Some people dream of owning a legendary GP bike. Alex Arletti and his crew built four from scratch – proving that with enough skill, obsession and a touch of madness, anything is possible
Alex Arletti likes a challenge. That much is obvious from his project – the most ambitious, complex and downright mind-blowing we’ve ever come across. Over the last four-plus years, Alex and friends Carlo Mattarozzi, Claude Hauser and Franck Virmaux have built four exact replicas – one each – of Yamaha’s final two-stroke 500cc Grand Prix bike, the 2002 YZR500 OWL9.
And when they say built, they mean built, having engineered, manufactured and constructed them from the ground up in every conceivable detail. Including the 123kW (165hp) V4 two-stroke engines.
Despite coming from manufacturing and engineering careers, none of them had a background within the motorcycle industry. And to add a further layer of difficulty to an already complicated project, the team was spread across two countries; Alex and Carlo in Italy, Claude and Franck in France. So, with both geography and a language barrier to contend with, bringing everything and everyone together has been a project in itself…
“We’re just enthusiasts who had a crazy idea,” says Alex rather understatedly. “I came up with the initial plan; I’m an old-timer Yamaha enthusiast. Carlo had experience of building Morbidelli race replicas in his spare time using Yamaha 350 and 500 engines. He lives nearby and I met him at an exhibition in Italy where he was showing past builds. I asked him to get involved in my project, to build a ‘real’ Yamaha 500 replica, but he wasn’t so confident at first. I think I must have worn him down because in the end he accepted the challenge!”
Two became three when Carlo brought Claude on board – Claude and Carlo met through a shared interest in building specials – and Claude had long been trying to persuade Carlo to join him in a project using a Swissauto V4 sidecar engine. Franck, a mate of Claude, was the final piece of the puzzle.
Four to the floor
Replica 500 GP bikes are nothing new. Indeed, Yamaha, Suzuki and Honda produced their own road-going nods to the class during the mid-80s with the RD500LC (RZV500), RG500 and NS400R. A steady stream of homegrown doppelgangers have emerged ever since from sheds, garages and small businesses across the world, almost always using engines from the aforementioned trio.
But Alex’s idea to build a YZR500 replica differs from 99 per cent – if not 100 per cent – of all others. He didn’t want to use a donor engine, road or race. Only an exact copy of Yamaha’s own race V4 unit would do. And that was no small task; factory race parts aren’t something you buy over the counter, and even if you can find spares, you’ll rarely find enough to build a complete engine.
Instead, our four intrepid enthusiasts had to cast and machine all four sets of crankcases, build their own crankshafts, and even create replica Mikuni carbs from scratch.
Carlo – a technical chief for a company manufacturing small items for the fashion industry, such as belt buckles and accessories for shoes and bags, now retired – took charge of engine construction. Part of the reason Alex decided to build a YZR replica, rather than a Honda NSR, Suzuki RGV or Cagiva C594, was not only down to his affection for Yamahas, but also necessity.
“There’s more information and data readily available on the Yamaha than the Suzuki,” he explains, “and the YZR’s twin-crank layout is easier to replicate than the Honda’s single-crank arrangement.”
In preparation for creating the engines, Carlo was able to garner useful information from several sources, as Alex explains: “We were given access to a proper 500 Yamaha at a museum near us in Italy, so we were able to take measurements and see how it all fitted together. We also obtained some broken engine parts that we were then able to reverse engineer, as well as some drawings and information from Japan.”
Carlo cast the aluminium crankcases, barrels and heads from scratch, before machining the mating faces to a GP standard finish. “We were fortunate that Carlo had previous experience of casting from his Morbidelli projects,” says Alex. Engine spec and architecture is as close to the Yamaha factory blueprint as possible, but a few compromises had to be made.
The crankshafts, for example, run slightly different bearings to pukka YZRs simply because the race-spec split bearings were unobtainable. Conrods are YZR spec, made by Italian crank and rod specialists Primatist, and pistons were produced by Wossner to the team’s own spec. “They’re similar to RGV250 pistons, just slightly shorter and without the lubrication holes,” says Alex. “We’ve even got our own part number for them. We also run a 50mm x 56mm bore and stroke, which matches the 90s Yamaha and parts we had access to, rather than the OWL9’s 54mm x 54mm.”
