June’s Classic Bike is a bumper 132-page issue celebrating 40 years of Honda’s benchmark VFR – the bike that rebuilt the Japanese manufacturer’s reputation.

There’s the story of the VFR750F and its trademark V4 engine with gear-driven cams, plus how a Honda UK boss saved the model from being cancelled during development. We ride a superbly restored VFR400R and a professor of engines explains why the RC30 is such a special creation.

With the Isle of Man TT about to rev into action, there’s also a series of amazing tales from different eras of the legendary annual road races, including the story of restoring a record-breaking Gus Khun Seeley Commando. And there’s the story of a bought-unseen 1951 AJS being ridden the length of France, a German museum full of fascinating machinery, plus a 23-page workshop section stuffed full of projects, advice and tinkering…

The June issue of Classic Bike is out now at newsagents, or why not subscribe today and enjoy your first 3 issues for just £5!

RICK RIDES

Last month Rick rode a Laverda Jota and wondered if Triumph’s Trident could ever have been as good. This month he finds out…

Words RICK PARKINGTON Photography GARY MARGERUM

History is filled with coulda-beens. Triumph originally conceived their three-cylinder Trident in 1965, but production was delayed and by the time it arrived it was soon overshadowed by Honda’s CB750. Last month I rode a Laverda Jota and felt it made more sense than a Triumph Trident, but was I being unfair? I decided to find out more – and I knew just the bike to ride.

The yellow number boards on this unrestored T150V reveal its history. This is a former Isle of Man TT marshals’ bike, meaning that while it looks broadly standard, beneath the surface it is not. Five triples were factory-prepared for marshalling and, although not race tuned, the attention lavished upon them in the experimental department gave them a bit extra that might make me view my judgement a little differently.

Threading out of owner Graham’s drive on the Trident I feel just a tiny bit unsteady, but this immediately disappears once I’m on the tarmac. The Trident is extremely stable and instantly reminds me of the Jota I rode last month. It’s not at all like its closer relative, my own 1968 Triumph 650. My bike handles very well, but feels more spontaneous, like a carefree puppy, darting about ably without losing its footing. The Trident has more of the Jota’s purposeful long-wheelbase running-on-rails feel, though seems slightly less determined. I’d guess the T150 would be easier to budge off its line if needed, as though it has a sprinkle of the nimble 650’s character in the mix.

This triple has a five-speed gearbox. Supposedly they’re standard ratios – they feel closer than my old 750 Bonneville, but then this is a very different bike.

‘I take it to 7500rpm with no sign of power falling off’

First isn’t particularly high, but you still have to think what you’re doing when pulling away. I’ve been warned that the bike is a bit ‘cammy’ and you can quickly tell it’s not developing much in the lower rev range – especially with the engine cold – but I soon get used to it. In fact, it’s surprisingly good at urban speed in top gear – smooth and quite docile. It feels as though it’s revving unexpectedly high in top at just 40mph, but a glance at the rev counter proves that’s an illusion. We’re not yet at 3000rpm, however on the triples the extra piston provides an additional bang over a twin’s steady drumbeat that makes it sound busier, as well as producing that strangely melodic rasping gurgle I’m enjoying through the twin ‘raygun’ silencers.

Once past the derestriction signs and with the engine warm, I open her up. At 3000rpm in top gear not much happens, and I have to drop twice to third before it really picks up. But from 4000rpm the Trident streaks away like a startled hare, the gurgle overtaken by that legendary three-cylinder howl that sounds more enraged and demented the longer you hold the throttle open. The gears feel even closer now and chime in perfectly, the Triumph picking up cleanly and pulling very hard.

You can’t really say the power has a ‘band’ as such – it’s more like a prairie stretching to a far horizon. Searing up through the lower gears, I take it up to 7500 with no sign of the power falling off – and only stop there because seeing the needle that high on a tacho with no redline reminds me that I don’t actually know the safe limit. The engine is no help at all – it seems to be enjoying itself just as much as me. (I later learn 8000rpm is probably about it.)

