A hectic initial day of testing for the official MotoGP competitors finsihed at the Sepang International Circuit on Thursday, as work on this season's prototypes continues.

Fiat Yamaha’s Valentino Rossi claimed the quickest time of the track out of 17 racers, the Doctor’s time of 2’01.411 on the fresh M1 was only just under a second off the pace (2’00.518) which gave him pole spot last year at the circuit.

Casey Stoner’s Ducati Desmosedici GP10 was cleared by a gap of 0.491s, as the Aussie gave 42 laps altogether. The Ducati Marlboro squad are testing clean fresh forks and two fairings, both were used in the last four events of 2009.

Colin Edwards was happy with his session on the M1 of the Monster Yamaha Tech3 squad. The American was the third and last racer to come in under the 2’02 mark, with a best time of 2’01.932.

The initial rider out on circuit for the day ahead was Loris Capirossi, who arrived at 9.07am. The Italian came in as the fourth fastest lap of day one, his 58 laps gave a time of 2’02.102. The Suzuki squad has three chassis's to test for the competitor, while the new motor will be due at the following Sepang test at the end of February.

Jorge Lorenzo turned 57 laps to set a time of 2’02.165, he also raced the new M1. He ended the day with a 0.754s gap to colleague Rossi.

Repsol Honda are testing their fresh bike with some amendments to the chassis. Their motor, which has been enhanced for better endurance, and new electrics are being trialled by Andrea Dovizioso and Dani Pedrosa, they arrived sixth and eighth respectively. The Italian was 0.465s after Lorenzo, with Ducati Marlboro’s Nicky Hayden in seventh spot with 2’02.792.

Mika Kallio’s initial experience with the Desmosedici GP10 for Pramac Racing came in just under the 2’03 mark, he finished 70 laps and was ninth on the time card.