For many years it was almost unheard of for a top MotoGP rider to request a change of crew chief.

The most famous partnership was that of Valentino Rossi and Jerry Burgess, which began when the Italian entered the premier-class in 2000. The pair stuck together during moves from Honda to Yamaha - winning seven titles along the way - then Ducati and back to Yamaha

But while Rossi won a race last season, he often struggled to match the MotoGP top three and decided that a change had to be made. Out went Burgess and in came Silvano Galbusera, who Rossi had briefly worked with when testing a Superbike while injured in 2010.

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It was, by Rossi's own admission, a big gamble. While he is yet to win a race this year it appears to have paid off. The Italian is third in the championship, compared with fourth last year, and has substantially increased his points and podiums.

Just as the Rossi-Burgess partnership was perhaps once a template for his rivals, rumours suggest that two other MotoGP stars - Jorge Lorenzo and Dani Pedrosa - could split with their longstanding crew chiefs, Ramon Forcada and Mike Leitner respectively.

Adding weight to the speculation is that neither rider has so far ruled out such a move.

"From my side I already answered in Brno after the race. It's the same situation," replied Pedrosa, who had previously spoken in general terms about the importance of the team.

Lorenzo's answer revealed that it may not be the rider who is seeking a change at Yamaha.

"It's just rumours I think. Also I hear a lot of things, that maybe Ramon has an offer from Suzuki or something like that. I don't know. For the moment it is just rumours. I think in a few weeks we will speak together with the team and decide what to make. For the moment I am happy with my crew."

Team-mate Rossi said that the personal nature of the relationship between rider and crew chief meant he could offer little advice to anyone else.

"I think that for me it is very difficult to speak about Dani and Jorge because it is a very personal decision," said the seven time MotoGP champion. "For me it was very difficult to make the decision because of almost 15 years together with Jerry.

"But unfortunately we were not able to find the way to improve the bike last year. For this reason, I thought inside that I had better potential and if I had a better setting I could fight with Lorenzo, Marc and Pedrosa.

"So I did this difficult decision but it is impossible for me to speak about them."