This is a quick machine with very impressive acceleration for a British bike, and an exhilarating experience that is well matched by the handling. At speed the Trident is rock solid, yet easy to switch back and forth. The only niggle is at low speed when, sitting up no-hands to take the weight off my wrists, the ’bars set up a tiny waggle. I think back to that slight unsteadiness I felt when first setting out and wonder if, given the sensation of purpose about the bike, the balance had been shifted slightly to offset the effect of the dropped handlebars. The owner says he’s noticed it too, but thinks it may be down to the forks. They’re later than the bike – but original to its TT career because these marshal bikes were developed over the years, remaining in use up until 1976, by which time the disc-brake T140 Bonneville was in production.

“I was looking for a race bike at the time,” says Graham, “and my mate Rob Prior tipped me off about the Tridents. He knew about Triumphs and said they’d be good. So, I went halves with my sponsor and bought the last one left. Factory-team mechanic Steve Brown rebuilt the engine for me, and I set about turning it into a Slippery Sam lookalike. I raced it for three years from 1978, but had a few problems so I retired it in ’81 because parts were getting scarce.

CUE 763J was registered on June 1, 1971 and is the only one of the marshals’ bikes with a five-speed gearbox, a preference of rider Jack Harding. By 1975 the triples were for sale, due to be replaced by Hondas. Factory development boss Doug Hele bought one and, anxious to see the marshals remain on Triumphs, North London dealer Bill Slocombe bought the other four. They were back at the TT for 1976, but Slocombe’s offered them for sale after the races, priced at £750 apiece.

“Ten years later, I read an article about the marshals’ bikes in Classic Bike and realised it was a bit too special to sit in the back of the garage, so I dragged it out. Being a bit of a hoarder, I’d kept all the bits I took off, so I sold the Slippery Sam parts and put the money toward getting someone to restore it. But the guy who took it on had a change of circumstance and had to give it back before doing the job – and now I’m really glad because I appreciate it more as it is. Even those Shell stickers on the tank are original – I panic about spilling fuel on them every time I fill the tank.”

Mods on the marshals’ bikes included holes machined in the rear brake plate for extra cooling
Being virtually a race bike, many of the Trident’s exterior modifications are more function than form. Holes for the rearset footrests have been drilled in the rear gusset plates and the kick and gear pedal plating is still ‘blued’ from where the Meriden gas torch was used to bend them to suit. The disc front brake required a change of handlebar lever to the T140 Bonneville master cylinder, with built-in switchgear – but the electrics have been removed and the holes filled with body filler. “That’s all how it came,” says Graham. “And you see those handlebars?” I nod, glancing at the scruffy Ace bars, cut about and welded. “I was lucky enough to meet Ron Barrett, who put the bikes together at Meriden. He looked over my bike and said: ‘I did that!’ – he’d had to cut the ’bars to fit them through the P-clamps that bolt to the fork yoke and then weld them back together. He also recalled machining holes in the rear brake plate and back of the clutch housing for extra cooling, and fitting a Bonneville rear mudguard with the rear numberplate bolts done up with the nuts on the outside to avoid them digging the tyre on bumps.”

How many restorers would change these homespun details without ever realising they were actually factory mods and part of the bike’s history?

So many classics have been upgraded in various ways that it’s always interesting to ride ones that are stuck in a time warp, still largely as the factory made them. Like this Trident, they’re often much better than you’d expect. I’m very impressed with the power and smoothness – and of course that lovely howl – and can easily see why the Trident was a necessary step up for anyone wanting to stick with Triumph in the 1970s.

But in this case, there’s another dimension. Put together by Triumph’s top people, the marshals’ triples are a much better representation of what the designer was trying to achieve than the luck-of-the-draw selection found in a showroom. I now suspect that by design, the Trident was much closer to the Jota than I thought. The fastest of the five Tridents was timed at 135mph, ahead of contemporary Japanese 750s and not far behind the 1000cc Laverda.

‘It has more of the Jota’s purposeful running-on-rails feel’

People have said: ‘If only the marshals’ Tridents had gone into production’, but the problem wasn’t the design – it was the material. If the Trident had been made in the Honda factory, then maybe – but it was impossible to achieve Japanese levels of accuracy and consistency at Meriden, a factory from a bygone era. And the expert attention to detail that made these bikes work could never be viable for a production machine.

