MotoGP champion Casey Stoner says there is still some work to do ahead of Sunday's race despite dominating Friday practice in Valencia.
The 22-year-old Australian, who wrapped up the championship in Japan in September, posted the fastest times in both free practice sessions, improving his morning time in the second session to clock 1:32.968 on his Ducati for the four-km lap of the tight and twisty Ricardo Tormo circuit near Valencia.
Stoner, looking for his 11th victory of the season this weekend, was pleased with his day's work, but admitted there are still improvements to make.
"Everything seems to be going pretty well again," said Stoner. "We tried a lot of different settings this afternoon to try and make the harder compound rear tyres work, because the conditions are a bit colder than we expected.
"The tyres we have prefer to work in slightly hotter temperatures, so we're going to have to make them work a bit harder. A lot of times today we had new tyres on but the setting wasn't quite right so we weren't able to do good lap times, then we'd improve the setting using old tyres and we were able to go very fast.
"We just need a little bit more work on the set-up and we should be able to get pretty close."
Teammate Loris Capirossi was unable to match Stoner's pace, finishing down in 14th position after complaining about a lack of traction.
"We are working hard, trying to get better rear traction," he said. "We have three types of rear tyre, all a bit too hard for what I need, so we will probably adjust the set-up to put more weight on the rear.
"Last year we found a good set-up here but the bikes are very different now - you use the edge of the tyres a lot more with the 800s and this can make things difficult for my riding style.
"Anyway, we will see what we can do with the set-up, and if we do find more traction it should be easy to go five or six tenths faster."