Sepang:Having opted to miss the recent MotoGP test session at Phillip Island in Australia, Yamaha will be looking to make the most of this week's gathering at the Sepang Circuit. Valentino Rossi is one of seven drivers from four teams taking part in the sessions, where the challengers for the forthcoming MotoGP season will be put through their paces. For the 2007 season, Rossi will be riding the 800cc M1, which the Italian and Yamaha hope will be powerful, and reliable, enough to reclaim the riders' and constructors' titles. Rossi was unseated from his throne in 2006 as American Nicky Hayden claimed a maiden MotoGP title. With his compatriots Marco Melandri and Loris Capirossi in the thick of the action and young Spaniard Dani Pedrosa continuing to impress, Rossi will need all the power that he can find if he is to force his way back to the top of the world standings in 2007. 'The Doctor' clearly believes that Yamaha can deliver a competitive package as he has recently signed a contract extension that will see him race for the team until the end of the 2008 season. A five-time former premier class champion, Rossi has picked up two championship titles and 25 grands prix wins during his three seasons with Yamaha. With the Sepang Circuit famed for its variable conditions, the attending riders are guaranteed an informative time in Malaysia this week. The official pre-season testing schedule concludes at Jerez in Spain on February 25th, while the new season gets underway with the Grand Prix of Qatar on March 10th.