And that’s why, for the last 50 years, so many owners and specialists have worked on refining the triples. The design was worth the effort, and the potential was clearly there for a world-beating road bike. How sad that, except for these five marshals’ bikes, the factory was unable to exploit it.

SPECIFICATION: 1971 TRIUMPH TRIDENT MARSHALS’ SPECIAL
ENGINE/TRANSMISSION
Type Air-cooled pushrod three-cylinder four-stroke
Dimensions 67 x 70mm
Capacity 740cc
Power 60bhp at 7500rpm
Compression ratio 9.5:1
Carburation 3 x Amal Concentric 627
Clutch Diaphragm-spring dry single plate
Gearbox Five speed
CHASSIS
Frame Steel tubular cradle
Front suspension Telescopic forks with alloy sliders
Rear suspension Swingarm with twin adjustable shock absorbers
Brakes Front: Single Lockheed disc and opposed-piston caliper. Rear: Single 7in drum, drilled for cooling
Wheels Spoked with Borrani flanged aluminium rims
Tyres Front: 90/90 x 19. Rear: 120/90 x 18
DIMENSIONS
Wheelbase 58in (1473mm)
Weight 468 lb (212kg)
Performance 135mph

The marshals’ machines

Marshals’ bikes make a great advert for manufacturers. They look like standard models, but need to be reliable and fast enough to get anywhere they are needed quickly and without getting in the way of the racing. There’s obvious sales potential in having one of your production bikes out there mixing it with the racers – which, after all, is where 90% of the spectators want to be. So a marshals’ bike had to be very well prepared – not in race tune, but just about as good as a standard bike could get.

This Trident was one of five used by marshals between 1969 and 1976, registered CUE 762J, CUE 763J, UUE 14G, UUE 15G and VWD 587H. They were built in the experimental department by Ron Barrett, who later claimed the only non-Triumph engine parts fitted were the US-made S&W valve springs. But he put great effort into blueprinting the engines: oil pipes were opened up to cope with possible high-speed cold starts, cylinder heads were carefully gas-flowed, valve timing and primary drive alignment perfected, and he recalled picking through conrods to find three of precisely matching weight to achieve the best possible balance.

Further modifications were made to suit the requirements of the marshals who rode them. Our test bike was the only one to be fitted with a five-speed gearbox (the rest had close-ratio four-speeders) and also a single front disc. One of the other bikes had twin discs, but the rest stuck with Fontana eight-leading-shoe racing brakes, fitted after the standard twin-leading-shoe brake proved inadequate. Ron Barrett told the owner the disc was a blessing: “You’d get the Fontana set up perfectly, but every few laps it needed doing all over again!”

According to the DVLA website, all five of the marshals’ bikes still exist. CUE 762J was in fact a BSA Rocket 3, built in police spec as part of an export order. Accidental damage in the factory saw it repurposed and disguised as a Triumph. After being sold to Doug Hele, it was raced by his son and benefited from extensive modifications, including a works racing frame.

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AJS ADVENTURE

Buy a 1951 AJS Model 18S unseen and ride it 750 miles to the French Riviera? Sounds like a plan…

Words and photography CLIFFORD DENN

There’s something quietly heroic about pointing an old Brit single towards the horizon and seeing how far it’ll carry you. No chase van, no illusions of easy miles. Just a 1951 AJS Model 18S thumping steadily beneath you conjuring the faint sense that – despite seven decades of technological progress – this is still what real motorcycling feels like.

Most long-distance motorcycle adventures begin with a plan. Mine is to set off from Wimborne, Dorset, for my home in Valbonne, in the south of France, via non-motorway roads and the resolute belief that 63-year-old me and a 75-year-old AJS still have the stamina for a proper continental ride.

I’m also carrying the Malawi flag on the side panels. It’s where, aged 15, I rode a motorcycle for the first time – a very bodged 1955 350cc AJS 16S that my father salvaged from ‘the bush’. It was given to my younger brother Andrew, who wanted a motorcycle, but also – to my dad’s despair – considered a hammer suitable for all repairs and believed bent nails were perfectly acceptable substitutes for split pins.

