Fabio Quartararo's frustration with Yamaha's performance was evident at the Buriram test, where he ended 18th among 22 riders, more than 1.2s off the pace set by Gresini's Alex Marquez.
What happened at the Buriram test?
The Frenchman returned to action on Saturday after missing most of the Sepang test due to a finger injury, but his first day back at the track proved to be frustrating.
He even showed the middle finger to his bike, and was later seen with his head in his hands in the Yamaha garage.
Why the frustration for Fabio Quartararo?
Team manager Massimo Meregalli acknowledged that the team is undergoing a learning process with the new V4 engine, and that the riders cannot wait for improvements.
Meregalli recalled the scale of the task undertaken by Yamaha in switching to a brand new engine this year, saying "we knew since the beginning that we couldn't expect magic".
The team had to pause its testing programme for a day in Malaysia due to an engine-related safety issue, and is exercising caution with the V4 due to reliability concerns.
What comes next for Yamaha and Fabio Quartararo?
Meregalli denied that an upgrade to the V4 engine will happen at the start of the championship, saying "it's later in the season" and that the team will start the season with the current material.
Pramac rider Jack Miller led the four-bike Yamaha contingent in 17th, but his time of 1m30.325s was less than two tenths faster than Quartararo's best effort.
The Buriram test results showed that Quartararo has a lot of work to do to catch up with the leaders, and that Yamaha's performance is still a concern.
As the season approaches, Fabio Quartararo and Yamaha will be looking to improve their performance and compete with the top teams in MotoGP.