Yamaha is struggling ahead of the new MotoGP season, according to riders Valentino Rossi and Maverick Vinales.
Italian great Rossi and his teammate made the comments after the latest round of tests were completed in Thailand.
The nine-times world champion was 12th following the latest test while Vinales was in eighth spot.
At the last test in Malaysia, Vinales was seventh while Rossi was ninth.
The team struggled with grip problems during the second half of last year and the recent tests have done little to raise hopes that the problems have been solved.
“It was a difficult test, we struggled and we have to improve because we didn’t improve a lot compared to last year,” Rossi said after the tests at Buriram. “Especially with the electronics, so I think we have a lot of work to do.”
“I think that we improved today. I rode a 1’30.5s, but unfortunately I made a mistake at the end of a really good lap, else I could have done a 1’30.2s, and we’re all very close.
“Like last year, it’s difficult to understand where we stand. A lot of people were strong in Malaysia and here they struggled, and also the opposite. We have to improve, because we didn’t make much progress compared to last year, especially when it comes to the electronics.
“We have a lot of work to do and at this moment we have to get through it – but that’s today, maybe in Qatar it will be better.”
“It’s been a difficult test, like it was in Malaysia. We are working hard trying to figure out what the problem is – right now mostly on braking, but we have to improve in all areas,” said the Spaniard.
“We have to continue working, trying to find out how to improve. The race days are coming up fast and we only have the three days in Qatar left. I will keep working and I will be 100% ready, and when the bike is ready I will push.”