Kawasaki Ninja ZX-4RR & ZX-4R Review
Words by Wayne Vickers, Images by MotoThing
Can you believe that it’s been almost 25 years since the glory days of the Japanese 400 supersports being in full flight? Seems crazy that there’s been that gap for so long. But it’s another case of everything old being new again; and we the punters are better for it.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC00335-1024x683.jpg)
Team Green is the first Japanese manufacturer to have a ‘proper go’ in the segment again – and we were lucky enough to get a chance to sample the two new variants up at Queensland’s brilliant Morgan Park circuit. Putting the little screamer through its paces on the flowy 2.1 km circuit highlighted just how good a job they’ve done with it.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC00336-1024x683.jpg)
Someone referred to it as a 250 supersport on steroids on the day and I think that seems pretty apt. My first road bike was actually a 1991 Honda CBR250RR that I ended up putting over 100 thousand kays on. I had plenty of fun on that bike and it taught me how to ride without relying on power. This feels like a grown up version of that, albeit having hit the gym a little.
![Kawasaki ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2024-Kawasaki-Ninja-ZX-4RR-Wayne-15-1024x577.jpg)
Let’s look at some key elements first:
- It’s running a healthy 399 cc inline four belting out 77 hp and 37 Nm thanks to a little ram air assistance
- It’ll redline around the 15,500 mark (and sounded pretty ace along the pit wall)
- It’s up a bit on the twin cylinder Ninja 400 when it comes to weight, tipping the scales at 188 kg
- Six-speed box comes with a slip-assist clutch; and quick-shifter on the RR
- Ride modes including a customisable Rider mode allowing adjustability of power and traction control
- The Quickshifter and up-spec fully adjustable suspension are the only differences on the RR
Now. The number that jumped out to me first was the 77 hp one. That’s a pretty solid figure from a 400 by any measure. Thinking back to the old days when the mid 60 horse mark was the ballpark for these little puppies. So let’s say it’s about 20 per cent up on the old crop.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2024-Kawasaki-Ninja-ZX-4RR-Wayne-8-1024x577.jpg)
And the second number that popped out was the 188 kg mark. Which is about 15 per cent up as well. And while I myself am one to grumble at bikes getting heavier, a lot of that is mandated. Modern bikes have to have ABS, EFI, and all the electronics and sensors required for those systems. They all add cables and wires and much more weight more than you might think.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC00412-1024x683.jpg)
We also get beefier (and much better) suspension than older generations. And then of course there’s a great chunk of weight in complying with modern emission requirements. So it is inevitable – and we need to compare apples with pears when it comes to weight.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC00386-1024x683.jpg)
That said, power to weight is still up. And if you think about what could be saved by throwing on a full system for instance… it’d be more of a saving than days of old.
Having said all of that, I was shocked when I read that 188 kg figure. Rotating mass has a lot to answer for as it in no way feels like a near 190 kg bike once you’re on board.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2024-Kawasaki-Ninja-ZX-4RR-Wayne-11-1024x577.jpg)
In fact, the first impressions when I threw the leg over went as follows:
- Oh this is roomier than I expected.
- Comfortable too actually…
- Man that first gear is short.
- This bike turns like a dream.
Once I had a couple of laps under the belt and the bike and body had warmed up, I started to wick it up and have some fun. Even after only that first session it was apparent that this little green package has one major strength.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2024-Kawasaki-Ninja-ZX-4RR-Wayne-13-1024x576.jpg)
It wasn’t the fact that the engine has a power curve flatter than Lake Gardiner. Nor the fact that you can keep it above 10 thousand revs and it dishes out smooth fuss free, utterly usable power.
Nor was it the fact that the tip in and handling are so confidence inspiring that you end up pretty quickly dragging knees and scraping pegs on a track you’ve only been on for 20 minutes, on a bike you don’t know.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC00374-1024x683.jpg)
Or even that fact that the quick-shifter on the RR and slipper clutch let you sail into corners with confidence knowing nothing is going to get out of shape.
Nope. Its major strength is no single one of those things.
It’s the fact that it all comes together so well and results in a bike that is utterly confidence inspiring and dead easy to ride. Usable is the word. It’s just so damn usable. You’re not overawed or intimidated in any way – you’re left able to simply focus on riding and having fun. Learning the track. Picking your reference points. Keeping it smooth. Nailing the apex and getting that drive down the next straight.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2024-Kawasaki-Ninja-ZX-4RR-Wayne-1-1024x638.jpg)
I came in after the first session a sweaty mess. Not because it was stressful in any way, but because I was already able to have a decent crack within one session. On a new bike. On a new track. Tyres well balled up and plenty of smiles. No moments. Everything kept super tidy. Ripper. Oh… and that sweat may have also been influenced by the fact that I’m still an unfit pile of pies.
Here’s a lap from the end of that first session care of the Forcite lid. Now the Forcite does its best to muffle external noise, but you can still hear that little in-line four hammer.
For the second session I jumped on the single R which differs only in that it has no quick-shifter and runs lower spec’ suspension that is only adjustable in the rear for pre-load.
![Kawasaki Ninja ZX-4R](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC04733-1024x683.jpg)
I gotta tell ya, while I had to squeeze the brakes ever so slightly earlier and smoother than the RR (which would have been mostly solved by adding a little more rear preload), I was only marginally slower on the R.
In fact the only area where it was really noticeable was into turn one hard on the brakes where it gets a little choppy at Morgan Park. The combination of not-quite-as-good suspension and not having a quick-shifter meant I had to be more on my A-game to keep it smooth and get it right.