I remember my first ride on it. The slow, relaxed thump of its single cylinder, the smell of petrol and hot oil, the carb inhaling warm African air. Although it seems like a bicycle by modern standards, I thought it was huge – I can recall ‘manhandling’ it around Malawi’s dusty roads.

It inspired me to buy an AJS 650 CSR when I was 19, which I still own. But I’ve always wanted another big old Brit single. So, as a tribute to the memory of my parents and those halcyon Malawi days, I use some of my inheritance to buy another – a proper pre-unit AJS like the one in Malawi, but this time a 500 instead of a 350.

Bought as (un)seen

An advert appears for a Model 18S that’s essentially a 1951 AJS 500cc engine stuffed into a 1953 Matchless 350 frame. A true British parts bin romance. The seller assures me it’s a good bike and that if he were 10 years younger, he’d ride it to the South of France. There’s just one issue – the seller lives in Barnard Castle and

I’m unable to get there to see the bike in person. But videos show it doing 65mph with something resembling confidence, so I agree to buy it on the condition a base gasket oil leak is fixed.

The bike is shipped from Barnard Castle to Wimborne, to my old Malawi schoolmate Gordon, known universally as Cochon (French for pig) – a nickname my mother gave him because he’d happily eat anything. A trait that, in the 1970s, was both impressive and alarming. Cochon runs Bugad Classic Bikes and Feked Classic Bike Parts, and kindly offers to check the bike over before I set off.

Then reality intervenes. After a quick test ride, the bike dumps all its gearbox oil overnight. What was supposed to be a simple check-over becomes a major effort on Cochon’s part, and he has no hesitation informing me he has enough bikes of his own to fix without finding the time to work on my purchase, which he christens ‘The Turd’. Despite this, and the costs, we laugh so much while working on the bike. The name sticks, too.

Reassembled, the bike leaks a single drop of oil overnight. A miracle. Or perhaps a sign it hadn’t woken up yet. Regardless, I’m confident enough to book the ferry. But it’s late October – so I’ve missed the warm weather. I’m destined to ride a wet Turd all the way through France...

My wife Izzy, brother Andrew and I spend a few days with Cochon and his partner Victoria, fuelled by nostalgia and bottles of Chibuku Shake Shake, the legendary Malawian ‘beer’ with the consistency of yoghurt and the taste of… well, you know. A final test ride on the Ajay reveals a suicidal mirror and a speedo rim that tries to escape above 40mph – both are replaced. Then we find ourselves flying around Dorset in Cochon and Victoria’s immaculate 1942 Boeing Stearman biplane. The bike, pictured next to the plane, looks almost dignified.

Ready for the off

Equipped with tools, a tow rope (for “when we break down, not if”, Cochon reminds me, as he sketches how the towing works from a low centre of gravity with rope around the footpegs) and high hopes, we set off for the ferry at Portsmouth. Cochon acts as support vehicle for this first real test.

The AJS crackles out of Wimborne with the faint scent of petrol and warm oil, producing a sound typical of many 500cc Brit singles when pulling away at dawn: one of half-optimism, half-defiance. Skirting showers towards Portsmouth, every noise and smell is suspect – but we make the 50 miles to the ferry. It’s a good sign.

As I see the back of Cochon’s BMW leave me in an empty car park near the ferry terminal, it sinks in: the AJS and I only have each other now. A deep sense of fear takes over as I realise we need to fend for ourselves. There’s a rainbow over my departing friend – I take it as a message that we will be OK. Waiting to board the ferry, other bikers and the general public saunter over to look at the AJS – they all nod, look at each other and smile politely when I tell them we’re heading for the South of France.

Boarding is smooth, and by midnight the ferry docks in Caen. With trepidation I kick over the AJS, but it barks into life on the third kick. The yellow street lights reflect off the wet road as I show my passport to the Douane, then we really are on our own as we roll along a road in the middle of the night without a car or another human in sight. The engine enjoys the cool air and everything works fine – I start to feel a bond with this machine for the first time. I check into the hotel in Caen with covered parking at around 1:30am and sleep well ahead of the four-day ride to Valbonne.

