LE MANS, France - Double MotoGP World champion Casey Stoner said on Thursday he’s lost his love for the sport and will retire at the end of the 2012 season.The 26-year-old Australian won the 2007 crown for Ducati and the 2011 title for Honda and currently leads the World standings by one point from Spaniard Jorge Lorenzo heading into the fourth race of the season this weekend in France.‘DIFFERENT THINGS IN LIFE’"After a long time thinking, a lot of time talking with my family and my wife, this has been coming for a couple of years now," Stoner told a news conference at the French circuit."I will be finishing my career at the end of this season in MotoGP and go forward in different things in my life."After so many years of doing this sport which I love, and which myself and for which my family made so many sacrifices, after so many years of trying to get to where we are at this point, this sport has changed a lot and it has changed to the point where I am not enjoying it."I don't have the passion for it so it's better if I retire now."Stoner moved into the premier category in 2006, claiming his first pole position in only his second start in Qatar, and the following year won his first MotoGP race at the same venue before going on to take the 2006 championship.‘THINGS DISAPPOINTED’He was runner-up in 2008 but missed a number of races the following season with a mystery illness and his fortunes only changed when he switched to Honda for 2011.Stoner was on pole position 12 times on his way to a second World title."There are a lot of things that have disappointed me and a lot of things I have loved about this sport... but unfortunately the balance has gone in the wrong direction," he added."It would be nice if I could say I would stay one more year but then where does it stop? So we decided to finish everything as we are now."