Kawasaki ZX-4RR: The Return of the 400cc Supersport

The late '80s and early '90s were a golden era for 400cc four-cylinder sports bikes. Models like Honda's NC30 and CBR400RR, Kawasaki's ZXR400, Suzuki's GSX-R400, and Yamaha's FZR400R were engineering marvels of their time. These machines were essentially scaled-down superbikes, offering a perfect balance of performance and handling. They were lightweight, agile, and fast enough to leave a lasting impression on anyone who rode them.

Fast forward to today, Kawasaki has revived this legendary class with the ZX-4RR.

A Modern Take on a Classic Class

With the ZX-4RR, Kawasaki has brought back the spirit of those iconic 400cc bikes, but with modern tech and performance. Sporting a 399cc inline-four engine, the ZX-4RR produces a healthy 75hp in its European spec. That output blows away its 1990s predecessors, all while being equipped with fuel injection and Euro-5 compliance, making it both powerful and easy to ride in everyday conditions. From screaming through back roads to smoothly cruising through urban traffic, this bike does it all without a hitch.

In terms of pricing, the ZX-4RR sits at £8,699, which is around £2,000 more than Kawasaki’s Ninja 400, a twin-cylinder model. Despite the price difference, the ZX-4RR nearly doubles the power output of the Ninja 400 and even outperforms the Ninja 650 by 10 horsepower. This positions it nicely in Kawasaki’s lineup, offering more bang for the buck without stepping into ZX-6R territory.

Engine: Built to Rev and Roar

Derived from the smaller ZX-25R, the ZX-4RR’s 399cc engine gets its extra displacement from an increased bore and stroke. This gives it a power output of 57kW (76.4hp), which jumps to 59kW (79.1hp) thanks to a ram-air system at higher speeds. Riders in the U.S. and Australia, however, will see slightly reduced power due to market-specific restrictions.

Four riding modes—Sport, Road, Rain, and a customizable Rider mode—offer flexibility, adjusting power delivery and traction control settings to match riding conditions. Additionally, the ZX-4RR comes with an up-and-down quick shifter as standard, which is a blessing when you’re working the engine in its upper rev range.

With peak power arriving at a lofty 14,500rpm and torque peaking at 13,000rpm, this bike thrives when pushed hard. Its quick-revving nature and wide powerband, ranging from 8,000rpm to the redline at 16,000rpm, make it a blast to ride. However, the bike requires a skilled touch when launching from a standstill to avoid too much noise without enough forward momentum.

Performance: A Supersport in Disguise

On paper, the ZX-4RR might not seem overwhelmingly fast, but it’s all relative. Coming from a 125cc, this bike will feel like a rocket. If you’re stepping down from a larger bike, it may take a bit of adjustment. The real surprise comes when you glance at the speedometer and realize just how quickly you're moving.

The ZX-4RR shares some similarities with 1990s two-stroke 250cc bikes in its power delivery. The engine builds power progressively, without the sudden surge you might expect from other sports bikes. This makes it easier to control and less intimidating, especially for riders looking to sharpen their skills on a track or twisty roads.

Despite its aggressive nature, the ZX-4RR is a versatile machine. It’s surprisingly easy to ride in traffic, and the quick shifter is a real boon for city commuting. The trellis frame, inspired by the ZX-25R, combined with the compact wheelbase, makes it nimble without sacrificing stability. Showa’s suspension, including SFF-BP forks and BFRC-lite rear shock, adds to the bike's ability to handle both spirited riding and everyday use with ease.

Comfort and Practicality

For a sports bike, the ZX-4RR offers a commendable level of comfort. Its riding position is sporty yet roomy, making it suitable for both daily riding and weekend canyon carving. Despite the low-slung bars and high rearsets, it’s more comfortable than larger sportbikes like the Yamaha R7 or even the Honda Fireblade.

Fuel economy, however, is where you might notice the compromise. Pushing the bike to its limits will result in around 45mpg, which isn’t stellar compared to some of its competitors. But with a full tank of 15 liters, you can expect around 165 miles of range in mixed riding conditions.

Handling and Braking

The ZX-4RR feels right at home on twisty roads and is forgiving enough for newer riders. Its 160-section rear tire offers excellent grip, and the handling is confidence-inspiring even on less-than-ideal road surfaces. Kawasaki has done a stellar job of balancing the bike’s agility with stability, and the suspension is more than capable of absorbing bumps without unsettling the chassis.

Braking is sharp, and the bike’s 188kg weight with a full tank makes it easy to manage. Whether you’re filtering through traffic or carving up a backroad, the ZX-4RR feels precise and responsive.

Final Thoughts: A Bold Move by Kawasaki

Kawasaki took a bold step by reintroducing the 400cc four-cylinder category with the ZX-4RR. It’s a rare breed in today’s market, but it brings a level of excitement that’s hard to match in this segment. For both new riders and those looking to rekindle the joy of a high-revving, lightweight sportbike, the ZX-4RR delivers in spades.

It may not be the fastest bike out there, but it offers a unique blend of performance, handling, and character that’s hard to find elsewhere. Kawasaki has crafted a bike that’s just as fun on the track as it is on the daily commute, making the ZX-4RR a worthy successor to the iconic 400cc sportbikes of the past.

Are you ready to relive the glory days of the 400cc supersport class? The Kawasaki ZX-4RR might just be your ticket back in time.