2018 Kawasaki Ninja 400

Editor Score: 85.25%
Engine 18.25/20
Suspension/Handling 13.0/15
Transmission/Clutch 9.0/10
Brakes 7.0/10
Ergonomics/Comfort 8.5/10
Appearance/Quality 8.5/10
Desirability 8.5/10
Value 9.0/10
Overall Score85.25/100

Kawasaki may have just found the sweet spot with its new Ninja 400. At a glance, the new motorcycle has undergone a substantial weight reduction treatment, a displacement boost of 103cc, and a sexy styling redesign – all while remaining at the exact same price point. Non-ABS models start at $4,999 while ABS is an additional $300. Kawasaki was out for blood when it went back to the drawing board for its new entry-level motorcycle.

2018 Kawasaki Ninja 400: Exclusive Dyno Run And Measured Weight!

When Kawasaki started to feel the stark competition from bikes like Yamaha’s R3 and KTM’s RC390, they got to work in order to “take back what was theirs,” according to Kawi. That would be the lightweight entry-level sportbike category. With one look at the side by side spec chart, it’s pretty obvious they have done so. After spending a day riding the new Ninja 400 on the winding back roads of Sonoma County and a day of spinning laps at Sonoma Raceway, I am here to report that the 2018 Kawasaki Ninja 400 will be a force to be reckoned with in the lightweight sportbike class.

So, where to start…

Engine: More CC’s, please

Kawasaki Ninja 400

Ah, the age-old-adage: There’s no replacement for displacement. While this isn’t always the case, maybe it is more often than not. Kawasaki has boosted the cubic centimeters of its smallest Ninja by 103cc, putting it atop the spec chart when side by side with its classmates. Still a parallel-twin, bore and stroke are increased to 70.0 x 51.8 while compression ratio is bumped to 11.5:1 from 10.6:1 found in the 300.

Engine performance revisions can be seen throughout, including larger diameter head pipes at 31.8mm, a lighter flywheel, more precise tuning allowing for the elimination of sub throttles, lighter forged camshafts, optimized intake and exhaust valves, a new piston with reduced squish and a flatter crown which is also made to be lighter thanks to the oil jets cooling it from below. The cylinder is also sleeveless and uses plated bores.

The radiator has also been redesigned to better direct heat away from components the rider will come into contact with, all while using no new parts says Kawasaki.

Kawasaki Ninja 400

Impressively, Kawasaki has managed to increase displacement and optimize performance, all while keeping the engine relatively the same size as the 2017 Ninja 300.

Kawasaki Ninja 400

The new downdraft intake provides the most direct path of air into the cylinder for a more efficient intake system.

Also attributing to the not-so-wee Ninja’s new-found performance is the larger 5.8-liter airbox with a new downdraft intake which provides the most direct path of air into the cylinder. This creates a more efficient intake system. The intake funnels themselves are different heights allowing Kawasaki to tune out most dips in the torque curve. Kawasaki says this has been especially important to improved engine performance at high rpm. The airbox was also engineered with more rigidity at the top to eliminate unwanted noise, while still delivering a clear intake note which was present in the best way at high rpm at Sonoma Raceway.

Kawasaki Ninja 400

As we can see on our exclusive dyno run of the Ninja 400, the torque curve is impressively flat, peaking at 25 lb-ft of torque at 8,000 rpm. Perhaps more notably, is the fact that 20 lb-ft are available just under 4,500 rpm. Horsepower is also substantially increased from the previous Ninja, as well as the competition, with 44 hp available at 10,000 rpm.

Beginner-Ish Sportbike Shootout + Video

The transmission has also undergone some revision. Close gear ratios and the assist clutch make flipping through gears a breeze, while the slipper function will prevent the rear tire from hopping or skidding during aggressive or accidental downshifts. Kawasaki says the pull at the clutch lever has been reduced by 20% which may be welcomed on the street; however there were times during our track day when it was difficult to feel the engagement point.

