Nicky Hayden was able to gain more edge grip during day one of the February Sepang MotoGP test, which the 2006 world champion finished second fastest out of the nine riders present.

With much of Repsol Honda's pre-season focussed around its engine choice, with the all-new pneumatic-valve engine still being run alongside the standard spring-valve unit, Hayden switched tact and spent day one in Malaysia focused on chassis comparison testing while using a variety of front and rear tyres from Michelin.

Team technicians tried slight geometry variations that improved the overall balance of his factory RC212V and provided Hayden with better rear end grip, particularly on the edge of the rear tyre... although Nicky still suffered a small fall at the final turn late in the day.

"We got a late start because the track was not in good shape after the overnight rain. Nobody was in a hurry to go out. When we did we all went together and cleaned up the track a little," explained the American.

"We ran comparison chassis tests and confirmed what we learned at Phillip Island. The guys changed the geometry a little on the 2008 chassis and the bike had a better balance so we made some progress there.

"Michelin gave me a couple of rear tyres I really liked, one 16 inch and one 16.5 both have good grip on the edge of the tyre and the bike felt a lot better! We will keep on working on the chassis tomorrow and test more tyres," he added.

Hayden finished day one half-a-second behind Valentino Rossi on race tyre pace, although the Italian pulled 1.6secs clear after a late qualifying tyre lap.

Repsol Honda team-mate Dani Pedrosa isn't present at the test due to a fractured hand, sustained at Sepang in late January.

The 2007 MotoGP World Championship runner-up hopes to return to action next time out at Jerez, from February 16-18.

The third and final Sepang winter test continues on Wednesday.