Rossi fears Yamaha fix could take 'several months'

Rossi conceded after the opening day of last week's Thailand test that he was "not optimistic" for next month's Qatar Grand Prix season-opener as the acceleration problems that plagued his 2017 campaign were still present.

The Italian blamed this issue on the bike's electronics, but says trying to fix the problem is difficult due to the bike's constant change of performance from day to day at each circuit so far - and is not convinced Yamaha will have a solution for the final test at Losail next week.

"The big problem is that you never know what to expect, it's like playing cards," Rossi, who was 10th and 0.730 seconds off the pace after Sunday, said.

"And everyone is very strong and very close. The situation from last year has come back, that you don't know what can change between the morning and the afternoon, let along from day to day.

"It's a very strange situation, which only happened to me last year in my career. Even though we already had the Michelin tyres, the performance was more consistent.

"Since last year, everything can change in a moment. It was a difficult test for Yamaha, I was happier in Malaysia than here, we hope things will get better in Qatar.

"We know we have to work mostly on the electronics, but I don't think there will be anything new on that in the next test in Qatar.

"This is something that could take several months [to fix]; until then, we are relying on fate."

After the first two tests, Rossi believes only Honda - whose three factory riders topped a day each at Buriram - has so far built a bike that is consistently competitive at different circuits.

"From what I understand, the only manufacturer competitive in both tracks was Honda," he said.

"Especially with Marc [Marquez], but also with Dani [Pedrosa] and [Cal] Crutchlow.

"Also Ducati were flying in Sepang, [Jorge] Lorenzo was first in Sepang and here he is struggling.

"So we have to wait till Qatar to see what happens."