Bike Review | 2024 Kawasaki Ninja ZX-4RR Road & Track Test

With many bikes becoming sensible and conservative, it’s refreshing to have a brand release a bike that pushes against those trends. The Kawasaki Ninja ZX-4RR is a bike that isn’t LAMS approved, cheap or practical and doesn’t look like it’s from the ’70s.

We first rode the Kawasaki ZX-4RR at the Aussie launch in October 2023 at Morgan Park Raceway.

Here is why I reckon the Kawasaki Ninja ZX-4RR is a fantastic bike long overdue for Aussie shores. With so many bike brands tagging their street sports commuters as sportsbikes, which they are clearly not, we are starting to get a generation of younger riders that just don’t actually know what a real sportsbike is, let alone what a fast small capacity bike is like a Kawasaki KR-1S from the 1990s. We needed a full licence small bike to come along that has the frame and geometry of a sports motorcycle. This one has big bike electrics, highway comfort, modern styling with the old school fun included!

I grew up racing two-stroke 250s before moving to SuperSports and Superbikes, and I also had a bit of fun racing for Kawasaki Motors Australia on their Ninja Cup bike a decade ago, a Kawasaki Ninja 300. As fun as that Ninja Cup bike was, I can tell you that they are definitely not sportsbikes. Great bikes, sure, but the frame twists like fresh pasta once the lap times come down, particularly if grip is involved. The Ninja ZX-4RR is, despite a steel frame, a true sportsbike and thus the premium price tag.

Kris Hodgson on our BikeReview Project Ninja 400, which he bought with his wife as he was som happy with the bike.

The others are getting faster nowdays, for sure, but essentially they are commuter bikes with fairings, and they are based on bikes like the GPx250 that goes way back to the early 1990s… They are fantastic road bikes, and track day fun for sure. In fact, we love then so much we had a long termer. You can read all about the BikeReview Kawasaki Ninja 400 here… But lap time wise, they are 30-years behind and only now in the same area as 250s were in the early 1990s, say low 1:40s at SMSP…

The BikeReview Kawasaki Ninja 400 Long Termer

Kawasaki ZX-4RR

But four-stroke small capacity bikes can be fantastic. In the late 1990s I moved to Japan to have a crack at racing over there. It was then that I was introduced to some seriously trick multi-cylinder four-strokes that I had no idea existed… all brands had their 400 and they were true sportsbikes, doing similar lap times to the 250cc production two-strokes. They were big in the UK, also, and punted against the 250s. My favourite was the ZXR400R… Check out Fogarty and Whitham, RGV v NC30

ZX400M via ZXR4me.

ZX400M photo via Iconic Auctioneers.

1989 ZXR400

1995 ZXR400R.

The Ninja ZX-4RR comes in at $15,644 R/A ex Sydney, which is near on six grand more than the new Ninja 500, or five grand more than the Ninja 500 SE 40th Anniversary Edition. But it also has a whopping 30hp more power, but on the other hand it is only three grand less than the ZX-6R, which has 55hp more than the ZX-4RR! So, you have to ask yourself, where does this bike sit? Well, it sits in a tiny niche market of people who either grew up riding these, or like corner speed and revs big time…

On the current ZX-6R at SMSP.

The ZX-4RR at Morgan Park.

For us over 40s Aussies who remember the pre power-to-weight learner days when we could ride 60hp, 130kg two-strokes, the ZX-4RR will touch a soft spot as it did with me. I had no access to four-stroke 400s, as they were not imported here generally, I still reckon it is the next best thing available these days and therefore would buy one if I had the spare cash. For those who grew up in the UK, Japan or parts of Europe riding four-stroke four-cylinder 400s and 250s, you will be love struck.

The KRT Edition we tested looks like a shrunken ZX-6R or ZX-10R at first glance. A gorgeous little machine.

On The Road

I picked the Ninja ZX-4RR up from Kawasaki HQ just before a big storm was about to hit. There it was, immaculately prepared as per usual for KMA, and I was about to filthy it up. But I was happy, as it kind of reminded my of my early riding years on my 250s, when I had no other transport and rode a sportsbike rain hail or shine. So the Ninja and I were about to bond in the rain… I was excited.

Even in the rain on the Old Road, I was having fun, and did an extra lap. That says a lot for the bike.

