Kunihiro Tanaka is no stranger to designing motorcycles. He’s been with Kawasaki for two decades during which time he worked on the parallel twins that power the Ninja 650, Z650, Versys 650, and Vulcan 650. He was also the project leader for the Ninja 300 reboot that debuted in 2013. For the last three years, Mr. Tanaka’s world has revolved around developing the Ninja 400 that we recently reviewed in this article. Throughout the press launch Tanaka was curious to know what we thought of the new bike, but toward the end of the event we turned the tables and peppered him with questions about his latest creation.
Were the Yamaha R3 and KTM RC390 what you had your sights on while designing the new Ninja 400?
R3 yes, but not the KTM. It’s a single and the bike has a more track-focussed mission. Our target with the Ninja was wider, we wanted good track performance but daily riding on the street was more important. The R3 was our main target. It’s a twin. We view the singles like the KTM and Honda’s CBR300R as being in a different category.
The new Ninja’s frame is drastically different from the 300’s, with a shorter wheelbase and different geometry and structure. What was the objective for the 400’s chassis?
With the outgoing Ninja 300, we were still working with the 250 frame, which had become an old design. With the 400 we took the opportunity to create a new frame and swingarm. Shortening the wheelbase helps quicken steering and gives the bike sportier handling, and the swingarm is 10mm longer for better suspension action. We were also looking to reduce weight, and the new frame helped a lot—it’s over 4 pounds lighter than the 300 frame.
The frame isn’t the only thing that’s lighter on the 2018 bike, right? The specs show it weighing some 17 pounds less than the 300. What other parts lost weight?
We looked at everything in an effort to minimize weight. The wheels have a new shape, and they’re about 600 grams lighter. The fairing brackets were all made lighter, and even though the exhaust is Euro 4, it’s lighter because we went with thinner 0.8mm tubing. The clutch is even lighter—we reduced the diameter by about 12mm so it’s more compact.
Some of the more subtle changes with the bike include switching providers for things like the suspension and brakes. Was the change from Tokico calipers to Nissin parts strictly economics, or was there a performance reason?
We’ve always sourced parts from both manufacturers, but we switched to Nissin for performance reasons. The Nissin caliper is more rigid, and that’s important for performance since this bike is capable of higher speeds and has a larger brake rotor. The caliper has to handle more stress. We also changed the brake hoses. The goal was to get more predictable brake feel for newer riders. We didn’t design the brakes for the track, they’re supposed to be good for the street.
Everyone seems to love the sound and feel of a 270-degree crank like the setup Yamaha uses on the FZ-07. Did you consider changing the crank layout from 180 degrees to 270 for the 400 to give it more character?
The twisted crank does sound and feel different and has more punch down low, but the 180 has better revving and that characteristic was important for a Ninja. The bike had to have a “Ninja” feel. The 180 crank revs higher and the engine is more exciting at higher rpm. The 270 crank is also more expensive to make, and keeping the Ninja’s price low was a concern.
If there was one area where you would have liked to have made more improvements or modifications, what would it be?
Ahh [thinking]. I would have liked to have done better with the front suspension. Adding adjustments like preload and damping, that would help the bike’s performance a lot. Maybe next year!