Ooh la-Loire

The morning is a biting 3°C. But no time to complain about being cold – we have a full day and approximately 170 miles ahead of us. In case of breakdown or bits falling off the AJS, I keep off the motorways and follow the old departmental roads south. Plus, Normandy’s gentle green fields and half-timbered farmhouses feel wonderfully suited to the gait of the AJS. We keep to 45-50mph and I often find myself easing off the throttle to reduce mechanical stress and protect the bike. Unhurried, its engine note sits somewhere between a slow heartbeat and a promise as it rumbles through the hedge-lined roads.

Central France opens into wide fields, poplar lines and farmhouses older than most countries. In Beaugency, salvation arrives in the form of my mate Mark, who has ridden his BMW R1150GS through torrential rain to meet and accompany me back to Valbonne. Our joy that the AJS is still running is matched only by the relief that we aren’t drinking Chibuku and instead have plenty of beer and wine at our disposal.

My confidence is immediately higher the following morning as we drift through the Loire Valley, past Renaissance châteaux and sunlit vineyards, knowing I have a friend in tow. We’re sticking to 45-50mph progress again to avoid vibration-related part losses. It’s a leisurely pace, perfect for enjoying the stunning scenery. Our overnight stop is the Hotel des Docks in Digoin, a canal town shaped by 19th-century barge trade.

Rolling south-east on day four, the vineyards give way to Alpine foothills. Rain comes and goes, but the AJS handles it all without missing a beat... until it runs out of fuel as we coast into our Grenoble hotel car park. I call Cochon, who asks the obvious question: “Did you open the left reserve fuel tap?” Turns out I haven’t – crisis resolved with a flick of the wrist.

Alpine test

The plan for day five is to complete the 185 miles from Grenoble to Valbonne via Castellane. But a petrol station stop reveals oil bubbling merrily from the base gasket – all four barrel studs have worked finger-loose. Thankfully bikes like the AJS are simple to work on at the side of the road. A quick tighten and we’re off.

Mark summarises the morning’s ride: “Positives are no rain and the stunning scenery. And my bike’s sixth gear isn’t in danger of wearing out. Negatives? Being overtaken by cars, trucks, and a camper van...”

Climbing into the French Alps, the AJS thumps steadily through spectacular switchbacks. Snow-dusted peaks frame the route, while turquoise rivers carve deep gorges below. In Castellane we enjoy a leisurely pit stop lunch with Andrew, a friend who presents me with a panache-filled ‘AJS OIL ONLY’ trophy and joins us in his Bentley for the final 45 miles of the road trip into Valbonne.

The home stretch

Rejuvenated, I finally open the throttle properly for this final leg. Sensing the finish line, the AJS clocks an enthusiastic 70mph. Confidence is so high that I try to impress two female riders, but the AJS’s silencer grounds out and nearly sends me into the scenery.

Undeterred, the AJS and I roll triumphantly into Valbonne with fuel to spare. I’m greeted at our local pub with pints of beer and a welcome party, where I work out I’ve spent less on fuel than on wine through France – roughly 750 miles had cost just £76 in petrol.

This isn’t just a travelogue. It’s proof that classic motorcycles aren’t museum pieces but time machines still capable of real adventure. It may have been christened The Turd, it may have needed the cylinder barrel tightening, and it was overtaken by camper vans, but the AJS completed the length of France with style, soul and unmistakable British thump. It earned my respect and is now one of my favourite bikes. I regularly use it, including for semi-enduro on dirt roads – yes, really – which takes me back to those long-ago days in Malawi.

It has also influenced my job as a yacht designer – I now tell my clients I understand how they feel about buying their yachts and refitting them. It is not about cost; the passion and the process along with the final (and in my case sentimental) result are what it’s all about. The AJS cost a lot more than I was expecting (see boxout), and a French valuer says I would only get €1800 (£1560) if I was to sell it. But that’s OK, because it’s going nowhere.

