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The Rare Vincati

Vincati, Ducati and shadetree mechanic Don Henderson unite to customize an original superbike.

Vincati-front
by Phil Aynsley

The 1970’s bred a worldwide generation of “shadetree machanics.” These were people with the self-taught skills of certified mechanics and engineers who undertook hobby projects in their basic backyard workshops.

Some of their often crazy ideas worked: fitting a Volkswagen engine into a motorcycle frame; slotting a 427 Cobra Jet V8 engine into a 1955 Ford Ranch Wagon to make the ultimate “street sleeper” — and let’s not even talk about the craziness of Unlimited class hydroplane racers using aircraft engines.

Vincati-engine

Many of these shade tree mechanics created their own little subculture. In Australia one tiny niche of the customizing scene saw at least five Vincatis built. This is the second of them. An unlikely marriage of a bevel-drive Ducati V-twin’s frame and a 1,000cc Vincent engine, the professionalism of the build is amazing. The execution is so precise it could almost have come from a major motorcycle factory, not an enthusiast’s workshop.

Looking back more than 40 years it seems sacrilege to mess with a Ducati and a Vincent in this way. Both now command among the highest prices at classic auctions if they are in original condition. But times were very different back in the 1970s.

Vincent’s V-twin Series C Rapide was considered the world’s first “superbike” when it arrived on showroom floors in 1948. Certainly Vincent thought so, advertising its 110mph top speed as being “the world’s fastest production motorcycle.”

Vincent-engine

By the 1970s Vincents had long lost their aura and could be picked up for amazingly cheap prices. In Australia, the hugely popular sport of speedway saw many highly-tuned, methanol-burning Vincent engines powering championship-winning sidecars. This decade also saw Australia become one of Ducati’s biggest export markets, with the 750 GT twin its most popular model Down Under.

As the decade wore on and the Ducatis started to wear out they became relatively cheap to buy secondhand. Sadly, this sometimes meant they became a blank canvas for fans of the “chopper” era. And that is where the story of this Vincati begins.

Frame first

Vincati-right

Don Henderson was on the verge of retiring from his country Victorian motorcycle shop in 1977 when he traded a Honda Four for a chopped 750 GT with a blown engine. Extended forks and a 16-inch car wheel in the rear wasn’t exactly what he wanted, but the chassis was.

A few years before, his friend Max Johnson had built the world’s first Vincati, inspiring Don to do something similar. He had already bought a 1948 Rapide engine, which had survived being used in a speedway sidecar outfit. Don returned it to largely stock form, then borrowed some engine plates from Max to begin the trickiest part of the project.

Vincent engines had been part of the Norvin subculture in the 1960s, squeezed into a Norton featherbed frame. To get the big engine to fit most builders simply sawed off part of the gearbox housing, rendering it unusable in any future restoration project.

Don took a different route, making up several sets of prototype engine plates until he was satisfied the V-twin engine sat low enough in the frame but without any standard parts being modified.

handlebars

The intention was always to keep the engine in original condition so it could be returned to a standard Vincent rolling chassis in the future. In fact this is exactly what happened eventually to Max’s first Vincati, which was broken up and the engine put back into a Vincent.

Once he was happy with his design Don carefully cut off the Ducati frame’s front down tubes, ground off the remaining engine mounts and welded in his engine plates. Here too everything was reversible. If it was ever decided to return the Ducati to standard condition all that was required was to weld back in the down tubes and original engine mounts.

Don also ran sturdy mounts from the Rapide’s cylinder heads to the top frame rails, hidden under the gas tank, and the steering head area was reinforced. With the engine fitted, work continued on the chassis. The Ducati engine is a wet-sump design so Don had to make up his own oil tank, which he did, incorporating a tool tray.

Road test

Once finished Don and his wife, Gladys, went touring on the Vincati, taking it from their home state of Victoria 1,200 miles north to Queensland.

Despite being loaded with luggage and two riders, the bike happily ran at 80mph with the engine ticking over at a lazy 3,500rpm. Proof of the value of keeping a Vincent engine largely standard was the fact Don could fit high gearing to take the stress off the old engine.

left side

Further important additions to ensure reliability included fitting 30mm Mk I Amal carburetors instead of the fiddly standard Type 6 carbs that have separate float bowls. A Suzuki GS850 clutch was also adapted and fitted to replace the more complicated and sometimes cranky Vincent setup.

The Magnet ignition remained, but with a rare set of original Vincent-Lucas platinum points. The generator was converted to 12 volts and a solid-state rectifier was fitted.

One interesting point to make is that the Vincent engine might look much larger than the Ducati unit, but it only weighs about 10 pounds more. With it mounted at optimum height in the frame there was little difference in handling and braking from the 750 GT.

Several more Vincatis were built after Don’s, with at least three of them being converted back to Vincents and Ducatis when prices started to soar in the 1990s.

Vincati-rear

Don was approached in 2000 by two Americans hoping to build their own Vincati. He readily provided Sidney Biberman and his son Matthew with engine plates and fitting instructions.

The result was “Big Sid’s Vincati”, which became an internet sensation.

A new acquisition

Don’s Vincati now resides in a private collection in Tasmania, where its new owner, Paul Dickson, takes much pleasure in owning this unique machine.

He says Don became a mentor for him regarding everything to do with historic motorcycles, and they became great friends more than 25 years ago until Don’s passing in 2005. A well-timed phone call to Gladys eventually resulted in the new acquisition in 2010.

“I have spent time upgrading the bike both mechanically and electrically,” says Paul, who rides it regularly on the winding, two-lane backroads that make up the motorcycling nirvana Tasmania is so well known for.

Vincati-right

Paul fitted an Alton alternator and BTH electronic magneto to ensure reliability but removed an electric starter that had been fitted as he prefers the clean lines of the Vincent engine.

Other indications of Paul’s commitment to serious road riding are the fitting of twin-disc front brakes with Brembo calipers and sticky Avon tires.

A crisis point arrived when it was revealed that the crankcases had hairline cracks, most likely caused by the engine’s speedway racing past.

Most of the parts for a complete rebuild were provided by Melbourne Vincent identity Neil Videan. Another well-known Australian Vincent technician, the late Laurie Binns, overhauled the cylinder heads and barrels while yet another Vincent stalwart, Ken Phelps, provided assistance with the crankshaft.

Vincati-wheel

One particular feature Paul is proud of is the one-piece, two-into-one stainless steel exhaust pipe, manufactured by Tasmanian custom exhaust firm VEREX.  An original Vincent exhaust has two headers and one muffler but this setup pays homage both to Vincent and Ducati, with the long megaphone looking more like a Ducati’s Conti.

Paul says riding the Vincati is similar to a standard Ducati 750 GT except the engine sound is quite different (50-degree instead of a 90-degree V-angle) and there is a little more low-down torque from the bigger 1,000cc engine.

Often specials can look spectacular but feel like a compromise to ride. This certainly doesn’t appear to be the case with the Vincati. “It doesn’t feel out of the ordinary at all, everything seems to fit just right,” Paul says.

test ride

Visually what made Ducati’s 750 GT so popular was its perfect blend of gas tank, 90-degree L-twin engine, seat, side panels and exhaust. Everything was in proportion in an understated but distinctive style.

Don managed to duplicate the effect with his Vincati, and also make it perform at least as well as the two motorcycles it was based on. To sum all this up, it was a triumph for the shadetree mechanics of this world.

Published on Oct 5, 2021

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