Yamaha's V4 MotoGP prototype is making strides, but there's still room for improvement. Jack Miller, a key figure in the development process, is optimistic about its progress, particularly in enhancing rear grip. However, he acknowledges that the engine's raw performance lags behind, especially after its underwhelming showing at Misano. Miller, who has tested the bike twice, is confident that Yamaha can extract more power from the V4. Despite the early challenges, Yamaha remains committed to refining the V4, aiming to strike a balance between rear grip and the bike's exceptional front-end capabilities. The next test for the prototype will be at Sepang, with test rider Augusto Fernandez at the helm. While the factory hasn't confirmed the V4's future, Miller is set to join the 2026 Yamaha lineup alongside Fabio Quartararo, Alex Rins, and Toprak Razgatlioglu. Miller, a four-time MotoGP race winner, is looking forward to continuing his journey, aiming to find his way back to the front end of the grid.