Writing this text may indeed reveal my age, but it's also a testament to fond memories of the golden era of Japan's 400cc four-cylinder sports bikes in the mid-1990s. Here's a condensed version:
"In 1994, at the age of 18, I had the privilege of experiencing the latter part of Japan's 400cc four-cylinder sports bike golden era. It was an incredible time for young bikers. From the Yamaha FZR400RR to the HRC-spec Honda NC30, these compact machines not only mirrored World Superbikes on TV but were also regarded as true sports bikes in their own right. Riding a 400cc, relatively low-powered bike wasn't a source of humiliation; it earned respect.
Many of us UK teenagers, myself included, clung to our beloved two-strokes like the Suzuki RGV250 and Kawasaki KR-1S. This split us into two tribes. The majority of my friends opted for the four-stroke route, and the Kawasaki ZXR400 was possibly the most popular among them. It was a pocket rocket, brimming with attitude, and provided a maniacal riding experience that, even today, leaves many of us craving one."
Enter the 2024 Kawasaki Ninja ZX-4RR
The 2024 Kawasaki Ninja ZX-4RR tested in Spain is the top-spec RR version and is full power, which equates to a quoted power of 57kw/76.4hp at 14,5000rpm, and 58.7kw/79.1hp with ram-air at the same dizzy 14,500rpm. Peak torque of 39Nm/28.8ftlb, is predictably high in the rev range at 13,000rpm. These are impressive figures for a small-capacity Euro5 bike, and far superior to the old ZXR400, which even in a highly tuned and unreliable race spec would only make 75 to 80hp.
Please note that in the USA, it appears that the ZX-4RR is restricted to 42kW (56.3hp), while in Australia the power is pegged at 55kW (73.8hp). Revs appear to be the limiting factor, with Aussie models peaking at 14,500rpm. Canadian versions rev no higher than 11,500rpm.
This was a track-only test, conducted in the perfect environment of the tight and twisty Calafat racetrack, about one hour away from Barcelona in Spain. The 3.25km track had a 600m straight, was blessed with perfect conditions, and hosted seven long sessions that allowed us to really chase every single rev. All 16,000 of them.
With less than 30 pound feet of torque and peak power up at 14,500rpm, you need to keep the ZX-4RR on full volume. Thankfully, there is a super-smooth up-and-down quick-shifter as standard on the RR model that allows you to keep the rev counter north of 10,000rpm.
The 399cc, 16-valve motor loves to rev, and is more than happy to be abused, even allowing an over-rev between turns. When you occasionally hit the rev limiter at around 16,000rpm, it's soft and not too intrusive. Ideally, you don’t want to rev any higher than 15,000, that's just beyond peak power, but to try instead to maintain the lovely sweet spot between 10,000rpm and 15,000rpm.
This is not a slow bike by any standards. My ZX was clocking 120mph at the end of the 600m straight with rpm in hand and another gear to go. I’d estimate that in the right conditions, it should be good for 130mph-ish.
It’s so rewarding and enjoyable to trash on track. You can be reasonably aggressive with the throttle, winding it happily to the stop. You don’t have to tickle the power in the lower gears like you would on a superbike. Instead, stay tucked and keep those revs coming. Should you get a little too carried away, there is three-stage traction control, which is of the conventional type that uses wheel speed sensors and not lean sensitive.
We had an official accessory road-legal Akrapovic muffler fitted (£914 in the UK; unlisted in the US), which added even more desirability to the package, in addition to a pleasing rasp. I thoroughly loved riding the ZX-4RR on track, in part because after seven sessions in blistering temperatures, I wasn’t even slightly fatigued.
That's because the ZX-4RR is so easy to hustle; it’s not intimidating, you have time to pick the right line, spot your braking markers, and get that corner just-so. You’re not rushing up to corners, scaring yourself on the stoppers and then having to muscle it to the apex. It flows naturally, carries its speed and then unleashes a riot of revs and wailing exhaust that make you feel like you are on lap-record pace!
As this was a track-only test, I rarely allowed the revs to drop below 9000rpm, but on the cool-down lap I did play around with the mid-range. It’s not completely gutless, and you can make progress, but I expect that making a fast getaway from the lights is going to require several handfuls of revs. But that’s what makes it fun, isn’t it? With the TC off, wheelies are just about possible in first gear, but you have to be brutal.
As mentioned, we enjoyed perfect conditions in Spain and, interestingly, Kawasaki decided to fit Pirelli Diablo Rosso III rubber rather than the Dunlop GPR300 that will come as standard in the UK and US markets. I was also a little unsure what to expect from the ZX-4RR itself as the original 1990s ZXR400 was a fully adjustable mini superbike, with impressive handling and a lightweight alloy frame – not steel like the new model.
