Rossi "not optimistic" if Yamaha can't solve electronics woes

The Italian, who turned 39 on Friday, struggled for much of last season with a lack of feeling from the M1's chassis and poor traction – an issue which returned on the first day of the second pre-season test in Thailand.

Rossi admits Yamaha has been on the back foot ever since the championship switched to Magneti Marelli's control electronics software for the '16 campaign, and says Honda and Ducati “understand” the system better than the Iwata-based marque.

“When we move to the Magneti Marelli [control software], for me we have some problems,” the Italian revealed. “So for us, is difficult to understand.

"Honda and Ducati understand something we don't understand. So I hope that we can recover as soon as possible, because at this moment we suffer. For me, it's this.

“The good thing of the electronics is it's not the engine, or the chassis, or the swingarm [which is causing the issue]. You can fix with a number, so you can fix in a shorter time.

“But I'm quite worried, because if we don't fix now I'm not optimistic to fix for the first races. So I don't know what we have to do.”

Pressed as to whether focusing more on the electronics could have salvaged his '17 campaign, Rossi remarked: “[They are] two different things, both. Electronics, Ducati and Honda improve a lot during the season, and in the second part were stronger.

“Another thing is the chassis. Now, when I brake and entry into the corners I feel good. But we need more acceleration.”

Rossi ended the opening day of testing at the Buriram track eighth fastest – 0.392s off pacesetter Cal Crutchlow on the LCR Honda – and has a feeling “more similar” to what he had on the '16 M1 despite his continuing troubles exiting corners.

“For me, the bike is better than last year, I feel better,” he added.

“I have the feeling more similar to two years ago, and this is very important because I suffer a lot last year, maybe more than Maverick [Vinales] with the 2017 chassis.

“But for me, at this moment, all the Ducati [riders] are better at acceleration because they are more in front than us with the electronics.”

Additional reporting by Oriol Puigdemont