Handling: Fully Flickable

Kawasaki Ninja 400

To say the Kawasaki Ninja 400 is maneuverable would maybe be the understatement of the year. As I picked the bike up off of its kickstand it became clear just how lightweight the Ninja 400 was. A few corners later it was apparent how much fun I was about to have for the next two days. The usable mid-range power, light clutch pull, and ease of handling make for a fun and unintimidating entry-bike for those looking to begin their foray into motorcycling.

Let’s take a look at how Kawasaki made an already agile motorcycle into a razor-sharp, apex-mauling, corner-killing, Ninja.

Kawasaki Ninja 400

When considering the power-to-weight ratio of motorcycles, dropping 15 lbs provides a substantial boost in performance. When we had the Ninja 400 on the dyno we also had a chance to weigh it. Full of 3.7 gallons of fuel, the 2018 Kawasaki Ninja 400 with ABS weighs 366 lbs. The last Ninja 300 we tested, with a 4.5-gallon tank, weighed 381 lbs, so we’re looking at about a 10-lb drop in real weight.

Kawasaki Ninja 400

Although I touched on the engine’s weight savings earlier in this article, weight reducing efforts can be found throughout. The new Ninja 400 is built around a trellis-style frame derived from Kawi’s work on the Ninja H2, which adds rigidity while reducing weight. The rigid-mounted engine is also now used as a stressed member, with an aluminum swingarm mounting plate bolted to the back of the engine. This all leads to added stability and less weight.

Kawasaki Ninja 400

A quick look at the Ninja 400’s new chassis dimensions also allude to the nimbler character of the 2018 model. The overall wheelbase has been shortened by 1.4 inches, while the steering angle has been decreased by 2.4 degrees putting rake and trail at 24.7°/3.6 in. Seat height has been kept the same at 30.9 inches. The rather upright “clip-ons” set the handlebars back toward the rider by 15mm from the previous model, while the footpegs have been moved 9mm backward.

All things Kawasaki on Motorcycle.com

The suspension has also been upgraded with a non-adjustable 41mm Showa fork from the Ninja 300’s 37mm tubes. A KYB rear shock with a new Uni-Trak linkage is now used out back with five-way preload adjustment. While the suspension is somewhat soft, I never had any bottoming issues, and it soaked up imperfections on the street quite nicely. On the track, stiffer suspension would be preferred, yet it worked well enough for us to thoroughly enjoy the bikes at Sonoma Raceway.

Kawasaki Ninja 400

Kawasaki has also upgraded the Ninja’s stopping power up front to a single 310mm rotor clenched by a dual-piston Nissin caliper, while the rear rotor remains 220mm with a single-piston caliper. Although braking power was adequate, it became one of the few things most journalists said they would change first if track-duty was the assignment. Steel braided brake lines and a set of racing brake pads would likely fix the sponginess and soft initial bite. On the street, it’s not so much a problem. I did overhear other much faster journalists complain about brake fade (cough* Ari Henning *cough* lap record holder at Sonoma Raceway in the 300 class *cough). I didn’t have that issue.

While revising the entire motorcycle, Kawasaki didn’t forget the tires. The Ninja 400 now uses Dunlop Sportmax GPR300 rubber, which provided good grip on the street in dry and damp conditions and wasn’t bad at Sonoma Raceway either.

Style for miles

Kawasaki Ninja 400

Since 2008, Kawasaki has done a great job at making its entry-level motorcycles look much more like their larger displaced siblings. For 2018 Kawasaki has continued with styling that is undeniably Ninja.  

Kawasaki Ninja 400

From the KRT graphics (a $500 upgrade that includes ABS), to the trellis-type frame and tail’s triple-peak motif, the Ninja 400 shares styling and spirit with its bigger bros. LED lighting is found throughout on the Ninja, giving it that premium motorcycle feel. As mentioned previously, the triple-peak motif tail section and small chin spoilers on the bottom of the front cowl were derived from the Ninja H2.

Kawasaki Ninja 400

The new five-spoke wheels look slick and are said to be lighter than the previous version.

Kawasaki Ninja 400

The cockpit also has refined feel without loose cables or wires hanging around obtrusively, rather everything is well bound and routed neatly out of the way. The dash also looks great while providing a decent amount of information with the gear-selection indicator front and center. In harsh sunlight, the screen can be rather difficult to read.

