Valentino Rossi says he prefers the new chassis Yamaha brought for him to try in Monday's Barcelona post-race test, as it suits his riding style more.
Since pre-season testing, Rossi has struggled to get the 2017-spec Yamaha to his liking, complaining of understeer and a lack of rear traction in last weekend's Catalan Grand Prix.
Both factory Yamaha riders struggled in Barcelona, with Rossi coming home eighth and Maverick Vinales finishing 10th, and the team brought a pair of new chassis to try in the Monday test.
With his new frame, Rossi finished the day 10th-fastest, and will sample the other type on Tuesday in a straight swap with Vinales as the Yamaha riders stay on in Barcelona for a private test day alongside riders from Suzuki and KTM.
"I always struggle with this bike in turning and for the entry of the corner, I am never 100 percent comfortable," Rossi said.
"Today we had a little bit different chassis, Yamaha always works a lot on this point and it is better, I like it. I prefer the bike like this, it is easier and better for my style.
"The bike turns a bit better and I can enter the corner faster so this is the way I prefer you can be more precise also it is more fun to ride.
"Some other problems still remain, like the stress on the rear tyre, [but] that anyway is quite a lot in a track like this."
Vinales confused about sudden improvement
Rossi's teammate Vinales, who struggled all weekend in Barcelona, was second in the test with his chassis, as the championship leader "felt confident" again.
However, the Spaniard admitted was confused why the sudden improvement happened.
"Honestly no [idea], since the beginning when I enter the track I felt so much better," said Vinales.
"I feel good again on the bike, after Friday, Saturday and Sunday with no good feeling today [on Monday] I felt good again.
"I was riding really good also as I was feeling confident I could push a little bit more with the bike on the limit and it was nice to ride good again."
Rossi: Vinales doesn't know old Yamaha
In contrast to teammate Rossi, Vinales enjoyed an impressive start to his Yamaha tenure in pre-season testing, going fastest at Sepang, Phillip Island and Qatar.
When asked whether Vinales' strong start to the season made Yamaha complacent, Rossi reckons his teammate only liked the bike because he didn't know the old one.
"Maverick was fast and he continued to like [the bike]," said Rossi. "He is the guy with more points so I have to speak more about me, I am coming from another story.
"Maverick doesn't have any history with Yamaha before coming from Suzuki.
"He likes this because he thinks this is the Yamaha, but for me that I know more of the evolution of the bike I think with the 2017 version we lose something.
"Yesterday [in the Barcelona race] he was also in trouble, but I think he can go fast anyway."
Additional reporting by German Garcia Casanova