American Ben Spies said he has been inspired by the new 1000cc YZR-M1 Yamaha after his first ride on the machine at Sepang today.

Spies, who won his maiden MotoGP race last year, quickly got to grips with the 2012 factory Yamaha in Malaysia, ending the opening day of the official test with the fourth fastest time behind team-mate Jorge Lorenzo, Repsol Honda's Dani Pedrosa and Britain's Cal Crutchlow (Yamaha Tech 3).

His fastest lap was 2m02.234s compared with 2010 champion Lorenzo's best effort of 2m01.675s.

Spies said: "I'm happy, it was fun to get back on the bike today, I haven't ridden any type of motorcycle since Valencia. It didn't take too long to knock the rust off, we tried a few things in set up and every step we did made small improvements.

"We have a lot to do in the next couple of days and a lot more in the second test. It's been a confidence-inspiring start, Yamaha have put in a lot of effort for this season so we'll work day by day to be even better."

Spies and Lorenzo will compare a variety of new settings over the next two days of the test before returning to Sepang for further testing in March.