The Verdict

Kawasaki Ninja 400

There seems to be some confusion about the 2018 Kawasaki Ninja 400’s place in the market and Kawi’s line-up. First, Kawasaki will no longer produce the Ninja 300. A lot of folks seemed to think it would continue the 300, but this is not the case. The 400 is now Kawasaki’s smallest sportbike. 

Kawasaki Ninja 400

Secondly, this isn’t a bike you’ll get tired of in a week! There are so many comments on Kawasaki’s social media channels coming from guys saying things like: Smallest bike I would suggest for a beginner is a 600, or condescending remarks like, Who’s buying these cute lil things. What happened to men? … Those are real comments from Kawasaki’s Facebook page on the promotional video with Tom Sykes and Jonathan Rea. While I would like to go on a rant about this, I’m going to leave it at that and let you folks duke out your feelings about it in the comments section.

Kawasaki Ninja 400

Final thoughts on the Ninja 400: It’s a more versatile, unintimidating lightweight sportbike that motorcyclists can grow with. The Ninja 400 would be an easy first motorcycle that you could get into track days with as well. To me, and many others who have ridden the 400, the boost in displacement feels just right. You have easy-to-use mid-range power that comes on strong without being intimidating, incredibly light and precise handling, and styling for days. And guess what?! They are in dealerships now, so seek out your local dealer or demo day and have a look for yourself. 

Kawasaki Ninja 400

What do you think about the increasing displacement of the lightweight sportbike class? Let us know in the comments section. Also, if there is anything I haven’t addressed in this article that you are curious about, leave a comment and I will get you an answer as soon as possible.

In Gear

Kawasaki Ninja 400Street
Helmet: AGV Corsa (No longer in production)
Jacket: Dainese Super Speed Textile Jacket
Pants: Dainese Over Flux Overpant
Gloves: Racer Gloves Sprint
Boots: Alpinestars SMX Plus Boot

Kawasaki Ninja 400Track
Helmet: AGV Corsa (No longer in production)
Suit: Alpinestars GP Plus V2 Leather Suit
Gloves: Alpinestars Supertech Glove
Boots: Alpinestars SMX Plus Boot
Back Protector: Dainese Manis D1


  • Brian Cordell

    If the 400 had existed a decade ago, I might still be on it. This lightweight won’t solve the Great Plains crosswind touring woes, but I can see it as a fantastic urban solution!

  • Starmag

    “Come on down, you’re the next contestant on The Price Is Right !”

    As far as the “Who buys these cute little things” comments go, I’m thinking of trading down from my 122HP ZRX because it’s fast enough that if I really whip on it though a few gears, I’m severely breaking the law and the penalties for more than 15 mph over are getting rather severe. Losing your license is a real drag, ask me how I know. I’d want a RS version of this though.

    It’s more fun to ride a slow bike fast, than a fast bike slow.

    • Born to Ride

      Nah, this bike needs an Eddie Lawson version like your ZRex. That would be awesome.

  • Nice writing, Ryan. I’m looking forward to the Z400.

    • Robert Smith

      … and the Versys-X 400.

  • StripleStrom

    I think they finally found the sweet spot. This 400 has what is probably the widest appeal of any sport bike in their lineup, appealing to both beginners, and also more experienced riders looking for a light-weight and capable track or canyon bike. The 250 and 300 just didn’t have the torque necessary for a typical full-sized rider. This is what many have been waiting for. I bet they sell like crazy.

    • Mary

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  • Kahless01

    the smaller gas tank kinda sucks. i like my 5gal on my bike. but even with that if im riding down to the coast against a bitch of a wind i barely make it from san antonio with a gallon left. i might speed a little tho.

  • Martin Buck

    When growing up (most people who know me would say I utterly failed in that regard) I graduated from a 100cc twin to a 250 twin, and I managed to tour the country on that bike. I moved onto a 350 twin (hated it) then a 350 single (loved it), and I was happy at that level. I could beat most larger bikes over a mountain road, and it was so light it became an extension of my body. I had numerous other larger bikes later on, but none had the charm and ease of use of the 350/400 level of bikes. This Kawasaki is going to become the measure by which we judge all other bikes.