Heading off, the first surprise was the bottom end to mid range pull. I expected to need 10,000rpm-plus dialled to get going but Kawasaki have somehow worked magic into the 4RR as it pulls cleanly from 3000rpm and can be short shifted in light traffic between the 3500 and 6000rpm mark, keeping up with the flow and remaining silky smooth. It is really good in traffic, with a super light clutch and a narrow overall width, making it a breeze to commute on. It doesn’t have punch, but it makes progress.

Taking us back to the 1990s and true small capacity sportsbikes is something Kawasaki should be praised for.

But out of town and into the twisties is where the fun started. I did a lap of the Old Road in the rain, and it was still fun. The soft suspension, linear power delivery, gentle brake bite and communicative front-end, matched to the brilliant Dunlop SportSmart tyres, meant it was one of those fun rain runs. But as a dry line began to appear, the fun really began and I started to appreciate the ZX-4RR more and more. It’s small, light, flickable and racy. It’s like a KR-1S with a bit of weight making it more planted!

The brakes are good, the Dunlops are fantastic.

Radial-mount calipers up the front.

The rear brake is good, just enough bite and feel.

Conventional master-cylinder.

As the pace on the road increased with the dry tarmac, the suspension did begin to show its softness. I stopped and adjusted it, and discovered that the fork preload was wound all the way out to max soft. I soon sorted that out, added a hell of a lot of preload and this is when I also realised there was no other fork adjustment, which is bizarre. Out the back, I firmed up the lot on the shock. But even after those changes, the forks remain too soft. The shock is OK, the forks are under-sprung by a long shot.

Adding preload to the forks.

Adding preload to the shock.

Adding comp and rebound to the shock.

The shock offers easy access to adjustment.

Suspension sorted as well as it can be given the soft springs, I continued to lap the Old Road and having a blast. As long as I wasn’t too sudden and hard on the brakes, and kept the braking progressive, it was possible to ride around the soft forks and keep the ZX-4RR balanced. The plus-side is the plushness soaked up all the bumps and added feel into turns. And the great geometry compensated for the fork set-up. A great chassis through the local hills but somewhat held back.

Four-into-one exhaust, large radiator.

Slipper clutch, cable actuation.

KRT wheel stripes, Dunlop SportSmart tyres.

Dunlop SportSmart rear tyre.

Engine-wise, on the road, the little inline four is fantastic. It has a really engaging and addictive intake and exhaust growl that turns into a howl as the tacho reaches the 16,000rpm redline. As mentioned, it’ll get you along from 3k onwards, but where the fun lies is way up the range. From a whopping 10,000rpm to around 15,500rpm the Kawasaki Ninja ZX-4RR absolutely hauls… and keeping up with the tacho is made easy with the quick-shifter, although I did note that the quick-shifter has a sloppy feel, a long throw and sometimes misses a gear as a result.

The quickshifter had a rubbery, sloppy feel and a big throw.

The dash is simple and fantastic. Check out that redline! This is in day mode.

4.3in TFT in night mode.

Left hand controls, dash menu is with left thumb.

The Ride Modes come in handy but with such a linear power delivery and a modest 75hp, they are not really needed. I left Kawasaki in Rain mode, in the rain, but soon switched to Road, then Sport where I spent most of the 1000km test. When I went to the track, I used Rider Mode to give full power and minimal KTRC. But generally, on the street, Road or Sport are fine. The throttle mapping is so silky smooth and the power delivery so progressive, traction control would only be for emergency slides from sudden changes in surface grip, rather than to fight wheelspin or tyre wear.

“The ZX-4RR is ultra flickable, more than just a shrunken ZX-6R. It goes where you look and has true racer feel.” Pic: Bernie Hatton

On Track

I headed up to a tight and twisty local supermotard/go kart track to test the Ninja ZX-4RR and it was great fun. The light weight of the overall package, combined with the rev happy nature on the inline four, really made for an engaging ride. But tall road-bias final gearing and those super soft front forks, combined with what I discovered was a slow leaking front tyre, sure made it hard work on my upper body on the tight and challenging layout. But the grin factor was as off the dial as the 16,000rpm limit!

Tight and twisty tracks are the domain of the ZX-4RR.

High corner speeds and lean angles are easily achievable.

Acceleration off turns is about timing the rpm right.