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INTERVIEW
Honda are famous for V4s but their VFR750R RC30 is the most famous of all. Professor of mechanical engineering Jamie Turner explores what makes it so exceptional

Words JAMIE TURNER Photography BAUER, JOHN NOBLE, HONDA

For me, Honda will always be the V4 company. I guess I’m not alone in thinking this. They took a major bet on the layout to claim it at a time when Yamaha were threatening to usurp their position as Number One. In their own words, Honda ‘decided to develop a V4 series that would surpass existing inline four-cylinder engines in every respect’ and ‘become No.1 with its original technology’. They put it in all sorts of bikes, but the ones that really stick in the collective memory are the V4 sports bikes and sports-tourers.

The 90° V4 was really their thing, released to an eager sportsbike-buying public with the VF750F. At least, that’s where most people pick up the story, because that was – and very much not to script – an unmitigated public relations disaster due to its well-documented reliability issues across its entire valve drive system. We’ll come back to this. But first we should consider why Honda was keen on the layout in the first place.

Honda considers itself a four-stroke engine company. As a matter of principle, it pulled out of Grand Prix racing in 1967 because of rules which it saw giving an unfair advantage to two-strokes. However, as the reputation garnered in both GPs and at the Isle of Man started to wane, they realised they needed to be in the Blue Riband class again. And in 1977 they announced an intention to return using four-stroke engines with the ‘New Racing’ NR500 – the ‘oval-piston’ V4.

Honda chose the V4 because they were essentially creating a V8 with pairs of bores siamesed together to form four racetrack-shaped cylinders, each with eight valves. (As an aside, cylinders can – mathematically speaking – be any shape you like; it’s just that understandably we always imagine them to be round.) This was necessary because, during Honda’s hiatus, a limit on cylinder number had been enacted for GP racing, with a maximum of four in the 500 class. The resulting Spam-tin-shaped cylinders had their major axes parallel to the crank so the valves could be driven by two camshafts, valve area being the raison d’etre for the whole crazy confection, maximising this being key to competing with the dominant two-strokes. We’ll leave the long, painful NR500 story except to say that, because the concept was eventually somewhat successful in the NR750 endurance racer, Honda probably felt its sheer hard work wrangling it into being gave it the right to view the V4 configuration as its own.

Making it right
Having decided they had a moral right to V4 territory, it was then another rocky road for Honda to get there for its road bikes. In an uncharacteristic dropping of the ball, they had fallen foul of thinking that manufacturing excellence alone would let them shorten development time of the engines. These were launched in the V750 Sabre in 1982 – the world’s first mass-produced liquidcooled V4 – before the VF750F in 1983, and then VF1000F in 1984. Due to truly awful issues with all aspects of their chain-driven valve gear, these shiny new offerings did nothing to offset the reputational damage in having to drop four-strokes in GP racing (for the admittedly excellent NS500 stroker).

The travails were split between ‘chocolate cams’ and catastrophically wearing cam chain tensioners. These had different remedies, but the cam chain solution is what concerns us here. I imagine Honda was so fed up with setbacks and brickbats that it decided on the nuclear option: it went all in on gears for the cam drive, as used on the RS1000RW endurance racer. First to get them was the limited-edition VF1000R homologation special (1984 in Europe), followed by the VFR750F in 1986. And then what we’re really interested in: the VFR750R RC30.

One might presume, based on the model names, that engine-wise the RC30 was a mere evolution of the VFR750F (the RC24). I guess it depends on what you call ‘evolution’. Its core architecture was identical, with the same 90° V4 layout, bore, stroke, and a cam drive gear system fitted centrally between the cylinders. From there on, however, it gets gratifyingly geeky.

The heads, crankshaft, and even the gear drive were all different. The heads were revised to enable higher power output. This is easily understood, as was the theory behind the titanium con rods. But the RC30’s crank layout was different, too. Honda have historically used two different crank layouts in their V4s, nearly all using a so-called ‘360-degree’ arrangement in which the two crank pins (each of which carries two side-by-side rods) aligned with each other, so the pistons in each bank rise and fall together. The odd bikes out include the VFR750F and the first two versions of VFR400 (NC21 and NC24): these had 180° cranks with pins positioned like bicycle pedals. This was done for better rideability on the road but seems odd when everything else had the 360° layout – especially since both types give the same fundamental balance characteristics.

