2018 Kawasaki Ninja 400 | FULL TEST

Rennie Scaysbrook | February 22, 2018

2018 Kawasaki Ninja 400 | FULL TEST | The junior Ninja in the Kawasaki sportbike range is back—bigger, and tougher than before. Is this the new benchmark in the junior supersport segment?

Little bikes are fun. Big, big, fun.

The above statement should come as no surprise to anyone who has spent more than five minutes on a Kawasaki Ninja 300, the bike now unceremoniously booted into history by the all-new, 2018 Ninja 400.

The 300 was one of those bikes that taught riders how to extract every ounce of available performance—it served as an exercise in maximization—and those riders who learned the ways of the Ninja, especially at a young age, were in very good stead for their riding careers, either on the track or on the street.

Click here to read this in the Cycle News Digital Edition Magazine.

Photography by Kevin Wing and Brian J. Nelson

The 300, however, has served its purpose, and for 2018 it has been replaced by a new Ninja in the 400. Starting at $4999 for the non-ABS version and increasing to $5499 for the KRT liveried bike we tested, it’s not just an increase in capacity, horsepower and torque that 400 riders have at their disposal; there’s an all new chassis that weighs a claimed 17 pounds less than the 300’s, as well as a significantly larger front brake disc and totally revamped styling much more in line with the big brother Ninjas in the ZX-6R and ZX-10R.

It’s all part of keeping the bloodline flowing, with the new 400 a much worthier machine when you think of the extreme performance differences that come from jumping from a 400 to a 600 to a 1000.

Punching above its weight

Our chance to test out the new Ninja 400 came at the national press intro, conducted around the rolling hills of Petaluma, California, and a day around the divine bends of Sonoma Raceway—the perfect venue to exploit the new Ninja’s strong points.

However, before we start, there’s an elephant in the room we must address. Much like the Ducati Panigale V4 S we tested a few weeks back, the Ninja 400 is substantially larger than its competition in terms of capacity. At 399cc, there’s a 100cc advantage over the similar parallel-twin configuration of the Yamaha YZF-R3, with the KTM RC390 sitting at 375cc but with one cylinder less.

The twin-cylinder Honda CBR500R is actually the largest machine in the junior supersport segment at 471cc, but suffers from a huge weight disadvantage compared to the Kawasaki, with a claimed curb weight of 423 pounds over the Kawasaki’s claimed 366-pound curb.

At that weight and with Kawasaki Europe claiming 45 horsepower at 10,000 rpm for the new Ninja 400 (Kawasaki USA wouldn’t give us official claimed power and torque figures), the Ninja 400 has a clear advantage over the rest of the competition in the spec sheet even before a key is turned and a starter thumbed.

On the street, this translates to a much easier bike to ride than the something like the outgoing Ninja 300 or the excellent YZF-R3, simply because there’s more midrange torque available over a wider rev range. Here the 400 is a revelation, with good, usable torque from 5000-9000 rpm, meaning you don’t need to rev the parallel-twin as hard as its opposition it get meaningful drive and, you more often than not, find yourself in a higher gear in the close ratio six speed ’box than you’d expect, letting the engine pull you from corner to corner.

And to the sportbike rider’s delight, the extra capacity afforded to the 400 also makes for a better track weapon. This is still a bike you need to rev hard if you want ultimate, track level performance—around somewhere like Sonoma Raceway you’re very rarely doing anything other than full brakes or full throttle on a little bike—but the ride is less tiring, less intense than on the 300. This factor is not doubt a by-product of the slip and assist clutch, fitted as standard to the 400. You can bang down the gears pretty abruptly and the clutch will just take care of business, reducing the chances of the rear wheel locking up and making corner entry smoother.

The engine is helped in that it enjoys a beautifully smooth throttle response—there’s not a lot of power being pumped out so a smooth throttle should be a given—and there’s no variable ride maps on the 400. Not that it needs it.

Come to think of it, there’s no electronic rider aid whatsoever aside from the optional ABS model, so it’s all about seat-of-the-pants feel, rather than electronic intervention, when trying to go fast on the track.

A good mate of mine, Road Racing World’s Chris Ulrich, himself a former AMA Superbike weapon, said it best about the engine when we pulled in for lunch on day one: “This thing is just fast enough that an idiot like me is still entertained and I don’t feel like I’m about to lose my license.”

In that remark, Chris is spot on. The 400 motor is one that should be enjoyable to any level of rider—whereas the 300 was lacking the excitement more experienced riders craved, now the 399cc parallel-twin has the right mix of outright performance and everyday usability.

It will also make a great platform for racing. Who remembers the Aprilia Cup with those beautiful Aprilia RS250 two-strokes of the late 1990s/2000s? Those bikes had around 60 horsepoer on tap, and while the Ninja 400 isn’t quite going to top that legendary machine in terms of outright engine power, when put in race trim with good suspension and tires, the 400 should offer comparable performance for the first time from a junior bike since the 250 class finished early in the last decade.

Still a kid’s bike?

The Ninja 400 is still a physically small motorcycle, and it’s got a little smaller since the 300 in that the handlebars are now 15mm closer to the rider. This can make the ride a touch cramped if you’re over six feet tall, but the discomfort is minimal. You sit in this chassis rather than on it, with the way your legs fold into the tank and the deep dish seat putting you in a position that’s both comfortable for long days in the saddle as well as trackday sending.

The suspension gracing the 400 is basic, with unadjustable forks the same diameter at 41mm as the ZX-6R and preload adjustability only on the rear shock. The ride is soft for the most part, and the budget spec of the suspension does an amicable job of soaking up most of the crappy road surfaces we encountered around Petaluma’s rolling countryside.