  • Jon Jones

    Lovely Marin County. Heaven when traffic is light.

  • Gabriel Owens

    I wonder how it would enjoy supporting my 6’1″ 240 pound body.

    • Matt O

      probably fine, i’m about 225 and my old ninja 250 never had any problems. i can’t speak to the 6’1″ part though

  • john phyyt

    Okay .. Maybe Expecting too much BUT. Z900 produces 115 on dyno . doing math this bike “should” give 51hp. like 44 is good , but, maybe I am expecting the world. .. This is a sports bike . A little “peakiness” would have been okay.

    • Born to Ride

      Two more cylinders make a big difference on specific horsepower of an internal combustion engine. If this thing was a 400cc screaming i4, she’d be pushing 60-70hp to the wheel at 18,000rpm. That doesn’t make for a very Street worthy bike though.

      • john phyyt

        I remember the I4 400’s from Japan.. COOL. .. Old RVF 400 Honda is still SEX. Unlikely to be $4999.

        • Born to Ride

          Indeed. On all counts.

          • john phyyt

            Interesting that this bike is . Cheaper ; lighter; faster; better handling; smoother and simply superior in every objective way to new R.E. 650 twins. And yet !

    • Xenomir

      Ninja 650, which also has a parallel twin, makes 9.23 whp per liter, and the FZ-07 makes 9.66 whp per liter

      The Ninja 400 makes 11 whp per liter, the Ninja 300 made 11.66 whp per liter, and the 2008 Ninja 250 made about 10 whp per liter. So the Ninja 400’s engine seems to be pretty tuned, though a bit less so than the 300. At most, you could say it “should” make 46 whp compared to the 300.

  • Craig Hoffman

    Looking at the dyno chart, the top end looks “cut off” with that long slowly descending flat plateau past the peak vs. a sharp drop that usually indicates the airbox has run out of capacity, the cam timing has given up, and the exhaust is stuffed up past those engine speeds. In contrast, the 400’s dyno chart suggests the bike wants to make more power, but it was reigned in. The long flat plateau after the peak is is usually indicative of artificial limiting of power via electronic means. Why would Big K do that? Probably to keep the bike legal for markets with tiered licensing, where it should be a big hit.

    I bet some ECU “Unleashing” and a pipe gets this puppy into the high 40s maybe even 50 hp. Throw a light free breathing pipe, fueling mods, brake line/pad upgrade and some suspension work, and this little guy would be a sweet “wringable” track day bike.

    Ya, you could “just buy a 600” for less. Problem with that is 600s are no fooling around rip your arms off 14,000 RPM screaming fast machines. This 400 looks fun and frolicky in comparison. Some just wanna have some fun, not be riding a screaming fast bike that is frustrated to not be going 150 mph.

  • TronSheridan

    Are we ever going to get an “official” H2 SX review?

    • Ryan


  • FreeDominion

    My wife bought one this past weekend and she loves it. I’ve only taken it around the block, but I can definitely see a lot of fun with this bike, and that’s coming from a guy who’s daily rider is a Moto Guzzi griso 1100. Being only 125 lbs, she’ll have more fun than I, at 185 lbs, but it seems plenty fun to me. https://uploads.disquscdn.com/images/432cbfb8e01c35bfedbfec318c179cae0b4eae6afc4953362417a46b70443607.jpg

    • StripleStrom

      I like the blue. The solid colors give it a legitimate “grown up” look. Get your wife to post a review on here when she has time.

      • FreeDominion

        Definitely agree about the solids rather than the graphics. Heavy graphics look sophomoric to my eye. A combination of subtle or bold contrasting colors though, done right, looks the business. The blue is beautiful in the sun, shining a kind of pearl-metallic. She already has a TST fender eliminator and other parts on the way.

    • gerry3273

      Nice TU250X in the background!