Skin in the game
Despite the obvious difficulties created by a four-man, two-country build, the advantages of their set-up far outweighed any logistical or communication issues, as Alex explains: “Had I attempted this alone, I almost certainly wouldn’t have achieved the level of manufacturing or construction a project like this demands. By coming together we were able to combine our specific experience and competencies, and work on areas of the bike that best suited our own skills.”
The other advantage of a multi-person build – all with skin in the game – is motivation. All projects throw up moments of doubt and/or seemingly impossible problems. A build of this complexity could easily overwhelm an individual on their own – even a gifted engineer – but, as Alex affirms, they found strength in numbers.
“At the start, I don’t think any of us even dared think about the final result. We simply figured out each part one by one. Of course there were times when our motivation dipped – it’s impossible for it not to over four years – but we had each other to pick us back up again.”
Claude’s skill is detail. Having worked for Rolex in Switzerland, his intricate engineering nous proved a perfect match for manufacturing four sets of Mikuni replica carbs. Indeed, there was no other way. No one makes a bank of carbs compact enough to fit between the vee of the cylinders so, as with the crankcases, the team cast their own carb bodies before handing them over to Claude to create all the internal parts – jets, floats, slides, the lot. Alex then designed a pressurised airbox to sit in front of the engines. Another friend of his, skilled in carbon fibre construction, turned Alex’s idea into a reality – times four, of course.
Franck had previous experience working on CAD design and transmissions at Renault, so the bikes’ gearboxes fell to him. Using data and specs garnered from Yamaha, he was able to work out what ratios were required and how the gear clusters, selectors and shafts would fit inside the cases, before passing his drawings and technical info to specialist gearbox manufacturers Micozzi in Italy, who then manufactured the components. Carlo created the dry clutches around Ducati baskets that matched the teeth on the primary drives, which he also made.
The chassis fell to Alex. Although an accomplished automotive project manager, with Ferrari as one of his recent clients, this project was the first time Alex had built a frame or worked with sheet metal tools. Working out the correct dimensions for the frame and chassis proved relatively easy, using pictures of Yamaha’s own OWL9s as reference. Knowing exactly how Yamaha braced the units internally proved far trickier.
He’s clearly a fast learner, because the finished aluminium beam frames and complex braced swingarms look like they were expertly constructed in Yamaha’s own race shop. “I tried to do my best,” he says modestly of the beautifully milled, crafted and welded chassis, “and made a design using pictures as a reference and my background experience. The hardest part was getting the correct shape and dimensions for the beam sections of the frame – it was quite a learning process.”
Yamaha has long outsourced suspension, wheels and brakes on its race bikes to experts so, just like the works YZRs, these replicas run Swedish Öhlins forks and shocks, plus Italian Marchesini wheels (Franck opted for cast aluminium; the others magnesium) and Brembo brakes. To help keep costs down – a key component of the whole project and the reason behind so much of the work being done inhouse – the suspension and brake components were bought secondhand, then refurbished.
Firing ’em up
Manufacturing and constructing a motorcycle is one thing. Getting it to run properly is quite another, and in the case of these four YZRs, that matters because they’re not trinkets or ornaments – they’ve been built to be ridden.
“Claude was the first to try his bike,” says Alex. “None of us have any race experience, so it’s hard to judge the potential of bikes like these, but he was very impressed with the cornering performance of the bike. For me, I’m more impressed with the engine performance. It’s very strong, and we’ve already seen 165hp on the dyno. There is certainly room for development, but the initial aim was to have a useable, reliable motor. The result certainly meets all our expectations.”
Each bike is personal, too, sporting the colours of a specific team and rider from 2002. Alex’s YZR is finished in Red Bull livery, as ridden by German Alex Hoffman – then rider for Team WCM. “That way I can run my own name on the screen,” says Alex. “And his race number ‘66’ is the year I was born.”