HRC had a dry run for the RC30 with the VFR750RK, a tuned version of the 750F (codename ‘6X’; see Startline, page 4), which used a 360° crank. One can immediately see why one would want a 360° crank from an engine-tuning viewpoint. With this pin phasing the cylinders fire 360° apart in each bank, meaning they can be tuned identically; primary pipe length is the most important parameter for exhaust tuning in a four-stroke, interacting with the secondary system mainly in terms of wave reflection when it meets the first collector. If the firing intervals are equal, the lengths can be equal too, with no big changes in wave effect between the two cylinders as engine speed rises. If the intervals or the lengths change, harmonics change through the rev range too, which might be beneficial in a road engine – and could have been Honda’s thinking for the 180° applications, although we may never know the full technical reason.

The RC30 also had a different cam gear drive configuration to the other V4s – but first let’s look at how Honda productionised the system.

‘We can get behind the ‘reassuringly expensive’ vibe’

Engineering deliciousness
All road-going gear-drive V4s used a cassette arrangement to slot the drive system into and through the cylinders from the top of the cylinder head, where it was bolted down. As a piece of high-volume production engineering, this approach is lovely. The intermediate idler gears are all held in the steel cassette, keeping their centre distances broadly constant.

A major problem with gear drives – from a refinement point of view, anyway – is that holding the distance between centres is crucial. If they move apart, backlash increases, giving rattling as the gears oscillate back and forth as the clearance opens up. Unfortunately, aluminium (used for the block and heads) has a high coefficient of thermal expansion, whereas steel’s coefficient is much lower. As a result, making the gear carriers from steel and constraining the system at the head meant only one clearance increased significantly as the engine warmed – that between the crank gear and the first idler. Honda solved this problem by adopting a scissor – or ‘split’ – anti-backlash gear for the first idler, where a spring forces two gear sections apart. Consequently, when the idler is pushed into contact with the crank gear during assembly, backlash is effectively eliminated.

In the cylinder heads, they also used sprung split gears on each camshaft, reducing any NVH (noise, vibration, harshness) impact from thermal expansion there. All this made for an absolute sledgehammer to crack the timing drive nut, gear drive being the ne plus ultra of such systems. But boy, are gears costly. Still, when you are deep in the existential mire, I guess even accountants look the other way.

Honda had previous with interesting gear drives, of course. The combined centre power take-off and cam drive of the 249cc, six-cylinder RC166 racer set a template, being adopted for a couple of reasons: to keep the engine shorter; and to give reliability.

But I mentioned that the RC30 differed from the other gear-driven VFRs in the detail of its cam drive. This is because while all the others (as far as I can see) used two intermediate gears in its cassettes, the RC30 used three. For reasons known only to the HRC project team, the central gear in the cassette was a ‘compound’ idler, not found in all those other engines. This allows a change in diameter for the gears further down the train relative to the original take-off gear, allowing the 2:1 reduction you need in a four-stroke to be achieved with smaller gears at the head end, which possibly gave packaging advantages. There is a price to pay, because it introduces two more gears into the engine (each being parts of the compound idler). Still, with a bike as costly and focused as the RC30, I think we can get behind the HRC ‘reassuringly expensive’ vibe…

All this gives rise to one piece of lovely nerdiness. With five gears in the train, the RC30 appears to be the only Honda gear-driven-cam V4 engine to have its cams rotating in the same direction as its crankshaft. In the others, because there are an even number of gears, the cams rotate backwards.

So, having fallen headlong into that particular geardriven rabbit hole, what was the effect of all this?
I don’t need to tell you how successful the RC30 was, at both the important stuff – racing – and the really important stuff: being a poster child for the brand. But it did have all sorts of competition in both those areas, so let’s pick a couple of fondly remembered rivals and see how it stacks up under the harsh glare of engineering science.

Outperforming rivals
I’m choosing the Ducati 851 and Suzuki GSX-R750J Slingshot. Both were contemporaries and both were successful in the same racing classes. The 851 was The Bike That Saved Ducati (before the Monster saved it again), although is perhaps somewhat overlooked because of the 916. The Slingshot was much more of an everyman hero than either the aristocratic Ducati or technocratic Honda.