Soft forks held the bike back on track and road.

Chassis-wise excluding the soft forks, the ZX-4RR is ultra flickable, more than just a shrunken ZX-6R or ZX-10R. It goes where you look and has true racer feel. The brakes are excellent, but I would prefer 300mm to the 290mm rotors for a bit more bite. The rider triangle ergonomics suit the track, not to say it isn’t also comfy on the motorway, as it is quite good… The engine is eager and tractable and overall it’s a blast and has a very impressive top-end, too. For more on the track test, check out Zane’s test at Morgan Park Raceway, where he could wind it right out.

Special Thanks to the NSW Supermoto Riders Club for the track time.

Conclusion

After a few weeks road riding the Ninja ZX-4RR and a track morning, the bike proved to be exactly what I thought it was the first time I saw the specifications in the Kawasaki press release – the Ninja ZX-4RR is an incredibly engaging, capable, refined fountain of youth. It’s a niche bike for a limited market but we need variety and we desperately need more real sportsbikes. This is exactly why I think it’s a fantastic bike, long overdue for our shores, and I recommend you snap one up before Kawasaki change their minds! By the way, make mine a Kawasaki 40th Anniversary Edition thanks!

The Kawasaki Ninja ZX-4RR 40th Anniversary Edition is our pick, with its 1990s Kawasaki Racing colours…

 “The Ninja ZX-4RR is an incredibly engaging, capable, refined fountain of youth”…

Zane’s Ninja ZX-4R Test
After a few sessions on the RR, I decide to try the single R for a few laps. The single R was fitted with the standard Dunlop Sportmax hoops, so I ride with a little more caution than I was with the RR. It turns out there’s no need, as the R provides just as much instant confidence to put the hammer down.

“After a few sessions on the RR, I decide to try the single R for a few laps. The single R was fitted with the standard Dunlop Sportmax hoops, so I ride with a little more caution than I was with the RR.”

I almost feel like the stiff nature of the non-adjustable SFF-BP forks and the simple shock suit my weight and riding style better than what the RR was set to. There’s less dive in the front, and the rear feels planted despite not having the same grip level with the road bias tyres.

“The road bias tyres make the R even twitchier and easier to change direction than the RR with the TTs. Off the showroom floor, this thing is ready to boogie through your local twisties.”

The road tyres make the R even twitchier and easier to change direction on than the RR on the TTs. Off the showroom floor, this thing is ready to boogie through your local twisties. The lack of a quick-shifter on the R is enough to make me want to throw myself back on the RR though. You can’t extract that same level of smoothness out of this engine without having those lightning-fast gear shifts.

The single R features all the same styling as the RR but comes in this sleek black colour scheme…

Zane’s ZX-4RR vs ZX-4R Opinion
I would opt for the Ninja ZX-4RR every time. You get an excellent level of equipment straight out of the factory for a price of $13,194 + ORC, but the single R (no price currently on KMA website) is undoubtedly worth considering if you can’t get your hands on a RR or just don’t like the green. There is also a KRT edition for $13,94 + ORC. If it comes down to it, you can always add the quick-shifter as an accessory and possibly even buy that fully-adjustable shock later.

“I would opt for the ZX-4RR every time. You get an excellent level of equipment straight out of the factory for a price of $13,194(+orc), but the single R is undoubtedly worth considering at $11,794 (+orc) if you can’t get your hands on a RR.”

Kawasaki Australia have said they’ve only bringing in 80 of the RR and R combined for their first MY. You’re going to want to hit your local dealership before people realise they don’t need 200hp to have fun on Australian roads. But be quick! 

Kawasaki Australia have said they’ve only bringing in 80 of the RR and R combined for their first MY. You’re going to want to hit your local dealership before people realise they don’t need 200hp to have fun on Australian roads.

This has been one of the only bikes in 2023 that I have seriously considered buying. The engine is so much fun and easy to ride, I see potential in the suspension being set up to my liking, and it’s a future classic. Kawasaki has done a fantastic job providing a base for a pocket rocket, and I’m praying that we will get to see an Australian race series for these. I’m also hoping that the other major manufacturers will soon follow this path of bringing back high-revving, low-capacity sportsbike for the general public.

For our full Tech Talk Details on the Kawasaki Ninja ZX-4RR, head here…