      • FreeDominion

        Thanks! That was her first bike, which the 400 replaced. Now it will go on craigslist. We dropped as much weight from the tux as we could, just to squeeze a bit more out of it. Smaller front fender, aftermarket muffler, removed the rear fender and seat, then I turned the rear fender support loop into a cargo rack by riveting aluminum mesh to the underside of the loop, hammering it up from the underside to give it a concave curve, and attaching elastic buckle straps to hold down whatever needed to be carried.

  • gogiburn


    • gogiburn



        • Born to Ride

          That’s “DANK WHOOLIES” bruh. Check your vernacular.

          • Rocky Stonepebble


  • Bmwclay

    So this ‘new’ 400 is the old ‘500’?

    • Born to Ride

      Except lighter, more powerful, and insanely better looking. Another way to look at it as the new 650 is the old 500, and this is just the better Ninjette.

  • John Gregory

    Wow… They’ve almost reinvented the ’84-’86 VF 500F Interceptor.

  • Rick Vera

    I love this! Now where’s my Versys-X 400, please.

  • Jon Neet

    As a 64 year old biker having ridden for 56 years, I still look back fondly on an old Ninja 500 I owned years ago. Oh, and the fine beater GPZ550 I rode for a time. This new 440 looks like another winner for Kawasaki.

    • Rocky Stonepebble


  • Old MOron

    “There are so many … condescending remarks … real comments from Kawasaki’s Facebook page…”

    Rubble is over there, too, huh?

  • ooobaby44

    Is there a place to lock your helmet to the bike and are there bungs where you can attach bungee cords to carry things on the pillion seat etc?

  • tpcs

    381 pounds of the ninja 300 at full wet weight minus the 366 full wet weight of the ninja 400 is a difference of 15 pounds..not 10 Motorcycle.com’s final editor.

    • Rocky Stonepebble

      It’s ten in metric.

      • tpcs

        381 pounds is the weight of the Ninja 300. Metric would be whatever that is converted to KILOGRAMS. So no. It’s imperial.

    • Ryan

      I think the final editor’s comment was to not give Kawi too much credit for dropping weight when approximately five pounds may have been in reducing fuel tank capacity.

      • tpcs

        No offense to you, but I couldn’t care any less about the editor wanting or not wanting to give credit or discredit. When it comes to facts, they need to stick to the facts. If I wanted to deal in misinformation, I’d go straight to the dime a dozen bought off and paid for lame stream news media of NBC, cbs, abc, fox, and a few others. OAN seems solid, but I try now to watch the news unless it’s for local weather and any guaranteed robberies that happen in the Jackson MS areas …..daily for the past 40 years.lol.

  • Patriot159

    Next year Yamaha fights back with an R4.5! Honda a CBR 425! I know, a 600 will beat them all! Let’s make that!

  • XRayHound

    WERA is sticking these in D Superstock, so the 300 and R3 are still the go-to for people like me that like to race E. Kinda glad, I like this bike but I wanted to stay with Yammie.

  • DisqusThis

    What’s the tank range since it lost so much capacity?

    • Ryan

      Since we don’t have real world mpg yet- The display says an average of 50 mpg. So, approximately 185 miles.

  • Xenomir

    Funny thing about the guys who insist on 600cc+ (I’ll assume we’re not talking supersports, because that category is laughably pointless off the track and ostensibly dead at this point for excellent reasons–Street triple stomps any 600SS) is that the Ninja 650 has a barely superior power-to-weight than this Ninja 400. I’d love to see a 110 pound female rider easily pull on a 180 pound dude in a “600+”

    Personally, I’ll take 60-80 weight reduction over a ~20% better power-to-weight any day–not to mention a few extra grand in my pocket.

  • Jay Moto

    Yeah the massive tool bags who say those quotes get their’s everyday just simply having to live their horrible, inadequate lives, so let ’em talk. Also, anyone bashing Kawi by saying this 400 is now too big, need to realize that this thing is probably actually easier to ride for beginners now than the 300 and 250 before it. The peak horse number is increased yes, but the increased displacement gives Kawi so much more power spread to work with, allowing them to sort of “fill in” the power at low revs, which will make letting the clutch out and taking off even easier. I think it’s a total win/win.