The Irving Vincent 1300

By Alan Cathcart

A long look in the rearview mirror at all our motorcycling yesterdays has become increasingly commonplace these days. Triumph’s Bonneville and Scrambler, Royal Enfield’s Bullet and Ducati’s Sport Classics prove the point well, as does this homage to Phillip Irving’s immortal V-twin, the latest in a line of revivals.

Not all revivals have been met with excitement though. Few retro bikes aroused such instant disapproval as the Honda-engined Vincent Black Lightning that Bernard Li hoped to have on the market by 2004. Li somehow succeeded in registering the trademark of Britain’s most iconic brand in the U.S., and while Li’s Vincent appears dead — mercifully, some would say — its existence may help explain the contrasting acclaim being accorded to a more faithful revival. Australians Ken Horner, 53, and brother Barry, 52, have taken aim at a contemporary revival of the same marque, under the Irving Vincent name.

From racing classics to building one
The project’s origins lie in Ken’s career as a successful sidecar racer in the 1970s with a self-built 1,300cc Vincent outfit. He later retired from racing, and in 1977 started his own engineering company, Melbourne, Australia-based K.H. Equipment Pty., leaving brother Barry to fly the family flag on three wheels. Barry did so by finishing a close second in the Australian GP at Bathurst one year and by leading into the last lap there in another race, only for his chain to break on the run to the flag: Disappointments don’t come bitterer than that.

Meanwhile, K.H. Equipment Pty. worked its way to success manufacturing air starter motors for the mining and fuel
exploration (i.e., oil and natural gas) industries and now exports half its production to China and the U.S. Importantly to this project, the company also manufactures trick race components for one of Australia’s leading V8 Holden Supercar teams.

In fact, it was thanks to their race car connections that the brothers came into contact with legendary Aussie designer Phil Irving, the creator of the Vincent 50-degree V-twin and, later on, Australia’s title-winning Repco race engine, which took Jack Brabham and Denny Hulme to a pair of F1 World Championships in 1966-1967.

“I first met Phil around 1971 when I was racing the Vincent, and he was living here in Melbourne, working on the Formula 5000 Repco engine,” recalls Ken. “He had a small sideline dealing in Vincent parts, which were increasingly hard to get, and I ordered an oil pump from him and went to his house to collect it. After that, I had a direct phone line to him, same as anyone who had a Vincent and needed parts or advice. Then Barry started to deal with him on another front, and we got to know him more closely.”

Barry takes up the story. “I’d been to Europe in 1978, visited the Isle of Man TT, but then came back to finish off my apprenticeship as a machinist with John Brookfield, a top fabricator who’d worked with Irving on the F1 Repco-Brabham. I got to know Phil there, and when he designed a set of Formula 5000 heads for the V8 Leyland P76 motor, he asked me to machine them for him, which I felt was quite an honor.

“Anyway, we made several sets for him, which proved to be very good, and he started expressing an interest in what I was doing with the Yamaha TZ750 sidecar outfit I’d built and was racing.

“One day he asked, ‘Do you think you could make some Vincent heads?’ I was still getting my head around this when he said, ‘No, never mind — they’d never sell, anyway’ and changed the subject. But that stayed in the back of my mind, even after he passed away in 1992.”

After a six-year sabbatical from motorcycles in the 1990s, they built themselves a 46-foot sailing yacht. “We did a good job in fitting it out, joined the yacht club, bought the right hats, and tried to acquire a taste for Sauvignon Blanc — but the chemistry just wasn’t right,” Barry says. “So, we sold the boat and went back to our grass roots in building bikes — and that’s when I remembered what Phil Irving had said to me about the Vincent heads. We sat down one evening and thought it over and realized we should build a new Vincent motor — three in all was the original idea, just for classic racing. We were doing this for ourselves, not the public.” That’s how it started, anyway.

The Vincent revived
Around this time, in 1999, Australian restorer Terry Prince’s attempt to revive the Vincent marque had crashed in flames, leaving the Horners with access to Prince’s heads and barrels, for which they intended to create three pairs of crankcases to build a 1,300cc engine, the top limit for classic racing sidecars Down Under. But when the Irving Vincent solo made its debut at Phillip Island in January 2003, it became the first of a crop of Irving Vincents entirely manufactured by K.H. Equipment.

“We decided to make complete bikes ourselves, with the engines based on the original design but stretched in capacity and re-engineered to correct all the original shortcomings,” says Ken. “We didn’t want to call them Vincents because of having to pay royalties to the Holder family, who own the Vincent name, if we did. So we decided instead to call them Irving Vincents, to underline Phil’s contribution to the marque, for which he never got due recognition. We got approval for doing that from his widow, Edith, before registering the name.”

The first Irving Vincent sidecar appeared in Barry’s hands in January 2004 and duly won the New Zealand Historic title a year later, as well as the prized Ken McIntosh Trophy for excellence in motorcycle engineering. This was followed by the fuel-injected 1,600cc jumbo Irving Vincent solo in February 2005, and 13 months later by the fourth and latest in the crop, a 1,300cc classic racer with a plain-bearing engine built to compete in the Period 4 category of Down Under historic racing.

Sharing the wealth
Response to the project has been so overwhelming that Ken and Barry have decided to start a limited production of 10 bikes a year in either road or race guise for customers around the world. “We don’t want to make any headaches for ourselves by making promises we can’t keep,” says Barry. “We enjoy what we do, and plan to keep it that way. But a de-spec’d version of the race bike would be within our capabilities, and that’s what we’ll be working on next — though there are no promises as to when it’ll be ready. We’re not taking any orders!”

