Kawasaki and Suzuki have raced with pneumatic-valve engines - as used in Formula One - since the start of 2007, while Yamaha is now working flat-out to have its own system, used off and on by Valentino Rossi during the second half of last year, ready for the start of this season. Ducati's MotoGP engines, like its road bikes, use a desmodromic valve system.

Turning back to the 'standard' engine/2008 chassis with which he set his best lap time, the Repsol rider explained that they were able to substantially improve the front end problems experienced on day one.

"We worked on set-up of the bike a little bit; changed some springs and got a better feeling in the front. Also I tested some front tyres I liked better. My feeling with the bike improved today, so I'm happier than I was yesterday by a long way," he said.

"I did a long run at the end and did my best lap ever here, on a race tyre, on lap 18 of my long run. It wasn't a spectacular lap, but at the end of three long days it wasn't a bad time, so we're pretty encouraged by it."

That lap, of 2mins 1.716secs, was 0.752secs behind the best race-tyre lap of the day, set by Ducati's reigning world champion Casey Stoner, who also recorded the second fastest overall lap time after a qualifying attack placed the Australian 0.334secs from Hayden.

Yamaha's rookie Jorge Lorenzo was third (+0.440secs) with his Michelin-shod M1, while Yamaha Tech 3's Colin Edwards was fourth (+0.853secs) - on a race tyre. Edwards' best race-tyre lap was just 0.2secs slower than top Bridgestone rider Stoner.

New Kawasaki signing John Hopkins claimed fifth position, 0.872secs from the top, while Valentino Rossi had to settle for sixth (+1.099secs) on his Bridgestone-backed 'pneumatic' M1, three places behind Michelin-shod team-mate Lorenzo.

Lorenzo's former 250cc rival Andrea Dovizioso was seventh (+1.121secs) for JiR Team Scot, with fellow rookie James Toseland eighth (+1.419secs) and ahead of Rizla Suzuki team-mates Chris Vermeulen (1.422secs) and Loris Capirossi (1.452secs).

Edwards, Vermeulen and Capirossi were the only riders in the top ten to set their best lap times while using race tyres.

Hayden's team-mate and 2007 MotoGP runner-up Dani Pedrosa missed the last two days of the test after fracturing his hand on the opening day. The Spaniard has already had a plate inserted to help the injury heal and is certain to miss next week's Phillip Island test.

"For me, nothing changed at this test," said Hayden, when asked if his schedule was adjusted following Dani's fiery fall. "Maybe [Pedrosa's absence] might change some things at Phillip Island."

The Phillip Island test takes place from January 30 until February 1.