Rossi is heading off on holiday after trying out his new bike

"Not every part of this prototype bike is new, but Yamaha has changed a lot," said Rossi after three days' work.

"We are aiming for more stability in the rear end, but we want to keep the sweet handling.

"We are also looking for a little more horsepower as everyone knows, which is one area we need to improve on."

The Italian and new team-mate Colin Edwards worked together on the new bike at the Sepang track in Malaysia.

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"Yamaha has put in a lot of effort to bring this bike here and enable us to start work on it in the right direction for next year, so it was very important for me to be here," said Rossi.

"We're still not quite there yet, but Yamaha's engineers will continue this work during the winter and then I am sure we will be nearer our goal when we meet again in January. I'm now looking forward to a long holiday."

A winter test ban is now in force until the new year, and the next round of testing will begin at Sepang on 22 January.