During the Sunday Ride which will take place on May 6 and 7 on the Paul Ricard circuit, one of the countless attractions will be the start of a Yamaha 500 YZR V4 replica entirely built from A to Z by four perfectionist enthusiasts who have not was afraid to embark on this crazy adventure! Because it is indeed a crazy adventure…
Claude Hauser, a member of Spirit of Speed of which he is part of the committee, tells us how this Franco-Italian project was born and is today approaching completion.
Claude Hauser : “ Initially, I followed on Facebook Carlo Mattarozzi who had made among other things six Morbidelli replicas, 250 twin-cylinder, 350 twin-cylinder, 350 four-cylinder as well as a sort of Rotax engine with the cylinders a little more inclined. So I admired his work and while going to Dijon, to Moto Légende, I saw a magnificent replica of Morbidelli. Indeed, it was indeed one of his motorcycles and we started talking. I mentioned the fact that I wanted to remake cylinders for Rotax, a little improved but with the look of the time, and he invited me to come to Bologna. So I was lent an Aprilia 2007 cylinder that I tomographed to get the shape of the transfers. Then, I redesigned the cylinder then made the molds to make a series of cylinders with the collaboration of Carlo Mattarozzi who knows a whole network of subcontractors well, whether for sand, foundry and all these things. »
« Then I wanted to rebuild the Swissauto engine. For what ? Because basically I'm a bit Swiss-German (laughs) and I think it's a magnificent engine because it's even more compact than the Yamaha 500. There, he tells me about another friend who is in Modena, Alex Arletti, who had made chassis to put RDLC 500 engines and who now wanted to make a real motorcycle with a real racing engine. SO Carlo Mattarozzi suggested that I make a replica Yamaha engine instead of the Swissauto, and as initially I already intended to redo the Mikuni carburetor rails for these motorcycles, I said why not. This is how the story began. »
« So I did the same thing again, tomography, that is to say X-ray scanning to see the inside through the metal, half of a Mikuni carburetor. Meanwhile intervened Franck Virmaux who transformed all the scans into drawings to be able to machine, and this is sometimes very difficult when it comes to awkward shapes. He therefore redesigned the carburetor ramps and the lower engine case, since I was able to recover the molds for the upper engine case from ROC who had made a copy of the Yamaha engine. Besides, at the time, Yamaha had forbidden them to ride with it, because it was frankly a copy with all the internal Yamaha parts inside: Crankshaft, gearbox, etc. »
« Virmaux also redesigned the crankshafts and the gearbox, Carlo Mattarozzi built 95% of the engine, I made the carburettors and Arletti made the chassis. I also machined the steering columns and on the engine I made the selection barrels because I was the only one who could do four simultaneous axes to make the cylinders and the forks of the selection barrel: it's a piece which is still quite complex. We all did this alongside our jobs, except me who has been retired for a year now, and we started more than four years ago. »
Can you tell us a little more about yourself? Where does your passion come from and where does your ability to machine come from?
« Basically, I trained as a precision mechanic. I'm not going to misuse titles that I don't have and I'm not an engineer, but I worked at Hispano Oerlikon, a company that made armaments in Geneva, and at the same time I had a neighbor who did the Swiss motorcycle championship, and I worked as a mechanic for eight seasons for him. One thing led to another, I found myself buying an Egli with a Rotax engine that I still drive with, the one from Jacques Cornu. But after a few seasons, life meant that I moved away from the racing world, and at the professional level I worked for 3 years at the engineering school in Geneva then, then 10 years on my own in machining, I ended my career at Rolex for 23 years. »
Regarding the chassis, what did you do?
« It is an aluminum perimeter chassis built by Arletti, an exact copy of the ROC chassis because we were able to have the geometric plans easier by Martial Garcia. There is just the swingarm which comes from a Yamaha R6 and which we modified so that it resembles an original swingarm as much as possible. »
So you are building four motorcycles since there are four of you: Is this collaborative work an advantage?
« Being a foursome is pretty good, because on such a long project, we sometimes have slack times, and the fact that the others are moving forward pulls everyone forward. »
Let’s talk about it: How much does it cost?
« It's a huge job but we only billed ourselves for the materials, not the hours. I haven't done the calculations but at a glance I would say that each motorcycle costs us between €25 and €30. »
Honestly, I would have said more. For example, to make a cylinder, aren't those crazy prices?
« No, contrary to popular belief, it's not that expensive. Take the case of Rotax cylinders. At first, I wanted to make a dozen, depending on who was interested. In the end, I made 26 which I sold in all countries, England, United States, Canada. The big job is making the models. Initially, it was carpenter-modelers who made the foundry molds. They built the shapes with wood and made boxes around them to hold the sand. The model is positive, the sand is negative, then we put the cores, the water chamber, etc.
But once all that was done, between the sand and the foundry, it only cost €80 per cylinder. We pay for aluminum by the liter, between 12 and 20 euros per liter, and there are not large quantities. Contrary to what people believe, what is expensive is not the foundry, it is the wooden models. This is where the hard work is, and if you ask a specialist company it can cost you up to €25. »
« For carburetors, the models are in seven parts, and that's a lot of parts and tools. And since you machine in sweeping, there are a lot of hours of machining and that's why it's quite expensive if you have them done. This is also why we did everything ourselves, because we would never have been able to pay for all this work if we had had to do it. »
So we come to another interesting part: You have gradually equipped yourself with sophisticated machine tools at home…
« Absolutely ! At home I have a CNC lathe and a CNC milling machine. For the record, the milling machine was not initially numerically controlled, but a conventional milling machine with feed motors: we could work only one or two axes at a time by tinkering. I bought it, took it apart, cleaned it, then bought the entire CNC from China, meaning the screen, amps, cables and motors. Initially, it had three axes, then I bought a fourth axis and I had to tinker with a fifth axis to be able to make the carburetors (laughs), just with thought and common sense (laughs). It works well but the machine is old and had a little play, so this year I bought a small machining center which is more precise.
I also built myself a plastic injection press to make the gaskets and floats for the carburetors, because we couldn't find anything in this area. I'm self-taught but you learn by doing, and I did quite well. »
« On the other hand, we had to subcontract the gearbox pinions because special machines are needed, like at Micozzi in Italy. The carbon parts also come from Italy and the titanium exhausts were cut with a water jet by Arletti before being welded in a company in Maranello. »
For the general public, let's specify which motorcycles these are...
« We made replicas of the 2002 Yamahas, that is to say the last ones, but with previous generation engines, therefore with 56mm bore and 50mm stroke, while the last ones were 54x54. »
That's good, we won't accuse you of making fakes!
« We always wanted to be very clear on this, because this is something which, for me, is not admissible! Even if in terms of final value it may not make a big difference, there is no question of deceiving the buyer and there is no question of deceiving the public! They are replicas, and we built them from A to Z. And somehow, it is also a source of pride for us to have made them. »
Indeed, it’s crazy work, and this word will undoubtedly be used in the article…
« Yes, it's crazy work, but it's truly a passion, and our goal is to start the first of four bikes at the 2023 Sunday Ride Classic to be held on May 6-7 at the Paul Ricard circuit. We welcome all fans of mechanics and 500cc 2-stroke Grand Prix machines there! »
Thanks Claude!
Sunday Ride
May 6 & 7, 2023
Paul Ricard Circuit
Ticket presale: https://www.sundayrideclassic.com/billetterie
Pre-sale rate €18/day instead of €25 and on weekends €22 instead of €30 to see everything!
https://www.sundayrideclassic.com/
FB: https://www.facebook.com/SundayRideClassic/
Event : https://fb.me/e/3qG7hpvZJ
