Yamaha test rider Augusto Fernandez has claimed its V4 engine is “still not fast enough” with the Japanese marque hoping to use it for the 2026 MotoGP campaign.
The organisation has been developing the new power unit since last year, with Yamaha being the only MotoGP manufacturer to use an inline four rather than a V4.
That has seen a correlation with performance as Yamaha, a previous dominant force, is currently bottom of the 2025 constructors’ standings after 11 rounds.
So Fernandez, who has been entered for this weekend’s Czech Grand Prix, recently completed a private test at the Brno Circuit to continue the engine’s development.
"It's looking good, it looks very positive and everything but it's still not fast enough," said Fernandez, who joined Yamaha this year.
"It's what will decide [the engine] for next year. Let's see if in the next months during this summer, we have some more tests to try to accelerate the process and have the bike ready for the end of the season.
"We need to accelerate the process because if we want to race with the V4 next year, we still need to do a lot of work.
“The last test wasn't the full package still, the engine is not the full [power] one. Everything is just very early for everything."
But Fernandez explained that Yamaha engineers at the Japanese factory are opting for a more gradual process with the development.
"The engine is not at its full performance from Japan," he added. "They [the engineers] don't give us all the power from the engine, but if they understand the process, it will be good.
“At some point, we will need to see which one is faster in terms of lap time. It's what will decide [which engine to choose]. It's not a negative, but we just need to see better lap times.
"They want to understand it without breaking it. They give us [performance] little by little. In Japan, things are like that. They want to understand everything very well. Nothing against that as long as we have a good bike for next year, but it's going well so far."
