MotoGP 09/10's recent 2010 Season DLC were likely miffed by an unintended side effect of the update. Apparently, players who completed the game's 2009 Season couldn't access the new competitions or bikes without being kicked to the main menu. Even worse, upon returning to their 2009 careers, players would realize their precious motorcycles had mysteriously vanished into thin air.
Capcom recently apologized profusely on Eurogamer, stating, "we are aware of the problem and are working to deliver a solution to solve the issue as soon as possible." In the mean time, you might want to keep on living in the past. Sure, the bikes are a bit outdated, but at least they exist.