Unfortunately, all-important race pace proved much more 'frustrating' for the American - who is also still swapping between the pneumatic-valve and 'conventional' engines.

"We ended up not too bad but it'd be nicer to be faster on race tyres," said Hayden, the only Repsol rider at the test following Dani Pedrosa's recent hand injury. "To be honest, it's been a frustrating couple of days here. We got into the 31s about the fourth exit from the pits on the first day and really we haven't been able to go any faster since then, except with the qualifiers, which were good.

"We've chased our tail a bit and I haven't really found a batch of race tyres I like. I struggled a lot when I was here for last year's race, but I did find something I liked. I didn't have that option this week, so I can't say I'm completely happy with the combination of bike, rider and tyres.

"We tried the pneumatic-valve engine and the conventional spec engine in the new chassis at this test. We did a lot of tyre testing with Michelin using the conventional engine.

"The chassis did some good stuff but not enough through this fast stuff here. We left Sepang last week in a positive way and it's still early days, there's a lot of work still to be done. Now we go back to Sepang for two days, we've got a few days off and then keep trying to chip away at it," concluded the 2006 world champion, whose best soft tyre lap was 0.957secs behind Stoner.

Hayden and Repsol Honda will test at Sepang next Tuesday and Wednesday.