According to the rules, manufacturers must homologate a fairing before the start of the season, and they must do so before going out on track on Friday of the first grand prix of the year.
And for the rest of the season, they are entitled to one upgrade which, once homologated, they can exchange with the first one for the rest of the season.
Yamaha has asked FIM technical officials for the device used to measure the maximum size of the fairings in order to be homologated, as it is currently too wide under the current rules.
The width of that fairing, which includes the front wings, is determined by a metal device on which the bike must be placed, without being able to touch the walls of the fairing in the slightest, as can be seen in the below image.
In 2019, Suzuki arrived at the first grand prix of the season with a fairing that didn't meet the required measurements, so all the aerodynamic work was exposed.
It finally had to trim the fairing the old-fashioned way, with a saw and a file, to get it to the allowed size.
"Right now, our two biggest concerns are the time attack and choosing the fairing," Yamaha sporting director Massimo Meregalli admitted to Motorsport.com on Friday.
"We have two fairings and we have to choose which one to go with," he added, although it has now emerged that they must also adjust the original design as it has become too wide.
This setback with its fairing is only compounding what has so far been a difficult pre-season for Yamaha and its 2023 bike.
Fabio Quartararo went as far as to admit Yamaha "will not be ready" for the opening round of the season due to the problems he has been facing on the bike in the Portugal test - with the 2021 world champion highlighting the bike's inability to gain time on fresh rubber as being the key concern.
