Kawasaki Ninja ZX-4R 400 2025 — Specifications

Thirty years. That's how long it took before a manufacturer dared to put a four-cylinder sport engine back into a 400 cc package. Kawasaki rekindles a flame that ZXR 400 enthusiasts thought had died out, and the Ninja ZX-4R arrives with the ambition of shaking up a segment dominated by tame twins. The bet is bold. The result, on paper, is genuinely exciting.

Don't confuse this machine with the Ninja 400 and its parallel twin designed for the A2 license. The ZX-4R plays in a different league. Its 399 cc inline four-cylinder produces 77 hp at 14,500 rpm — nearly double what the RC 390, Yamaha R3, or even the standard Ninja 400 offer with their 40 to 45 hp. The 39.2 Nm of torque only comes on at 13,000 rpm, and the redline stretches beyond 15,000 rpm. This is clearly an engine that lives in the upper registers, hollow at low revs but fierce once the needle climbs. A character reminiscent of the Japanese sportbikes of the 90s, brought into the age of fuel injection and electronics. The bore/stroke ratio of 57 x 39.1 mm and the 12.3:1 compression ratio confirm its calling: this engine was built to scream.

On the chassis side, Kawasaki has laid the foundations of a genuine little track weapon. The tubular steel trellis frame houses a 37 mm fork and a monoshock, all adding up to 189 kg wet. That's restrained for a four-cylinder. The braking setup impresses with dual 290 mm discs up front, gripped by Nissin radial-mount four-piston calipers. The 120/70-17 and 160/60-17 tires are standard sizes for the class, compatible with a wide selection of sport rubber. The riding position, with its clip-on handlebars, leaves no doubt about the machine's track-focused purpose. Sunday morning leisure riders looking for a scenic cruise need not apply.

The onboard electronics bridge the three decades separating this ZX-4R from its ancestor. Traction control, four riding modes (Sport, Road, Rain, and a configurable Rider mode), and a 4.3-inch color TFT display with a dedicated track layout that highlights the tachometer above 10,000 rpm, the selected gear, and lap times. The SE versions add a quickshifter with auto-blipper and more advanced suspension, inspired by the ZX-10R. The 15-liter tank demands frequent fuel stops if you ride hard, but on track, nobody fills up between two twenty-minute sessions.

That leaves the question everyone asks: what does the Kawasaki Ninja ZX-4R 400 cost? The base version comes in at €8,899. That's Ninja 650 money, except the character here is nothing alike. You trade the touring comfort of a smooth twin for the fury of a four-cylinder that only comes alive in the upper rev range. Against the Yamaha R7 and Aprilia RS 660, the ZX-4R counters with less displacement but a far more extreme personality. It's aimed at riders who prefer an engine you wring out rather than torque on tap from corner exit. With 192 hp per liter, this little Kawasaki boasts a power density that commands respect. Not a beginner's machine, not a toy either: a genuine riding tool for those who want to improve on track without burning through tires and fuel, while rediscovering the raw thrill of an inline four that revs to the moon like a formula car.