Track day riders and racers will not doubt be upgrading the suspension quick smart, as anyone who really begins to cut a respectable lap time will hit the outer limits of the suspension very quickly.

It’s still surprising just how quickly you can push a box stock 400 around somewhere like Sonoma. Just ask Cycle World’s Ari Henning, who reportedly went only three and a half seconds slower on the road-going 400 than his own Sonoma lap record, set on an extremely worked and modified Honda CBR250R.

One of the big advantages over the 300 is the 400’s new 310mm front disc, up from 290mm. There’s more stopping power everywhere, but the front brakes also have this curious issue with a slight pulse when the lever is first engaged that no one at the test could figure out the solution to. Collective wisdom dictates it should be the ABS causing the issue, but as no non-ABS 400s where available for testing, and Kawasaki couldn’t tell us what the problem is, we were none the wiser.

The brakes are another area likely to receive an upgrade when it’s time to go racing, as the rubber lines would eventually induce a bit of fade after repeated heavy braking on the track. On the road, this issue was not encountered and brake performance remained constant throughout the test—a set of race-spec steel braided lines will solve this issue, no worries.

I sincerely hope this is the last capacity increase I see with the junior supersport category, because I feel this is as fast as this class needs to be. The junior class, ever since the Ninja 250 came out all those years ago, was a shadow of what it once was in the 1990s and early 2000s, and now the class, led by this new Ninja 400, is right where it needs to be in terms of outright performance.

That’s the other thing—this Ninja 400 is the same price (non-ABS) as the Yamaha YZF-R3 at $4999. That’s an awful lot of bike and performance for the money. Value for money with the Ninja 400 is absolutely brilliant, and the package on offer should keep riders enthralled for longer, rather than wanting to upgrade the second they feel they are ready.

It will be interesting to see what, if any, restrictions the Ninja 400 has to operate under in the new MotoAmerica Junior Cup category, because the machine has a clear advantage over the rest of the field over Yamaha’s YZF-R3, KTM’s RC 390 and Honda’s CBR500R in standard trim. CN

What’s it got, mister?

It’s not simply a case of boring out the 300’s cylinders to make the new Ninja 400 what it is. The parallel-twin engine has been extensively overhauled, so let’s dive into the changes.

Motor

Bore has been widened by 8mm and stroke lengthened by 2.8mm to give the 399cc capacity change.
Kawasaki has fitted a new downdraft intake, which they say is the shortest and most direct route for the incoming air into the all-new airbox. The downdraft-intake layout is claimed to improve cylinder filling, especially at high rpm, and helps eliminate space under the seat and thus make it easier for shorter riders to reach the ground.
Airbox itself has been increased by 1.1 liters to 5.8 liters, with the top of the airbox more rigid than the 300’s, so as to get more intake note under acceleration.
Unlike the 300, the 400 has unequal-length intake funnels to help smooth out dips in the torque curve.
Twin 32mm throttle valves are the same size as the outgoing 300.
Intake and exhaust valves measure 27.7mm and 23.5mm, respectively.
Forged cams are lighter than the 300’s.
Compression ratio has been upped from 10.6:1 to 11.5:1 thanks to a flatter piston crown.
Cylinder is cantered forward 20 degrees to reduce overall height and help with weight distribution.
Flywheel has been lightened to help the motor spin up faster.
The radiator fan has a new design that helps direct air directly downward to the road, which reduces the overall heat coming off the engine that reaches the rider.
The slip-and-assist clutch has reduced in diameter from 139mm to 125mm, which results in a much lighter pull at the lever than with the 300 clutch.

Chassis and Body

Trellis chassis has been reduced by 17 pounds compared to the 300’s.
41mm fork is 4mm larger than before.
Rear suspension has new linkage ratios to enhance rider feel.
310mm disc is the same diameter as larger bikes like the ZX-6R and ZX-14R.
Rear brake caliper is all new with larger dual pistons and a 220mm petal disc.
Five-spoke star wheel design is similar to the Ninja 650.
The 400’s bodywork has been designed to mimics the lines of the ZX-6R and ZX-10R more closely than the 300.
The front of the body under the lights now sports chin spoilers, similar to the Ninja H2 and ZX-10R.
LED headlights are a premium feature for this segment.
Tail section has the same triple peak design as the Ninja H2.
Seat height is the same as the 300, but the seat foam thickness is twice as much as the outgoing machine’s.
Same instrument cluster as the more expensive Ninja 650, with a gear indicator and remaining fuel range.

SPECIFICATIONS
2018 Kawasaki Ninja 400 ($4999 non ABS; $5499 as tested w/ABS)
Engine:	Liquid-Cooled, DOHC, 8-Valve, Parallel Twin
Displacement:	399cc
Bore x stroke:	70.0 x 51.8 mm
Compression ratio:	11.5:1
Clutch:	Wet multi-plate, assist and slipper type
Transmission:	6-speed
Chassis:	Steel trellis
Front suspension:	41mm conventional fork
Rear suspension:	Monoshock with preload adjustment
Front brake:	310mm disc, dual-piston caliper, ABS optional
Rear brake:	220mm disc, single-piston caliper, ABS optional
Front tire:	110/70-17 in.
Rear tire:	150/70-17 in.
Wheelbase:	53.9 in.
Seat height:	30.9 in.
Fuel capacity:	3.7 gal.
Weigh (ABS curb, claimed):	366 lbs.
Color:	Spark Black, Candy Plasma Blue, Pearl Solar Yellow/Pearl Storm Gray/Ebony, Spark Black, Candy Plasma Blue, Pearl Solar Yellow/Pearl Storm Gray/Ebony, KRT Edition Lime Green/Ebony