Road Test: Triumph 500 CD

1932 Triumph 500 CD

The motorcycling world was a very different place in 1931. Competition machines back then bore a close resemblance to the sort of machine that could be seen propped up against countless factory walls in the week. And with good reason too. Most of those machines were one and the same before the encroachment of the age of specialisation. Even so, most factories were waking up to the fact that some riders wanted just a little bit more than the standard ride to work offerings – and might even be prepared to pay for it. Certainly Triumph seemed to have this in mind when they announced their line up for the 1932 season in November 1931.

Although both the 350cc Model CA and the 500cc CD cost just £2 more than their roadster counterparts (at £43 17s and £48 17s respectively), there were significant differences. The competition models had polished ports, high lift cams and stronger valve springs and compression ratios were raised to 6.3:1 on the 350 and 6:1 on the 500cc CD. A racing type Bowden carburettor, upswept exhausts, roller bearings on the rockers, adjustable footrests and strengthened handlebars – available in a choice of ‘clean’ (with concealed control cables) or ‘sports’ (with exposed cables) – added to the list. A sturdy steel shield around the exposed front section of the protruding sump, together with Dunlop competition tyres, a special head steady and foot gear change, completed the list of extras you got for your two quid. The move towards purpose built competition machinery had begun.

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New breed of machine
The fact that the CD and its little brother the CA were among the first of a new breed of machine is part of the appeal to owner Alan Berry. He first saw the machine about three and a half years ago when fellow enthusiast Donald Ideson owned it. Alan had gone to see Donald about a Triumph Tiger 80 – which he subsequently bought – and the earlier single caught his eye. Donald, a former pattern maker from Skipton, Yorkshire had been equally smitten by the Triumph’s purposeful lines and intrigued by its rarity. So much so, in fact, that he had spent five years collecting parts at autojumbles and doing bits and pieces to the machine as and when time and finances permitted.

Triumph 500 CD classic motorcycle road testThe major stumbling block for Donald was the oil pump. The plunger type pump (which employed a steel rather than bronze plunger as on the road models) is driven off the timing side crankshaft main shaft, at one eighth engine speed, via a spiral pinion. On rotation, the pump body exposes a port to a feed duct from the oil reservoir and draws in oil by means of the downward action of a plunger operated by a cam inside the pump body. The lower (and larger diameter) section of the plunger acts as the scavenge side of the pump and returns oil to the top of the oil tank through a similar timed port arrangement. The oil tank itself is an integral casting with the crankcases, protruding from them at the front of the engine. With the original pump beyond repair, a new one cost a whopping £260 to re-manufacture. Eventually, Donald got to the point where he could take no more and the partly completed project was sold to Alan.

Alan says the CD was fairly complete and the restoration of it about two thirds finished. “There was no exhaust pipe,” he says “and various bits and bobs were either part-finished or missing. But everything that Donald had done was spot-on as you would expect from a man with his background.” Alan completed the chainguard, which Donald had started, fabricated a wiring loom and commissioned a new exhaust pipe. Both the magneto and dynamo needed re-conditioning and Alan made a rear stand too. The great thing was though, that so many of the original parts were still present – and therefore correct.

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“Even the control levers and cables were there, so I didn’t need to scour the country for the right ones,” recalls Alan incredulously. “They have the ‘Bowden’ name embossed on them, which is a nice touch.” A +30 thou’ piston resides in the barrel at present, but it has no scraper ring and the engine burns a fair bit of oil as a result. Alan plans to replace this with a Tiger 90 piston with an oil control ring to solve the problem once and for all.

The reason why he didn’t do this, as well as a few other modifications and improvements he has in the pipeline, is that he wanted to get the Model CD ready in time for the VMCC Manx Rally in June 1999. Ready it was – and it exceeded even Alan’s expectations by winning its class in the concours display too. “The best thing is, though,” says Alan, who took his 14-year-old son Mark over to the Island with him, “that it never missed a beat. We did the lot – a lap of the TT circuit and everything and had no trouble at all.”

New Model CD
In the Island, Alan met Maurice Butler, who had owned a new Model CD in 1932. “His mother bought it for him when he was 16 apparently!” says Alan with some disbelief. Maurice lent Alan a photograph of the machine, taken shortly after he got it, which Alan has had enlarged and which has proved a most useful reference. “It’s a pity the picture is only black and white though,” says Alan. “The most difficult thing to discover has been the correct colour scheme for the petrol tank,” he continues. “At the moment, I’ve done it how I think it should be, but it’s hard to tell from the photographs whether parts of the finish should be chrome or paint.” The machine’s previous owner, Donald Ideson, had similar concerns over the correct finish and entered into protracted correspondence with the Triumph Owners Club 1923-33 specialist Peter Cornelius on the subject. Peter was in the same boat as everyone else in having to rely on black and white representations of colours and, though he was able to offer Donald some guidance, even he was unable to offer a definitive solution to the colour problem. For the record, Motor Cycling for 11 November 1931 merely states that; “…the machines are finished in black, but without extra charge, they may be obtained with either grey, red, blue or green as the predominating shades. If it is wished, chromium-plated tanks can be had, but an extra charge is made for this finish.” That’s all very well, but there is no detail of exactly where these colours are applied, so if anyone can shed any light on this, Alan would be most grateful.