After some rummaging around in the archives by editor Mike, we have the figures in the table over the page. You may say “hold on, the power claims were higher”, and indeed they were – but I’m listing values as measured by Performance Bikes magazine at the time, for reasons I will discuss later.

Let me explain some terms. BMEP is Brake Mean Effective Pressure and what engineers use to properly compare different engines. It is the pressure which, if applied to the piston through a single stroke, produces the equivalent work of the entire cycle; in reality, it’s a fancy way of discussing specific torque. Essentially higher BMEP is better, and the RC30 has the highest values at both maximum torque and maximum power.

MPS is Mean Piston Speed, or the average speed of the piston at given revs. It’s a function of stroke length, so no surprise that the Ducati’s is highest and the shortstroke Slingshot’s the lowest. But all the values are reasonable; just as well, as subjectively it’s how we compare the mechanical stress in reciprocating parts.

I mentioned that I’m using measured power from a dyno test. Since the torque values are manufacturer quotes, you could accuse me of not comparing apples with apples. Fair enough, but there is good reason. If I use claimed power values, I’m afraid there is a lot of variation and sometimes one ends up in an impossible situation: higher BMEP at maximum power than at maximum torque. Remember, BMEP is effectively specific torque, so it would mean engines with more torque at maximum power than at maximum torque. Is this the hand of PR or Sales departments? They must all have been at it in those heady sports bike days…

Let’s also ruminate on the RC30’s 360° crank versus the 180° in the F. The high outputs and tuning potential of the RC30 are all likely a result of its even-firing banks. While the F generally had a higher peak torque and a lower peak power, and was always flexible, I don’t see any reason to question the RC30 here – it has a really wide rev range between its maxima, and good BMEPs at them: it absolutely should be fabulously flexible.

Objectively, the RC30 was ‘best’ among its peers. No wonder Ducati exploited WSB rules almost immediately, enlarging race engines to 888cc and beyond. However, perhaps the most important thing is that – apart from the racing, paint job and posters – the RC30 (and its NC30 and 750F siblings) completely restored our faith in Honda’s engineering prowess. Yes, the cam gears are over the top – but every other component is lovely, too. It was indeed a (gear-driven) V4 victory.

Just what is it about V4s?

There is undoubtedly something special about V4s. To start, they really suit a bike. Engine width is about the same as the gearbox which, if mounted transversely, keeps the bike slim (and slim at your knees). Yes, it gets longer, but is manageable with the common Vee angles, and there’s choice in that.

Honda had a thing for 90° angles in fourstrokes, as Ducati do currently. But Ducati’s V4s use 90° mainly due to V-twin heritage, and they do some things very differently (quite apart from desmo valves in the high-power ones). 90° Vees have perfect primary balance, and since a V4 is essentially two V-twins, this allows the choice of any crankshaft pin angle you like without upsetting refinement: it’s what let Honda use either 180° or 360° cranks. Contrarily, Ducati stagger their pins by 70°, which results in slightly different secondary imbalance, but it’s not really an issue as this is lower in a V4 than an inline four anyway. (They’ve also reversed crank rotation using an idler to reduce gyroscopic inertia, but that’s not specific to V4s.)

You can, of course, change the bank angle, too. A primary imbalance arises and you need a balance shaft, but the narrower Vee angle helps shorten the engine. Again, a packaging/balance trade-off.

Any relatively wide Vee engine also has good under-piston pumping. Reciprocation of the pistons means gases need to be moved around the crankcase; in a shared-pin engine it essentially goes to and fro across the bay. No Suzukistyle link passages needed to join adjacent cylinders, then.

V4s also look expensive: doubling of the heads, cams and drives is readily apparent. Then there’s how they sound and feel. A four-stroke V4 has uneven firing – even if the 360° crank of the RC30 did alleviate some of the tuning impact. Our simple brains like the sound produced, and the aural signature changes with the architectural choices, giving character. Plus, the slight lumpiness reminds the rider of a degree of individuality without having the same got-to-ride-around-it nature of a V-twin.

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