While his new team-mate Maverick Vinales was topping the timesheets, Valentino Rossi spent the second and final day at the Valencia MotoGP test evaluating the latest Yamaha developments.
Second quickest behind Vinales on day one, Rossi was seventh on the Wednesday timesheets, 0.734s from the young Spaniard's 1m 29.975s best.
"Today we made a lot of laps  and we compared the new bike with the old bike, the new engine with the new chassis. We have a lot of work [to do] for sure, especially about the engine, but also about the chassis," Rossi said.
"The first feeling with the chassis is good, but it needs something different in the setting. So we need a little bit more time to understand the balance. But next week we will have another test, in Sepang, a completely different track."
Asked to pick the most important area to improve, Rossi - who was 13th on the top speed charts - stated: "We have to concentrate on the engine, in acceleration. Try to have a good exit from the corner.
"The feeling with the engine is very similar [to yesterday]. Is just the first step, but the first impression is not a huge improvement so we need to work. I hope that for Malaysia I will have some other stuff."
While Yamaha will test at Sepang next week, their rivals will take part in a private test at Jerez before the winter test ban begins on December 1.
By Peter McLaren