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Triumph 500 CD classic motorcycle road testI’ve ridden Alan Berry’s machines before – we tested his Triumph T100 race replica in the May 1999 issue – and I’ve seen the way he operates in the workshop. There are no half measures and, as Alan is a keen rider himself, all his motorcycles are set up really well. The T100 was an absolute delight, so I was looking forward to riding something a little different from the same stable.

Before I arrived at Alan’s house on a cold, grey and miserable November day, I had never set eyes on a Triumph CD, but as soon as I clap eyes on the handsome 500cc single, I know I am in for a treat. I’ve got a soft spot for Thirties’ singles anyway but even without that weakness, I would defy anyone to remain unmoved by the lean and purposeful CD. By the Thirties, motorcycles had progressed from their motorised bicycle roots, into what is essentially their modern form. If the Twenties was a decade of change and innovation, then the Thirties was an era in which many of these developments enjoyed their full flowering. It truly was a golden age, when design and engineering combined in a happy confluence of form and function.

Some people may think that practical machinery only arrived on the scene in the Fifties. In fact, a well prepared Thirties single makes an eminently rideable classic today. Foot gear changes gained in popularity and efficiency throughout the decade and internal expanding shoe brakes rapidly became the norm. Add a lively ohv engine, light weight and electric lighting into the equation and you have the recipe for enjoyable classic motorcycling.

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Enough of the lecturing though. What is the CD like on the roads of today? Looking out of Alan’s garage window as I change into my riding gear, I can sense that the Triumph will need to be something special to make riding on such a cold and miserable day a pleasure. True, the cheerful bright red paintwork and gleaming black enamel on the machine lift the spirits to an extent. But with the roads greasy from intermittent rain and the prospect of a film of mud from various farm vehicles I have observed plying their trade on the way up to Alan’s South Yorkshire home, the CD has got a lot to do.

Road conditions
In fact, the rigid framed single turns out to be an almost ideal tool for the road conditions. If you think about it, it should be no surprise. After all, what are the ideal qualities of a machine you would want to ride in cold, damp conditions on a slippery, unfamiliar road? Light weight? Certainly the CD can oblige here and with the added attraction of a particularly low centre of gravity, partly afforded by its mere 4½in of ground clearance and low seat height. Efficient and progressive brakes? Here again, the internal expanding shoe rear and expanding ring front, brakes are perfect for the job, providing ample retardation with adequate feel when properly set up. Naturally you would not want to be struggling with a hand gear change on slippery surfaces, so the four-speed foot change on the CD is a blessing. And the 493cc ohv single-cylinder engine is both docile enough to tip toe along in the worst conditions, while having the punchy snap of a sporting unit to enjoy when the coast is clear.

All these features conspire to make my outing on Alan’s CD a real pleasure despite the weather. While photographer Nigel Clark grumbles and gripes about the poor light doing strange things to his exposure, I am enjoying myself immensely. I have more or less got the road to myself (apart from a grim faced Clark following me down narrow mud spattered lanes in his car) as we search for a suitable location for photographs.

Initially, I find it very difficult to make a clean gear change between first and second ratios. It turns out that Alan himself is none too impressed with the gear selection and plans a strip down of the gearbox to rectify the situation. And the brakes – particularly the front one – which in principle should be well up to the job, do not seem to offer much in the way of real stopping power. Perhaps I’m expecting too much, but Alan is, once again, one step ahead of me, confirming their lack of bite and announcing his intention to skim the drums and machine the linings to suit. That should do it.

Triumph 500 CD classic motorcycle road testAs I get used to the CD though, even these minor criticisms seem to fade to the back of my mind. In the real world, away from the cut and thrust of town traffic, the back brake can be allied to the effective engine braking to provide adequate retardation and I seem to get more adept at swapping cogs too. The low slung machine inspires such confidence and the motor pulls so strongly out of tight bends that I am easily able to pull away from the pursuing Mr Clark. That’s a fairly impressive feat for a near 70-year-old motorcycle.

As I hand the CD back to Alan, I can’t help but reflect that it sometimes seems as if as much real progress in motorcycle design and development as we think has taken place since the Thirties. Certainly tyres, brakes and suspension have come on, but even then you have to consider whether early, un-damped telescopic forks were much of an improvement on well sorted girders.

What I am sure of is that a good 500cc single of the Thirties has a lot going for it. Granted, Alan’s Triumph CD is a rare model and as such would command a premium price, but in many ways it is a typical machine of its period and there are many more affordable models of similar vintage. The virtues of light weight, a low centre of gravity, excellent fuel economy, simplicity and enough performance to excite without intimidating are surely the essence of motorcycling. And the benefits of sound engineering in an era before automated production lines begat the end of hand-finished machinery, are exemplified by machines like the Triumph CD. 

Sure, a Sixties twin will get you there quicker but, on a twisty cross-country route on narrow roads, it won’t be that much quicker. Anyway, the joy of classic motorcycling is surely in the travelling rather than the getting there. If that’s true, Alan Berry’s Triumph CD will be providing him with riding pleasure for many years to come. bike

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