Inside Impression: Kawasaki Ninja ZX-4RR

Case in point: Kawasaki’s introduction of the Ninja ZX-4RR. Now Kawasaki, and its competitors, have all been producing smaller displacement sport bikes for years, but when it comes to sub-600 cc engines, single- and twin-cylinder layouts have been the mainstays for the last several years. With the introduction of the ZX-4RR, powered by a liquid-cooled inline four-cylinder 399 cc engine, it quickly became a major topic of discussion throughout the industry elevating this new model to must-ride status.

A review of the initial specifications that accompanied the ZX-4RR’s introduction confirmed that it had much more in common with the Ninja ZX-6R than the Ninja 400 that many naturally equated it to. Dual disc front brakes, traction control, selectable power modes, an up/down quick shifter and slipper / assist clutch with auto blip combined with sport bike ergonomics and adjustable suspension had track day enthusiasts everywhere jostling for position in the quickly forming lineups at their local dealer.

A call from Canadian Kawasaki Motors letting me know that a ZX-4RR demo had made its way to the western side of the country coinciding with a scheduled track day at the Rocky Mountain Motorsports road course north of Calgary set the stage for a test session worthy of the brand’s newest Supersport model. Yes, it meant a 14-hour roundtrip to BC to pick the bike up as well as a return visit the following week, but it turned out to be more than worth it.

With the ZX-4RR safely off the truck and in the garage at home – no, I wasn’t prepared to ride a 400 cc sport bike all the way from BC – the first order of business was to get some seat time in before heading to the track. Fortunately, living 20 kilometres away from the foothills of the Rocky Mountains means that world class twisties reside literally on my doorstep.

Initial impressions of a motorcycle naturally start with overall looks and in the case of the Ninja ZX-4RR, it is simply stunning in its green and black Kawasaki Racing Team paint scheme and added touches such as the green pinstriping around the edge of the 17-inch wheels (120/70 front and 160/60 rear) add to the overall look. Fit and finish are top-shelf and comparable with any of the models in the company’s lineup.

While every measurement of the ZX-4RR is smaller than the company’s flagship middleweight Supersport ZX-6R, the ergonomics will feel very familiar although slightly less aggressive, with the clip-on bars being slightly raised and rear-set footpegs a little forward and lower.

Of course, the real show starts when you turn the key and thumb the start button, bringing the engine to life and allowing you to twist the throttle for the first time and experience the tight succinct growl that emanates from the four-cylinder powerplant through the stock exhaust system. It is pretty much guaranteed that a good number of these bikes are going to end up on the track with full aftermarket exhaust systems and if it sounds this good with the stock system, one can only dream about how good it will sound when it is freed up.

Before heading out, a quick run through of the ride modes on the full-colour 4.3-inch TFT screen using the toggle switch located by the left-hand grip identified that in addition to the standard-equipped Sport, Road and Rain modes, the ZX-4RR also includes an additional custom mode which allows the rider to select power deliver as well as the level of intervention from the traction control system.

Working through city traffic in the lower RPM ranges, I must admit to being a little underwhelmed. A lot of commentary has been dedicated to the fact that the ZX-4RR on sale in Canada has been detuned to adhere to applicable noise regulation. Kawasaki does not provide horsepower or torque specifications, but initial impressions confirm it is well below the 75 horsepower and nearly 28 ft-lb of torque the brand advertises in other parts of the world.

Outside of the city on a conveniently empty stretch of winding asphalt, the opportunity to wind the engine out highlighted that the powerband starts to build around 7,000 rpm and then really comes to life when the tachometer hits 10,000. The only downfall is that while the engine is ready to scream all the way up to its 15,000 rpm redline, the power delivery flattens out around 12,000.

The obvious step for anyone in search of the full output would be a quick flash of the ECU, but even with the reduced power output the ZX-4RR was a blast to ride and left me anxiously anticipating our scheduled date on the racetrack.

At 3.6 kilometres in length with 18 corners, the Rocky Mountain Motorsports circuit is considered by many to be among the most technically challenging courses in North America. Complete with fast sweepers, tight decreasing-radius corners, dramatic elevation changes, hard braking zones and wide-open straightaways, this track and the Ninja ZX-4RR were destined to meet.

Arriving at the track, the amount of attention this bike got before it was even off the truck, reaffirmed that this is one of the most anticipated models of 2023. While my focus for the day was testing the ZX-4RR, I was also there working as a control rider for the local track day company, which would provide the perfect opportunity to experience the motorcycle at various paces as I circulated through each of the groups.

While the ZX-4RR has quickly become a coveted prize amongst some very experienced track day riders and racers, spending time riding at the pace of the Novice group highlighted that the bike can still be the perfect entry point to life on two wheels. Even at lower rpm the engine remains smooth and with the ride mode set to Road or Rain the throttle response is manageable and forgiving of unintended twists of the wrist. As an added benefit for new or returning riders, the 800 mm (31.5 in) seat height provides a more approachable reach to the ground than other sport bikes. The only potential challenge for inexperienced riders may be the bike’s stopping power, as the amount of initial bite from the dual front 290 mm discs is surprisingly aggressive and could definitely catch you off guard if you panic and grab a handful of brake.