![Kawasaki Ninja ZX-4R](https://www.mcnews.com.au/wp-content/uploads/2023/10/2024-Kawasaki-Ninja-ZX-4RR-Wayne-6-1024x619.jpg)
Whereas on the RR I could bang it down two gears, tip it into turn one on the gas and then hold it in second until after turn two. I found it easier on the R to drop down just one gear before the first corner, then another after turn one. Either way, still loads of fun.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC00321-1024x683.jpg)
But it did highlight just how composed the RR was when I got back on it for the third session and pushed again. Super stable and fuss free. Turn one was sooo much smoother.
![Kawasaki Ninja ZX-4R](https://www.mcnews.com.au/wp-content/uploads/2023/10/2024-Kawasaki-Ninja-ZX-4RR-Wayne-7-1024x576.jpg)
By now I was starting to have reasonable pace through the blind turn three, clipping the apex just under the bridge. And holding decent speed down the back on the faster section of the track. Looking at my Forcite helmet footage I was seeing mid 170s after the left hander, before rolling off then tipping right, knee kissing the ripple strip on the apex.
Interesting approach to that one, with no visible reference points on the track, I was looking for spots in the gravel on the track edge instead. Now obviously we were there to test a bike and have fun, not set lap records, but it was tempting to pull the pin properly…
![Kawasaki Ninja ZX-4R](https://www.mcnews.com.au/wp-content/uploads/2023/10/2024-Kawasaki-Ninja-ZX-4RR-Wayne-4-1024x647.jpg)
The whole track was taken without even needing fifth gear, yet we were still hitting mid 180s down the front straight… So it would have to give 240 a nudge… surely? That’s plenty quick on a 400!
And then there’s the price. Thirteen grand for a bike that is a proper small capacity sportsbike with a screamer engine, not a pretender. A genuine member of the ZX family. A rightful little brother to the 6 and 10.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2024-Kawasaki-Ninja-ZX-4RR-Wayne-14-1024x542.jpg)
That’s a bargain in my eyes. Do you go for the RR or save over a grand on the R? For the road the R would be fine for most. But there’s no denying the quick-shifter and improved suspension make for a better bike.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC00389-1024x683.jpg)
So, what do I think? I think it’s the perfect bike for a one make starter series… Which is exactly what they’re going to be doing over in the BSB I believe. Cheap, usable, good build quality. Bring it.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC00378-1024x683.jpg)
And I think it’d make for a great step up from your LAMS bike to a proper sportsbike. Us bigger, heavier, blokes (I’m 85 kg) have a few choices when it comes to road sportsbikes, but I reckon if you were sub 75 kg, and wanted to do a few track days and skill up… this could be just the ticket.
I tell ya what though… the ex-club racer in me can’t help but think this would be an awesome option to get back into it with a dedicated 400 track bike and find a club with a 400 cc class.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC00598-1024x683.jpg)
Don’t just take my word for it though, I expect Champions Ride Days (who ran the day for us at Morgan Park) will have some 400s in their hire fleet pretty quickly… Get a few of your mates together and get those knees in the breeze.
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC00411-1024x683.jpg)
I like the Kawasaki ZX-4RR because:
- It’s just so usable and confidence inspiring
- Works as a balanced package really nicely
- Proper top level sportsbike build quality in a 400
![Kawasaki Ninja ZX-4R](https://www.mcnews.com.au/wp-content/uploads/2023/10/2023-Kawasaki-Ninja-ZX-4RR-DSC04776-1024x683.jpg)
I’d like the Kawasaki ZX-4RR more if:
- Dash and mode controls aren’t the most intuitive, but you’re probably not going to be changing modes much to be honest
- I know it’s hard to keep weight down these days, but I can’t help but think about it. Even dropping 10 kilo would improve the power to weight even further.
- If I had a local track close by that I could do some track days with mates… Hurry up and build the track at Avalon already!
![Kawasaki Ninja ZX-4RR](https://www.mcnews.com.au/wp-content/uploads/2023/10/2024-Kawasaki-Ninja-ZX-4RR-Wayne-9-1024x576.jpg)
2023 Kawasaki ZX-4R & ZX-4RR Specifications
2023 Kawasaki ZX-4R Specifications | |
Engine | Liquid-cooled, 4-stroke In-Line Four, DOHC, 16 valves |
Bore x Stroke | 57.0 x 39.1 mm |
Capacity | 399 cc |
Compression | 12.3:1 |
Power | 55 kW (74 hp) at 14,500 rpm |
Torque | 37.6 Nm at 12,500 rpm |
Induction | Fuel injection: ø34 mm x 4 Forced lubrication, wet sump Electric |
Final Drive | Chain |
Gearbox | 6-speed, return (quick-shift on KRT edition) |
Clutch | Wet multi-disc, manual |
Frame | Trellis, high-tensile steel |
Fork (R | ø37 mm inverted fork (SFF-BP) with top-out springs |
Fork (RR) | ø37 mm inverted fork (SFF-BP) with spring preload adjustability, and top-out springs |
Shock (R | Horizontal Back-link, gas-charged shock with spring preload adjustability |
Shock (RR) | Horizontal Back-link, BFRC lite gas-charged shock with piggyback reservoir, compression and rebound damping and spring preload adjustability, and top-out spring |
Rake/Trail | 23.5°/97 mm |
Tyres | 120/70ZR17M/C (58W), 160/60ZR17M/C (69W)Â |
Front Brake | Dual semi-floating ø290 mm discs, Dual radial-mount, monobloc, opposed 4-piston |
Rear Brake | Single ø220 mm disc, Single-piston |
Wheelbase | 1,990 mm |
Width | 765 mm |
Height | 1,110 mm |
Wheelbase | 1,380 mm |
Clearance | 135 mm |
Seat Height | 800 mm |
Curb Weight | 188 kg |
Fuel Capacity | 15 litres |
RRP | $11,894 +ORC (KRT edition as tested $13,294 +ORC) |