Carlo was a Max Biaggi fan, so his was always going to be in Marlboro red and white. Franck’s runs the same Marlboro hue but features the number ‘7’ of Carlos Checa. Claude, being French, opted for the blue Gauloises colours of his fellow countryman Olivier Jacques.
As if to prove just how remarkable these YZR replicas are, even Yamaha showed its appreciation for the project, inviting Alex and Carlo with their 500s to Jerez in July last year to take part in its Yamaha Heritage Racing Club event alongside a plethora of former and current MotoGP, WorldSBK and endurance racing stars.
“We got to share the track with Valentino Rossi, Luca Cadalora, Jonathan Rea and other star riders who were not only enthusiastic about our bikes, but also gave very positive feedback. They all remarked positively about the power and handling of our bikes, despite the fact many of them had not ridden two-strokes before and remarked about the lack of low rpm power! There’s footage on the internet of current Pata Yamaha WorldSBK rider Andrea Locatelli getting his elbow down on Carlo’s bike. And Luis Cardoso, who rode a factory OWL9 back in 2002, was also really positive about the bikes.”
A crazy idea that worked
It’s been quite the journey for Alex, Carlo, Claude and Franck, four enthusiasts who set out with a crazy idea and the determination to see it through despite the obvious complications and restrictions of their situation, as well as the sheer complexity of the project. Reflecting on what the quartet has achieved, Alex doubts it’s something an individual could do on their own, but if they did, it’d take a lot longer and require a fair bit of outsourcing.
“For a project like this,” he muses, “you need to be determined and a little bit crazy. Oh, and join forces with a bunch of like-minded crazies.”
Told you he likes a challenge…
YAMAHA OWL9 – THE YZR500’S LAST HURRAH
YAMAHA’S YZR500 terrorised the world’s racetracks for 30 years, first appearing in 1973 as the across-the-frame, piston-ported OW20. Over the following three decades, the YZR evolved briefly into a square-four and then a V4, winning 10 world championships – its first with Giacomo Agostini in 1975 and last with Wayne Rainey in 1992. The YZR also brought a host of technical firsts to GP racing’s premier class, from powervalves, aluminium beam frames and ‘banana’ swingarms, to electronic telemetry and carbon fibre brakes.
The 2002 OWL9 was the 28th and last iteration of Yamaha’s 500cc two-stroke racer. Subtle tweaks were made from the previous OWL6. The engine was brought forward slightly and CoG altered to compensate, while the swingarm was made from slightly thinner, lighter aluminium.
In 2002 the OWL9 competed against both two and four-strokes, the latter being the-then new 990cc MotoGP missiles that represented a new chapter for GP racing’s top class. Although down on power against the 200bhp-plus four-strokes that year, the YZR still managed to take pole position at the German GP in the hands of Frenchman and former 250cc champ Olivier Jacques. Japanese star Norick Abe managed sixth overall in the series that year aboard his Antena 3 OWL9.
SPECIFICATIONS
ENGINE
Type Liquid-cooled, 70° V4 two-stroke with YPVS
Capacity 499cc
Bore x stroke 56mm x 50mm
Carburation 4 x Mikuni (clone) TMW 35mm
Ignition programmable Zeeltronic CDI
TRANSMISSION
Primary/final drive Gear/chain
Clutch Dry, multiplate
Gearbox 6-speed
CHASSIS
Frame Aluminium beam
Front suspension 42mm Öhlins FGR fork, adjustable preload, compression and rebound damping
Rear suspension Öhlins TTX shock, adjustable preload, compression and rebound damping
Front brake 2 x 320mm Brembo discs (Claude’s bike runs ex-factory carbon YZR discs), 4-piston Brembo monobloc calipers
Rear brake 200mm disc, 2-piston Brembo caliper
Wheels 5-spoke cast magnesium Marchesini (Franck’s bike, forged aluminium)
Tyres 120/70 17 (front), 190/60 17 (rear), Pirelli slicks
DIMENSIONS
Wheelbase 1400mm
Dry weight 145kg
Fuel capacity 26 litres
PERFORMANCE
Power (measured) 123kW (164hp) (Claude’s bike, on dyno)
Top speed 313km/h (est)