The first two learning sessions were easy and revealed an impressive base package. Manufacturers often scrimp on suspension spec to reduce costs on lower capacity bikes, but this doesn’t appear to be so with Kawasaki. Whilst getting used to the track, the ease-of-use of the ZX-4RR shone. I felt instantly at home and found a decent pace straight from the off.
That all-important front-end feeling was excellent, of a similar quality to the benchmark ZX-6R and ZX-10R. Kawasaki had tweaked the suspension for this track test, adding two turns of preload on the front and, while running standard preload on the rear (horizontal, ZX-10 style) shock, but with 1.5 turns of compression and rebound to the rear.
This was obviously done for the high temperatures and grippy rubber fitted. I later added another 0.5 turns of compression and rebound damping on the rear just to cater for my weight. The changes were instantly noticeable, again a good sign that Kawasaki hadn’t opted for budget suspension, despite the absence of damping adjustment on the front forks.
With that confidence-boosting feel from the front end, the ZX-4RR encourages you to let go of the brakes and run in hot to the apex. The steering is light and direct and the whole machine is joyfully easy to throw around.
Despite being light and small, it tracks accurately without any of the instability you might expect from a lightweight, and there’s enough room to hang off the inside, knee slider truly buried in the Spanish race track. Even when the pegs (with hero blobs removed) start to tickle the track, you can feel the ZX-4RR giving you feedback.
Towards the end of the session, the Pirelli rubber was struggling with the combination of high temperatures and a heavy-ish rider pushing for lap times. But even when the Kawa gave the odd slide, it was progressive and non-threatening. By the way, I’d expect the race version on race rubber to deliver some surprising lap times.
On the road and with standard settings, I expect the suspension to be on the soft side, catering for new and inexperienced riders, and I don’t think the Dunlops will perform as well as the Pirellis on track.
The brakes are forgiving and strong enough for some track fun, but not too sharp for inexperienced riders. The brake (and clutch) lever is span adjustable. Even at a decent track pace, the stoppers didn’t feel like they were on the limit and showed no indication of fade.
The ABS is conventional and not lean sensitive. Once I started pushing for a fast lap (sorry, the race dash made me do it), it was a little intrusive, but this is to be expected on an entry level sports bike. You have to be pushing for a fast lap to feel the ABS working near the limit, and most riders on track never felt any intervention. I also expect that you won’t feel it on the road.
This was a track-only test, therefore it’s hard to judge comfort and long-distance use. However, despite its compact proportions, the ZX-4RR is reasonably roomy. I’m nearly 5'7" and I didn’t find it too cramped. There also weren't many complaints from the taller riders on the test. For me, it's more comparable to a 600cc supersport, certainly larger and roomier than the ZXR400 from the 90s.
The view from the seat is neat: Switchgear that, like most Kawasakis, is relatively simple, and a clear 4.3-inch TFT dash that has connectivity. There are four riding modes – Sport, Road, Rain, and Rider (manual) mode, which changes the power (full or low) and KTRC traction control (levels one to three and off).
There’s an additional Circuit Mode that changes the screen to give a large lap timer and rev counter, which is ideal for track day fun and somewhat addictive. Preload adjustment is on the right-hand 37mm Big Piston Fork.
Styling-wise, the ZX-4RR is very much a baby brother of the Ninja ZX-6R and ZX-10R, and could easily be mistaken for one of its bigger siblings. As much as I like the old ZXR400, I equally like the new ZX-4RR. Despite being a small capacity bike, it’s a machine you can be proud of.
Gallery: 2024 Kawasaki ZX-4RR First Ride
The new ZX-4RR seamlessly continues where the original left off, offering improvements in neatness, speed, safety, roominess, and ease of riding.
Kawasaki's decision to produce this unique bike in today's market, the sole sports 400 available, is a bold one, but I'm so happy they did. While the ZX-4RR might not achieve the same legendary status as the original, it's a blast to ride, with a love for revving, user-friendliness, and forgiveness that new sports bike riders will appreciate and love. Equally experienced riders, like myself, can fine-tune the suspension, hunker down behind the low screen, and enjoy some old-school fun.
I spent an entire day riding the ZX-4RR on the track, pushing it to the limit every lap, and using all its power. Remarkably, I didn't feel fatigued at the end. I can't recall having that experience with any other high-quality sports bike in recent memory. The small-capacity sports bike has made a comeback, and for that, we have Kawasaki to thank.
The 2024 Kawasaki Ninja ZX-4RR is available from Kawasaki dealerships in the US now. MSRP in the US starts at $9,899 for the base bike, $10,099 for the KRT Edition, or $10,299 for the newly-introduced 40th Anniversary Edition. Price and availability elsewhere in the world may vary by country.