Valencia MotoGP Test: Franco Morbidelli backs up Fabio Quartararo’s engine fears, Yamaha ‘will investigate’ After finding improved performance with Yamaha’s first specification of its 2023 engine at Misano, Fabio Quartararo was left shocked at seeing no performance gains in Tuesday’s Valencia MotoGP Test relative to the previous 2022 engine, something Franco Morbidelli has since backed him up on.