Even now Randy Mamola struggles to comprehend the incredible journey he has taken with Riders For Health. He arrived in England as a fresh-faced Californian boy amid a world of black-clad bikers with lamb-chop sideburns but ended up walking down the pitlane in the Netherlands with the Princess Royal. “I’ve had a lot of heroes in my life but the real hero has always been the motorcycle,” he said.

Mamola was a star in the 1980s when he was runner-up four times in the 500cc World Championship. Regarded by many as the best rider never to win the title, he cultivated a reputation as a maverick and crowd-pleaser, once crashing on the warm-up lap and then pulling a front wheelie, known as a stoppie, during the 1986 French Grand Prix, an act deemed irresponsible enough for Kenny Roberts, his team manager at Yamaha, to sack him.

Roberts later relented and reinstated Mamola, who also showed a softer side when, after a political squabble between the riders and motorcycling officialdom, he handed over $20,000 to the Save The Children Fund, initiating his partnership with the Princess Royal, the charity’s president. “In the old days we didn’t earn a lot of money,” Mamola, now a MotoGP tele-vision commentator, said. “You might get $5,000 for winning a grand prix. We did a deal to get a lot more, but I wanted to give my raise to charity.”

It was three years before Mamola went to Somalia to see how his support was helping. That was a life-altering trip for him and Barry Coleman, a friend and former journalist. They saw discarded motorcycles littering the dusty vista. Intended to be used by health officials, they were terminally damaged. “We thought, ‘what if we could fix them?’ ” Mamola said and Riders For Health was born. The number of projects has since spread, with the aim always being to fix Africa’s crumbling transport infra-structure and get medical supplies to the people who need them the most. The drugs don’t work if the bikes remain broken and so Riders For Health trains local African health workers in the art of motorcycle maintenance.

The unique aspect to Riders is how it has been adopted by the entire motorcycling community as its charity of choice. “There’s nothing like it in any other sport,” Mamola said. The top stars, such as Valentino Rossi, the seven-times world champion, clamour to help. Some, such as Kenny Roberts Jr and Marco Melandri, have been to Africa to see the work in progress. “Professional sports people can have a very narrow focus and we wanted them to see what was going on,” Andrea Coleman, Barry’s wife, Riders co-founder and a former racer, said. Nicky Hayden, the 2006 champion, dropped his trousers on stage at one of the charity’s auctions and sold them. There is little people will not do.

It was not always like this. In the early days of this charity, organising auctions and paddock visits at grands prix, was deemed “a nuisance”, according to Andrea. Some stars, such as Kevin Schwantz, the 1993 champion, leapt at the chance to work for the charity. Others, such as Eddie Lawson, the legendary four-times champion, took more persuading.

Mamola has always been the figurehead and pinpoints the Princess Royal’s visit to Assen in the Netherlands, always one of the more raucous biking weekends with burning tyres in the campsites and fabled tales of debauchery, as his highlight. “I remember seeing her walking down the pitlane and chatting away to Mick Doohan,” he said. “I started out riding in a dirt field next to my home and now I was mixing with royalty because of the things a motorcycle can do. It was hard to believe.” Mamola has since been invited to Buckingham Palace and the Princess Royal is the charity’s patron.

Riders For Health has also, in its own way, restored the reputation of the motorcycle fraternity. Often regarded as outsiders, their adoption of the cause has revealed a rich vein of good running through the sport from top to bottom. In another way it also helped to redress a tragic imbalance.

In Mamola’s era and beyond, the risks were manifold and deaths were common. Coleman’s first husband, Tom Herron, was killed racing in the North West 200 in 1979, while Wayne Rainey, one of the mainstays of the Riders clan, was on his way to a fourth successive world title when he crashed in the Italian Grand Prix in 1993 and broke his spine, leaving him paralysed. “The motorcycle gets a bad press sometimes, but it is saving lives and that is a beautiful thing,” Mamola said.

CVC Global Partners, the private equity group, will match donations from readers made to Riders for Health. That means for every pound donated, Riders for Health gets £2.