Engine no. IV-0004 of the six built to date powers the latest evolution of the Irving Vincent species, our feature bike, and is the only one so far to run on gas in preparation for the Irving Vincent street version café racer that’ll appear next (though for race purposes, it’s since been converted back to methanol). This is an under-square, long-stroke 1,295cc version of the brothers’ externally faithful recreation of the 50-degree V-twin, high-cam, overhead-valve Vincent dry-sump engine. It was created entirely in Australia by K.H. Equipment, with heavy duty crankcases with provision for fitting a Nippon Denso starter motor and alternator for the street bike. The plain-bearing crank and Carrillo rods are made in EN26 steel, with Nikasil-bore cylinders housing JE pistons running a hefty 14:1 compression.

While the heads fitted to the test bike are the original-spec design with stock 65-degree included valve angle, new big-port cylinder heads have been designed by Ken Horner for the 1,600cc engine that feature a much narrower 50-degree valve angle. “In terms of cam profiles and combustion chamber design, we just treat it as one-quarter of a V8 Supercar motor,” Ken says. “That way, we can plug into acquired knowledge of all the people we know who work on those engines.”

This meaty engine is installed in a modern chrome-moly replica of a period Vincent spine frame, with the three-liter oil tank incorporated in the backbone. A set of 38mm Ceriani forks — fitted with Kawasaki motocross dampers and Ohlins springs — set at an angle of 25 degrees controls steering. This delivers a 56.5-inch wheelbase with 3.9 inches of trail, resulting in a 52/48 percent distribution of the Irving Vincent’s 407 pound dry weight.

Rear suspension comes courtesy of a fully-adjustable Ohlins monoshock fitted to a traditional Vincent cantilever swingarm that’s a replica of the one fitted to a D-series Rapide, while for the time being (as Period 4-class eligibility issues are thrashed out) there are cast iron disc brakes all around, with twin 12.6-inch front rotors and an 11-inch rear, all gripped by twin-piston Grimeca calipers. Finally, 18-inch Akront alloy rims laced to a Honda hub up front and a Norton at the rear are shod with Avon racing tires.

On track
With the bike literally finished the night before our shakedown test on the bumpy, switchback track of Broadford, north of Melbourne, I was prepared to have to spend the first part of our sunny summer session dialing-in the freshly-minted bike. It didn’t need it.

The engine was actually Barry Horner’s well-proven spare engine from his sidecar outfit, but after watching the brothers fire it up using a remote starter, I took to the track and
discovered that the bike was ready to roll, straight from the womb. But not to rock, for the Horner-built motor is incredibly smooth for a 50-degree V-twin with such big pistons and no balance shaft. There’s no vibration at all even through the footrests, let alone the seat or bars, indicating that the brothers know a thing or two about getting the balance factor right. The lumpy 1,300rpm idle it settles to after firing up soon smooths out as you rev it off the mark. From 3,000rpm upward the engine makes serious power by classic racing standards, sending the Irving Vincent rocketing out of the final turn at Broadford to the staccato accompaniment of that lazy-sounding exhaust that belies the speed at which it’s traveling, before thundering down the straight like a jet-propelled cannonball.

Acceleration is so emphatic that you’re best getting the bike upright as soon as possible, and pulling the trigger to max out drive from the meaty engine.

You must be careful using the rear brake too hard with the massive inertia under engine braking of such a big twin. I got the rear wheel chattering a couple of times when too eager to hit a lower gear at the end of each of the Broadford straights. You must learn to ride such a mega-motorcycle in a very measured manner — do so, and it’ll pay off in lap times.

The only negatives were poor front brake performance and a very stiff throttle, perhaps a spin-off from the heavy springs needed to combat the suction effect of such a deep-breathing big-bore engine. But that aside, the Irving Vincent fully lived up to its promise on paper, with an impressive dyno sheet reading born out by the V-twin engine’s real-world performance.

The born-again Aussie Vincent feels relatively tall when you first straddle it, and there’s a good stretch across the 5.8 gallon fiberglass fuel tank to the high-set but wide-spread clipons bolted to the top of the Ceriani forks. The forks have been pushed up through the upper triple-clamp around 60mm, bringing the front of the bike down to sharpen the steering and improve front end weight bias for extra grip in the turns. It works, as the Vincent isn’t light steering, but is not as slow as I was expecting, either. The wide bars deliver good leverage for hustling the bike through Broadford’s tight bends, and while the spring on the rear Ohlins shock is pretty stiff to cope with all that torque under acceleration, it still felt reasonably compliant over Broadford’s bumps.

The cocktail of ingredients in the 38mm forks worked very well, with what was probably the best feedback from the front tire through a set of Cerianis that I’ve ever experienced. I spent the best part of a decade racing with the Italian suspension, so compliments to Ken and Barry for getting it right straight out of the box.

And well done, too, for reviving the Vincent name in a way that Phil Irving himself would have approved of. The Horner brothers have followed in Phil’s footsteps by producing a modern re-creation of his most iconic engine, which I’m perfectly certain he would have applauded for the excellence of its execution, as much for the logical development path for his period design which it surely represents.

This is a glance in the rearview mirror of history that was worth taking — but we now look forward to the Ohlins-equipped, disc-braked Irving Vincent 1300 street bike that’s coming up next, which will bring the Horner brothers’ homage to a giant of motorcycle engineering to a wider public.

I can’t wait, but in the meantime, I reckon the Honda fours that currently dominate Aussie Post-Classic racing better get ready for some serious competition, because in the right hands, the Irving Vincent 1300 just might be a potent threat to that Oriental supremacy. Just as Phil would have liked it to be. MC