Estimated reading time: 5 minutes
We open our story in 1975. A 250cc reverse cylinder Yamaha housed in a Jack Germain frame was developed for owner and rider Gérard Choukroun. His mechanic was Phillipe Berthelin who built the engine. The bike used many Yamaha parts including the engine, forks, Mikuni Yamaha carburettors, wheels, tank, seat and radiator.
Yves Kerlo, a former French Championship 125 rider, worked alongside Berthelin to help develop the exhaust system. Kerlo and Berthelin remained involved in the unusual machine and were instrumental in the restoration undertaken by the current owner Phillipe Torollo in 2000. Torollo still owns the bike today.
↑ Gérard Choukroun and Phillipe Berthelin, at the 1975 French 250 Grand Prix © Michel Montange. Picture two features Jean-Claude Olivier the French Yamaha boss at the time. Picture three shows Choukroun riding in the 1975 Le Castellet French GP, the final picture with Patrick Pons, Phillipe Berthelin and Gérard Choukroun on the bike © Yves Kerlo.
Following the 1975 season the Germain frame was replaced with a standard Yamaha chassis and the bike was sold. The special parts along with the bespoke frame remained with Berthelin until he passed away in 1987. Phillipe Torollo purchased these unique parts in the early 2000s with the aim of rebuilding the bike once again using another engine but all the other parts as per the original. Yves Kerlo returns to the story to help with the rebuild and recreating the exhaust pipes.
Torollo still owns this special machine today and the following photograph is the restored bike. It was used in 2007 at Moto Legendes.
↑ Image supplied by Yves Kerlo
The French revival in 1979
We pick the French reverse cylinder story back up again in 1979 with another completely different machine built and owned by Jean-Bertrand Bruneau with help from others at the time. They built three machines, two 250s and a 350cc version. All used Yamaha TZ engines with special parts and features including experimental carburettor angles. Jacques Bolle was selected to ride them all during 1979 but they were never used again.
Jean-Bertrand was a prolific builder and created 40 specials from 1971 through to his death in November 2020. Although not part of the original ’79 project, Yves Kerlo became involved in the restoration of Bruneau’s collection, including the 250 reverse cylinder machine in 2020. The bike is still owned by Bruneau’s widow and is stored safely in Kerlo’s workshop.
↑ First image: Jacques Bolle on the 350cc version during practice in the UK. These radical exhausts were banned by the race organisers! © Christian Bourget
↑ Second image: 250cc machine from the back © Michel Vossen. Plus a front view of the Lectron carburettors © Yves Kerlo.
↑ Third and fourth images: The 250cc machine as it is today – fully restored and owned by the Bruneau family. © Yves Kerlo
↑ First image: Jean-Bertrand Bruneau’s design drawing of the machines he would go on to build.
↑ Second image: Jacques Bolle at the 1979 French 250cc Grand Prix. © Christian Bourget.
↑ Third image: The restored bike without the fairing.
