2023 Kawasaki Ninja ZX-4R vs Ninja 400: Five Key Differences

Kawasaki has just dropped the bombshell Ninja ZX-4RR for 2023. The sportbike is an ode to four-cylinder, entry-level screamers of yore, and aims to highlight Kawasaki’s modern engineering prowess. However, Team Green already has the Ninja 400 in its portfolio–a global hit, thanks to its peppy performance, likable ergonomics, and affordable price point. So what exactly does the new Ninja do differently? Well, allow us to explain.

Updated September 2023: As new information about the motorcycles and updates comes to light, we will update this article periodically. After all, we want nothing but the best of our audience.

RELATED: The New Kawasaki Ninja ZX-25R Is More Powerful Than The Ninja 400!

Kawasaki Ninja ZX-4R vs Ninja 400: Performance

When you look at their names, there’s just a “ZX” to differentiate the two Ninjas. But this moniker is no joke since all “ZX” wearing Ninjas employ four-cylinder engines. The ZX-4R is no exception, debuting an all-new 399cc, four-cylinder mill which screams out 76 horsepower at over 14,000 RPM. On the flip side, the Ninja 400 employs a 399cc, parallel-twin engine to gush out just 45 horsepower – a 31 pony deficit from the ZX. The inline-four mill also benefits from a higher compression ratio (12.3:1 vs 11.5:1) and bigger throttle bodies (34mm vs 32mm), resulting in a manic 16,000 RPM redline, compared to the 400’s 13,000 RPM.

However, the story is a bit different in America. You see, Kawasaki has limited the US-spec ZX-4RR to just ~56 horsepower. The power comes in at 11,500 RPM to keep American noise emissions in check. Still, the figure is considerably more than the 400.

Kawasaki Ninja ZX-4R vs Ninja 400: Features And Electronics

The Ninja 400 has been on sale for nearly five years, yet it has undergone no significant updates. This especially shows in the features department, as it boasts just a digi-analog readout, dual-channel ABS, and slipper clutch. In contrast, the ZX-4R is the newest Ninja in the lineup and has the technology to match. Riding modes, traction control, bi-directional quickshifter, power modes, smartphone connectivity—you name it and the Ninja ZX-4R has it. Plus, all this is accessed by a 4.3-inch TFT instrument cluster, loaded with a dedicated track display mode, just like the Ninja ZX-10R. Not to mention, this makes the ZX-4RR one of the most loaded sub-500cc bikes in America.

Kawasaki Ninja ZX-4R vs Ninja 400: Underpinnings

RELATED: The Manic Kawasaki Ninja ZX-4RR Just Went Faster Than A Yamaha R7!

The same story follows with underpinnings department, too. The Ninja 400 feels quite vanilla, courtesy of its non-adjustable telescopic forks, monoshock, and single disc brakes at both ends. Whereas the ZX-4R is all things top-shelf. You get adjustable Showa SFF-BP forks up top, alongside two 290 mm disc brakes. The rear end comprises a Showa BFRC monoshock, in addition to a single 220 mm disc brake. It’s not all hunky-dory, though, as the ZX-4R weighs 49 pounds more than the Ninja 400. This is backed up by the ZX’ longer length, wider body, and 0.3 gallon bigger fuel tank than the N400. Differences aside, both motorcycles are built around a steel trellis chassis.

Kawasaki Ninja ZX-4R vs Ninja 400: Design

Both motorcycles are handsome and fit well in the Ninja family. They have identical ZX-6R-like headlights and a ZX-10R-derived tail section, but the ZX-4R feels fuller and brawnier than the Ninja 400. If you want more colors, though, it’s the Ninja 400 that gives you more variety, while the ZX-4R only comes in Kawasaki’s KRT livery. Design is a subjective affair, so make of that what you will.

Kawasaki Ninja ZX-4RR Colors

Kawasaki Ninja 400 Colors

• Pearl Blizzard White
• Metallic Magnetic Dark
• Metallic Carbon Gray

Kawasaki Ninja ZX-4RR vs Ninja 400: Price

Thanks to the aforementioned bits, it’s quite clear the Ninja ZX-4RR is the more premium, better-equipped motorcycle between the two 400cc Ninjas. And all this comes at a sky-high price of $9,699–$4,400 more than the Ninja 400, and just $1,000 shy of the 2023 Ninja ZX-6R’s MSRP.

Now, we know that’s some serious money for a 400cc motorcycle, but we believe the ZX-4RR packs enough punch to justify it—at least to an extent. Plus, it is targeted toward hardcore motorcycle enthusiasts who want an unmatched riding experience, and not necessarily the “ideal” motorcycle. So tell us, if you had $9,699 to spare, would you pick the RR? Or are you settling for the Ninja 400?