Jack Miller: Why I can’t race the Yamaha V4 this season

Jack Miller has explained why he won’t be able to race-develop Yamaha’s new V4 prototype during the remaining rounds of the 2025 MotoGP season.

Test rider Augusto Fernandez is giving the new machine its race debut as a wild-card at this weekend’s San Marino Grand Prix at Misano.

“It's really, really, really exciting, especially for the future of the project," Miller said of Fernandez's V4 debut. "It's a really crucial weekend for us.

“Hopefully, Augusto can have a problem-free weekend. With a brand new project as always, a race weekend is so different to a test day.

“Everything's scrutinised, everything's on time, you've got to react quickly throughout the sessions.

“So I'm looking forward to watching how the weekend plays out, and I've got my fingers crossed for them.”

Miller is now confirmed as saying at Pramac Yamaha alongside new signing Toprak Razgatlioglu for 2026 - and has more V4 experience than any other Yamaha rider from past seasons at Honda, Ducati and KTM.

Sitting only 17th in the world championship, Miller also has little to lose by finishing this season on the V4 prototype, to help prepare it for 2026.

However, although Yamaha's D concession status allows freedom to change engine design, their riders are limited to two fairing updates per season.

And with a V4 engine narrower but longer than the Inline M1 engine, the new bike has its own bespoke fairing.

Asked if he'd like to race the V4 this year, Miller told MotoGP.com: “It's not possible. Not from lack of trying, but we've homologated two fairings already.

“Other pieces [gearbox ratios], just in terms of spec, it doesn't work. So, as much as I'd love to gain data on it, it's not possible.”

The same is true for the other full-time Yamaha riders.

Instead, Fernandez is set to give the V4 further wild-card appearances at Sepang and Valencia this season, including at Sepang and Valencia, while race riders will be on board at Monday's Misano test.