUST 2017 I 9

Next it was the broken speedometer’s turn.

I removed the speedometer cable from its drive head to check that the inner winding was rotating freely. As the S8 speedometer is driven by the gearbox, this is easily checked by first removing the spark plugs and then spinning the rear wheel in gear. The drive wire appeared to be rotating fine, but when I ‘nipped’ it with my fingers, it immediately stopped. This of course should not be possible and pointed to a damaged inner, or possibly one that had jumped free from its drive spindle.

Removal of the speedometer cable and its related gearbox drive mechanism (located on top of the gearbox) is only possible by first removing the seat and RHS toolbox – a tedious task. To further complicate removal this toolbox houses a rat’s nest of electronics and the speedometer cable – which is unhelpfully routed through the centre of said toolbox.

Then the battery and left side toolbox must also be removed to access fixings located behind the battery, as both these items ride piggy-back

Above & right: Beautifully cut-away engine displays some of its unusual innards. As was common car practice at the time, both intake and exhaust functions are carried out on the same side of the cylinder head, although there was a later experimental crossflow development, it never reached production Right: The search for sophistication included mounting a shaft final drive, in this case with the shaft itself running in full view

SUNBEAM S8

style on the right hand toolbox. It’s a bit like dissecting a chicken to fry an egg!

After completing this onerous task, the gearbox drive unit can then be removed by unscrewing two bolts. Examination revealed that the unit’s female drive spindle had cracked to the extent that it could no longer grip the inner speedometer cable: problem solved! A phone call to Stewart Engineering confirmed that NOS geaarbox drive units are available off the shelf..

Several days later the Sunbeam waas fitted with a new clutch cable. But before the DIY mechanic can insert a new thrustt race into the gearbox end cover he must first remove the clutch arm. Now this, it must be said, is a contortionist’s job. Work space on the drive side is severely limited due to the clutch arm being located behind the gearbox and immediately adjacent to o the shaft drive’s housing. Primary side acccess isn’t much better either, as the clutch h arm is hidden behind a THIRD toolbox and its adjacent horn – both must be removved

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before you can gain access to the arm itself.

However once the arm is removed and you attempt to extract the race and cup, your hand becomes jammed tight against the rear mudguard. It’s a tough job! Well worth the effort however, as with the new parts in place the clutch action was much improved.

Thankfully, removing the S8’s accessible and ‘hanging-in-the-wind’ carburettor was

the antithesis of the clutch repair. But my jubilation was cut short when I discovered the carburettor was full of grime and I was forced into flushing out the petrol tank. The air filter was also in a grim state and looked perfectly capable of allowing all and sundry unrestricted passage into the bowels of the engine. A shrewd guess was that the filter had not been replaced since Bill Haley belted out Rock Around the Clock.

Wide and comfortable bars and conventional controls.

The pilot soon observes that the (repaired) speedo is flanked by a pair of unfamiliar warning lights, actually taken from dashboards of British-built cars of the time rather than the Lucas motorcycle parts bin

AUGUST 2017 I 11

After the carb problems were addressed, next up was fitting the recharged battery and testing for an ignition spark. This time when I turned the ignition key I was instantaneously dazzled by the ignition (red) and oil pressure (green) lights flashing on. Holding my breath for a second time I earthed a new spark plug against the cylinder head and gave the kickstart a few prods. But there was no hint of sparks from either cylinder. This can be caused by a multitude of problems, each of which the DIY mechanic must eliminate in turn. True gumshoe work – it is very gratifying whe en you finaallyy traace the e faaultt.

The True Detective can rule out a brand new plug (or if in doubt, simply test on another working motorcycle). Similarly, as Iain’s Sunbeam was running beforehand, I could rule out the coil in favour of the next likely source of lost ignition sparks – the points. These are located inside the

distributor, which on the S8 is mounted topside rear of the engine. When I removed the distributor cap to access the points, I inadvertently stumbled across the problem when the coil-to-cap HT lead fell away in my hand. Thus it was easy to deduce that the distributor was being starved of power from the coil. And if proof were needed, when I looked inside the distributor cap, a little grub screw that holds the coil’s HT lead in place was missing. Once I’d trimmed and refitted a new section of HT lead and a replacement gru ub scre ew,, I popped the e disstrib buto or cap back on and retested the plugs. The reward was a nice juicy spark from both plugs. Hurrah!

Sparking restored, I reset the points gap to the recommended 12 thou. After disturbing the points it is then necessary to check the ignition timing at TDC when

the S8’s points should just be opening. This reading must be taken on the compression stroke immediately after the inlet valve has closed and the piston is rising. I use a 0.015 thou feeler gauge (as opposed to the customary fag paper or light bulb) to determine when the points begin to open.

The timing proved to be spot on (but best to check twice – I do!).

Many riders consider that both the looks and the comfort of the Sunbeam are improved by fi fittting a solo sprung saddle, for which the mountings are present.

And the S8 was graced by an unusual cast alloy silencer, unlike the S7

CURRENT AFFAIRS Left: Down by the rider’s left foot lives a second toolbox and the rear brake’s crossover linkage

Sparks are supplied by a car-type distributor driven from the rear of the overhead camshaft

12 I AUGUST 2017

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