Jonathan Rea has admitted his uncertainty over whether it was possible to extract more performance from his ageing Kawasaki ZX-10RR package spurred his decision to seek pastures new with Yamaha for the 2024 WorldSBK season.

The Ulsterman defects to the Japanese manufacturer this season on a two-year deal that sees him fill the seat vacated by BMW-bound Toprak Razgatlioglu.

The move brings about an end to Rea’s historic nine-season tenure with Kawasaki, a record-breaking stint that yielded six WorldSBK titles and achieved a mammoth 104 race wins.

A surprising deal for the many who expected Rea to see out the remainder of his career with the Spanish-based Provec Racing-run factory Kawasaki squad, Rea has previously cited a desire to challenge himself in a new environment as a reason for jumping ship.

However, he also admits that he felt there wasn’t much more performance available to be extracted from the ageing Kawasaki ZX-10RR, remarking that the team was ‘coming into the wall’ now in terms of development.

“For sure, you think the team is getting the maximum from the ZX-10RR and I felt like I did on track as well,” he told Bikesportnews. 

“Of course, there are things that we could have done better, I think inside the box we could have worked better together.

“But the team were doing a fantastic job. It is the same team now from when I was winning championships, they know what they’re doing, but it seemed like we were coming into the wall and that we’d reached the ceiling of development.”

"We pushed for a long-time for improvements"

After winning its first WorldSBK title for 20 years with Tom Sykes in 2013, Kawasaki would go on to enjoy a lengthy period of dominance for the remainder of the decade, the Japanese firm winning six consecutive World Championships with Rea between 2015 and 2020.

However, KRT boss Guim Roda has previously stated that a policy of incremental evolution during that period played a significant role in ensuring Kawasaki’s sustained success.

As a result, even though Kawasaki launched a new generation ZX-10RR as recently as 2020, many components under the skin can trace their roots all the way back to 2011.

It therefore leaves KRT with only marginal gains for development at this time and with no new Kawasaki ZX-10RR to homologate on the horizon, Rea was wary of a continued decline in competitiveness versus Yamaha and Ducati.

“We were pushing for a long time for some improvements with developments because the reference right now is different. 

“But we enjoyed being the reference in Superbike for many years, but now it is different, which is both good and bad - good for WorldSBK, but it wasn’t for us.”

After ceding his WorldSBK throne to Razgatlioglu after a thrilling season-long tussle in 2021, Rea would conclude the 2022 and 2023 WorldSBK seasons in a distant third overall behind the Turk and double champion Alvaro Bautista.