While the ZX-4RR’s engine grabbed headlines when it was introduced, taking advantage of a couple of Intermediate sessions to get used to the bike at speed provided a new appreciation for the overall package that Kawasaki has put together. Drawing upon key developments that have worked their way down from the company’s World Superbike program and through their flagship models, the ZX-4RR handles with precision, responding immediately to rider inputs and feeling solid, even at full lean angle. As an aside, before channelling your inner Jonathan Rea, you will want to remove the rather large feeler gauges attached to the bottom of the footpegs.

After a few sessions, the back of my mind could not ignore the bike screaming at me that it had a lot more to offer, so after a quick double-check of the pressures in the standard-equipped Dunlop Sportmax tires, I jumped into the queue and headed out on the track with the Expert group. In fairness, there is no reasonable expectation that a 400 cc bike, no matter how well built it is, was going to be able to keep up with a group of expert riders and racers – many who were riding fully race-prepped litre bikes – but it was sure fun trying.

Despite some initial guilt of literally wringing the neck of this bike and rarely allowing the tachometer to read anything below 10,000 rpm, the combination of the screaming four-cylinder engine residing at the heart of this well thought out and put together motorcycle was simply addictive as the laps ticked by.

Adding to the simple joy of turning laps on the ZX-4RR is the inclusion of Kawasaki’s bi-directional quick shifter complete with auto blip. Keeping the engine within its tight powerband required a lot of shifting and this setup is truly outstanding and honestly the smoothest I have ever experienced. Paired with an assist and slipper clutch, as well as an ample 15,000 rpm redline, even the most aggressive downshifts are smooth and accelerating well past the point when the entire display becomes a flashing shift light doesn’t phase the bike at all.

It’s never a good idea to spend time looking at the speedometer when you are pushing towards the edge on the track, but admittedly temptation got the best of me, and the readout confirmed that speed was well up into the 180s. On a larger track this would likely eclipse the 200 km mark which is quite the accomplishment for a 400 cc machine. Even more impressive was how stable the ZX-4RR felt at speed despite its light 188 kg (414 lb) wet weight.

As a rider, tipping the scales at the 160 lb mark that the majority of Japanese and European manufacturers utilize as a benchmark for their stock suspension setups means that I rarely have to worry about adjustments. However, when I mentioned that the ZX-4RR was diving under braking, a couple of the experienced racers at the track suggested that this was more than just the aggressive brake setup I was attributing it to and suggested that we have a look at the suspension settings. While the rear suspension on the ZX-4RR is the same fully adjustable BFRC lite rear shock found on the ZX-10R, adjustments on the front fork are limited to spring preload. Adjusting the fork preload to its highest setting made all the difference and corrected the diving under braking; however, some riders, especially those who may want to race this model, will possibly look to upgrade the front suspension to include further adjustability.

There has been a lot of online commentary about the price of the Ninja ZX-4RR with some pointing out that the $11,199 MSRP on the Canadian Kawasaki website is only $2,000 less than the ZX-6R and others noting that you can acquire a Ninja 400 for only seven grand. Once you actually experience the ZX- 4RR, neither of these comments has any relevance. Firstly, the opportunity to do a few laps on a 2022 Ninja 400 KRT Edition in back-to-back sessions with the ZX-4RR absolutely confirmed that these are two totally different motorcycles and are in no way comparable other than the fact that they are made by the same manufacturer and have similar livery. With regards to the MSRP proximity to the ZX-6R, even before throwing a leg over the ZX-4RR, the impressive list of specifications firmly establishes this addition to the Ninja family as a member of the Supersport lineup as opposed to the Ninja 400 that many wrongly equate it to.

For those who are concerned about the price point, there is the option to save $700 and acquire the Ninja ZX-4R, but you will give up some features, most notably the up/down quick shifter and adjustable suspension, which seems like a lot to give up for just $700, especially when you consider the positive impacts these features have on the bike’s overall performance.

With the Ninja ZX-4RR Kawasaki has hit an absolute home run, creating a high-performance small-displacement Supersport bike capable of accommodating everything that the track, or the street can throw at it. It is impossible to know with any certainty if other manufacturers serving the North American market will follow suit, but until they do, Kawasaki has created a true unicorn that is both worthy of the attention it has garnered and a spot in your garage.

Kawasaki Ninja ZX4-RR

PROS:
+ 400 cc inline four
+ Top-shelf Supersport machine
CONS:
– Engine is detuned for Canada
– Limited front fork adjustment

MSRP: $11,199
Engine: Liquid-cooled inline four-cylinder
Displacement: 399 cc
Bore & Stroke: 57.0 x 39.1 mm
Compression Ratio: 12.3:1
Fuel Delivery: Fuel injected
Final Drive: Chain
Weight: 188 kg (414 lb), wet
Transmission: Six speed
Frame: High-tensile steel trellis
Wheelbase: 1,380 mm (54.3 in)
Seat Height: 800 mm (31.5 in)
Suspension (front):37 mm inverted fork with spring preload adjustment
Suspension (rear):Gas-charged shock with compression, rebound and spring preload adjustment
Tire (front): Dunlop Sportmax 120/70ZR17
Tire (rear): Dunlop Sportmax 160/60ZR17
Brakes (front): Dual 290 mm disc with radial-mountmonobloc 4-piston calipers
Brakes (rear): 220 mm disc with single-piston caliper
Fuel Capacity: 15 L