2024 · Supersport · Buyer's Guide
Four Cylinders, Four Hundred Screaming CCs
Kawasaki built this one around a liquid-cooled inline-four that displaces 399 cc and makes 77 hp at 14,500 rpm. That figure tells you everything about its intent. Peak torque of 29 lb-ft arrives at 13,000 rpm, so the character comes from revs rather than shove, and the six-speed box with its up-and-down quickshifter exists to keep you inside that band. The support package is properly modern for the size: ABS, traction control, ride modes, a TFT display, and suspension that adjusts at both ends. A four-cylinder this small is a rare thing, and the sound alone is a legitimate reason to want it.
On the road it rewards commitment. Ride it lazily and 29 lb-ft is exactly as modest as it sounds. Work the gearbox and keep the needle in the top third of the tach, and the same motorcycle feels completely alive. At 417 lb wet it is not featherweight, and the 31.5 in seat with a committed riding position points at a rider who wants sport riding, not errands. It suits canyon and back-road riders who enjoy the process of riding well. The honest caveat: if you want easy roll-on thrust or a bike that forgives lazy shifting, look elsewhere.
Spec sheets don't ride bikes, but they set the baseline.
| Power | 56 hp (42 kW) @ 14,500 rpm (US; 77 hp / 57 kW EU) |
|---|---|
| Torque | 29 lb-ft (39 Nm) @ 13,000 rpm |
| Displacement | 399 cc400cc Motorcycles → |
| Engine | Inline-fourMotorcycles With Inline-Four Engines → |
| Cooling | Liquid-cooled |
| Gearbox | 6-speed |
| Front tire | 120/70-17 |
| Rear tire | 160/60-17 |
| Seat height | 31.5 in (800 mm) |
| Wet weight | 417 lb (189 kg) |
| Fuel capacity | 4.0 gal (15 L) |
Equipment check
Chassis
Connectivity
Drivetrain
Safety
None of what follows comes off a spec sheet. It's what I've picked up over years of listening: paddock conversations, parking-lot talk after a ride, club nights, and the notes riders send me once they've put a season on a bike. On the ZX-4RR the chatter settles into one clear pattern. Riders are hooked on what happens at the top of the tach, and they've made peace with the work it takes to live there.
The high-revving four dominates the conversation. Owners describe a top-end rush that keeps climbing toward 15,000 rpm and pulls them into a corner-speed rhythm, and they bring up the sound just as often, calling it something no parallel-twin rival can match. Handling draws the same steady praise: balanced, stable, quick to turn, and confidence-building on the street and at track days, even with suspension that riders say is set soft.
The recurring gripe sits below the powerband. Riders report the bike feeling gutless under 8,000 rpm and say keeping pace means constant work through the gearbox. Taller owners regularly call the cockpit tight, with low clip-ons and a low screen leaving little room to tuck in.
Spark plug damage during manufacturing causing unstable idle, hesitation, and stalling
During assembly, a tilted spark plug installation tool applied lateral force, cracking some spark plugs. This can cause rough idling, hesitation, and potential engine stalling. Kawasaki issued a safety recall to replace all four spark plugs. Affected units were produced between January 11 and November 14, 2023. Approximately 1,579 bikes involved in US recall.
Where this Kawasaki Ninja ZX-4RR pulls ahead of — or falls behind — its rivals on the numbers, and the typical bike in its class on character.
Power
Torque
Displacement
Wet weight
Seat height
Forget spec-sheet bragging. Here's who the Ninja ZX-4RR is actually built for.
This is your kind of road. It carves precisely, holds a line, and the engine rewards the skill you already have. Just accept that you will be shifting constantly to keep it singing.
Made for Angeles Crest Highway · Coronado Trail Scenic Byway · Big Sur Coast Highway
Brilliant once the road starts twisting, less friendly on the highway miles that get you there. No cruise control and a committed riding position make the transit stretches the price of admission.
Made for Texas Hill Country · Texas Hill Country BDR-X · Twisted Sisters
If you ride for precision rather than speed, this rewards it. Light handling and generous lean clearance suit repeat runs on tight technical roads, and the engine keeps you fully involved.
Made for Tail of the Dragon · Back of the Dragon · Blue Ridge Parkway
If this one isn't quite the fit, these are the bikes worth riding back-to-back against it.
Any price note compares both bikes at the same age — the youngest age both have on the used market — against this Kawasaki Ninja ZX-4RR. “cheaper/pricier” is what that bike costs second-hand, not how worn it is.
Compare it with every bike that shares the same spec or equipment.
