Valentino Rossi improved both his lap time and position during day two of the Sepang MotoGP test.

The Italian finished fourth quickest the second fastest (updated) Yamaha rider behind new team-mate Maverick Vinales and 0.8s from new Suzuki signing Andrea Iannone.

"In the end it was a good day, because this morning we lost a lot of time waiting for the track conditions," Rossi said of the damp start. "We did more than 50 laps. We had some important stuff to try and more-or-less everything was quite positive. My pace was quite good and at the end I do one time attack and I am in fourth position."

While a radical new fairing, designed to replicate some of the previous winglet performance, grabbed much of the attention, Rossi emphasised that work on a new M1 frame was more significant.

"More important than the fairing was the different frame. It was good, I like it. We have not decided yet, but the first impression was positive," he explained.

"It is easier to ride the bike. We try to have an easier bike and, especially, during the second half of the race put less stress on the tyres. I feel good. Tomorrow we will continue to do a comparison from one chassis to the other and decide [which is best]."

Given the encouraging form of the Yamaha, Rossi was asked if he might be able to capitalise on potential difficulties for fellow world champions Jorge Lorenzo and Marc Marquez. Former team-mate Jorge Lorenzo improved from 17th to eighth for Ducati on Tuesday, with reigning champion Marc Marquez dropping one place to tenth for Honda.

"I'm sure Lorenzo will be ready to try and win in Qatar, because already today he was fast. He was not so bad and did some good laps," Rossi declared. "Speaking about Honda - and especially Marquez - we have to wait tomorrow at 6pm because for sure today he worked with use tyres, long runs and he 'hide'! But I'm not surprised if tomorrow he puts the new tyres and give half-a-second to everybody.

"About us, I'm happy, the bike is good. Is very beautiful and I feel good and looks like also in the straight it is not so bad, so it looks like we have a good potential this season."

Rossi added that he did not try any of the new Michelin tyres available today.

"We decide to do tomorrow. I know from the other riders they find something good in the front. We hope the conditions are good and I will try tomorrow."

By Peter McLaren