Forbidden fruit is always the sweetest and as such Kawasaki’s jewel-like ZX-25R – a 250cc four-cylinder sports bike that’s offered in some Asian markets but not in the West – seems all the more desirable.
Now Kawasaki are planning to launch an even more tempting machine in the form of a more powerful 400cc version retaining all the lightweight, high-revving appeal of the original.
While rumours of such a machine have swirled ever since the original ZX-25R was launched, sources in Japan now say that the bigger ZX-4R is all but certain to be launched soon.
What’s more, there’s hard evidence for the bike’s existence in the form of patents filed by Kawasaki themselves. A document first published by the Japanese patent office in 2019, clearly states that the design is “preferably applied to a vehicle having four- cylinder 400cc engine”.
As shown in this computer illustration of the upcoming ZX-4R, the new bike is expected to share the vast majority of its parts with the existing ZX-25R, including the tubular steel frame, banana swingarm and most of the bodywork.
The lower panels, already used on the ZX-25R, are at the heart of the patented cooling system, with internal ducts to feed air to the alternator on the left and clutch on the right.
Sources say the new ZX-4R will sport a new nose and headlights, mimicking the look of the latest ZX-10R superbike, along with a ZXR750-inspired paint scheme.
Since the ZX-25R manages a claimed 50.3bhp at 15,500rpm with the help of ram-air, the ZX-4R could be capable of as much as 80bhp. Perhaps more importantly, its torque is certain to rise from the 250’s limp 16.9lb.ft (which doesn’t arrive until 14,500rpm) to about 24lb.ft.
Like the ZX-25R, the ZX-4R’s main target market is likely to be Asia, but its larger capacity and increased performance might be just enough to persuade the firm to jump through the type-approval hoops to offer it Western markets
