Imagine: Valentino Rossi and Maverick Vinales will be entered in the next Bol d'Or on their M1 Grand Prix which will not last the distance...
Would that be a crazy story? Certainly ! But it already happened, almost 40 years ago...
In 1978, Jean-Claude Olivier, the tireless and innovative manager of Sonauto, the importer of Yamahas in France, decides to take on the crazy challenge of entering a 2-stroke Grand Prix motorcycle in a 24-hour endurance race!
There have already been a few attempts in previous years, but this time, the participation of the Yamaha OW 31 will be official, and with the star riders that are then Patrick Pons et Christian Sarron.
Driven hard, the Iwata machine can barely hope to reach the halfway point, mainly because of its connecting rod assembly which is not designed for such long distances.
Its preparation is nevertheless entrusted to Christian Maingret and essentially consists of careful assembly of the engine after changing the crankshaft bearings and having the cylinders treated with Nickasyl (Nickel Silicon Carbide). The exhaust pipes are reinforced to resist vibrations.
On the chassis side, we mount a swinging arm allowing faster rear wheel changing, Brembo calipers for the same reason at the front, a tank with a Zenith valve, two headlights outside the fairing and a battery, since the engine obviously does not have an alternator. The battery will be changed at each refueling…
During qualifying practice on the Paul Ricard circuit, the Yamaha #5 of Patrick Pons/Christian Sarron obviously achieved pole position with a time of 2'08.47, 4 seconds ahead of the Honda 1000 RCBs of Jean-Claude Chemarin/Christian Léon et Jacques Luc/Hubert Rigal. Everyone knows, however, that this does not bode well for the future...
other Yamaha OW31 appear at the start. That of the privateers Roche and Agopian in 4th place in 2'14.25 and that of the Gras/Coq crew who will start 6th. Further on, we still find that of Renaudat/Guilleux…
At 15 p.m., after an average start, the Yamaha of Pons and Sarron took command shortly before the end of the first hour of racing. She begins to escape inexorably by adopting a pace between 2'15 and 2'17.
At this moment, the one piloted by Agopian falls. Roche sets off again but finds himself without brakes following a broken lever... big scare!
The first retirement of an OW31 came at the end after 3 hours of racing, with the #23 bike of Renaudat/Guilleux. In the lead, number 5 purrs…
At 22:30 p.m., the crankshaft of the Yamaha of Bourgeois and Soulas gave up the ghost... it was abandoned after 161 laps. In the lead, number 5 purrs…
We enter the night without knowing if the blue and white OW31 will emerge. At midnight, she was 3 laps ahead of the Honda of Chemarin and 10 over the Japauto of Fonta and Villa.
The hours pass, the men tire, and when the sun begins to rise, oh miracle, the Grand Prix machine is still in the lead! The crankshaft has a theoretical lifespan of around ten hours but it withstood the halfway point.
In the Sonauto clan, we are starting to believe it… Among enthusiasts who listen on their “transistor” to the timetables broadcast by France Inter, too!
Unfortunately, a few minutes later, the reality of the race came to call all 2-stroke fans to order with the abandonment of the OW31 from Roche and Agopian, broken crankshaft after completing 303 laps...
On number 5, Pons and Sarron are now clenching their butts because, although still in the lead, they know their hours are now numbered...
At 8:43 a.m., after having completed 436 laps, the brave 2-stroke fell silent, crankshaft out of service after screaming for 17:30 hours, the distance of a good twenty Grands Prix! The machine is parked along the rail in the straight line of the Mistral...
Among the men in blue, we are obviously disappointed, but we promise to come back. And we will come back. With two machines the following year for Patrick Pons/Sadao Asami and Hubert Rigal/Raymond Roche, then three in 1980 for Roche/Lafond, Rigal/Van Dulmen and Asami/Kinoshita!
But this is another story that we will perhaps tell you one day…
Only one OW31 reached the finish line that year, that of the Patrick Lefèvre/Didier Dalet crew. Equipped with a Spondon frame and a lower engine pampered by Jacky Germain, it crossed the line after 470 laps and 2730 kilometers, 24th and last.
Christian Sarron tells us today: “It was my second Bol d'Or because I had already participated in it for the Godier-Genoud team with Denis Boulom, as reward for my good result in the Kawasaki Cup. But there, it was completely different because our bike was a 2-stroke. This was the bike I usually rode in the 750cc world championship, finishing second to Steve Baker in 1977. Unlike the latter, it was not a factory bike and had been slightly deflated before be equipped with its accessories for endurance.
What struck me the most? This is because we spent a lot of time in the pits because of fuel consumption and tire wear, but as the bike was much faster than its competitors, and we came from the world championship, we spent our time zigzagging on the track between the competitors. With Patrick, we were a bit alone in the world in our adventure! From memory, it seems to me that when the bike broke in the early morning, we were 17 laps ahead…
In one way, it was difficult and quite boring.
Honestly, at the beginning we didn't believe in victory at all. No one on the team believed it, but when we got through the night and the bike was still working well, we almost started to hope...
So obviously, it was a big disappointment when the bike broke, because we had done a little more than two thirds of the race. »
Where is this amazing motorcycle today?
It was resold several times and ended up in the hands of an individual who entrusted it to drivers for classic endurance races. After several falls, unfortunately there is almost nothing left of the original motorcycle: destroyed polyester, twisted frame, burst engine casings, etc... Sad fate! The others (1979 and 1980) fortunately survived.
Sources and credits: Yamaha-community, Bike70, General classification (Vincent Glon), FIM-Live.com, etc.
