The Strongest 400cc in History | 61ps over is in Sight! Kawasaki’s Direct 4SS ZX-4R will Debut Next Year

Written: Best Car Web Editorial Department, CG/SRD
*This article was originally published in "Best Car Web on August 17, 2022.

With the CB400SF/SB out of production, the 4-cylinder disappears from 400cc. However, Kawasaki appears to be introducing a new straight-four, the Ninja ZX-4R　 A supersport with the strongest power ever in its class and as light as a 250 is about to be born.

According to the U.S. identification number, a 2023 release is a definite prospect.
Can we expect the price to be around 1 million yen (approx. 7225 USD)?

400cc version of the ZX-25R debuts to replace the fading straight-4 CB400SF.

As previously reported, Honda has announced that the CB400 Super Fore/Super Boldor will cease production at the end of October 2022. Riders were shocked to learn that the world's only 400cc inline 4-cylinder model would disappear.

Meanwhile, there are rumors that Kawasaki will introduce a new straight-4 model in the 400cc class. That is, the Ninja ZX-4R, based on the Ninja ZX-25R, the only straight-4 in the current 250cc class, will be powered by a 400cc straight-4.

Kawasaki is currently offering the two-cylinder Ninja 400 in the 400cc class. Based on the Ninja 250 chassis, the Ninja 400 is lightweight and high-powered, and has been the top-selling 400cc model for three consecutive years since its debut year in 2018.

Furthermore, by adding the four-cylinder ZX-4R to this class, Kawasaki will have a one-of-a-kind four-cylinder in the 400 class, following the 250 class. This would truly establish a solid lineup.

Based on the Ninja ZX-25R, the Ninja ZX-4R is rumored to debut with a 400cc straight-4 (above is a projected CG).
Expect a color scheme that respects the original ZXR400.

New Generation Straight-4 Reaches 60ps Range Surpassing the GSR400?

The base ZX-25R would feature a lightweight & rigid tubular steel diamond frame and an inverted fork body.
The ZX-4R would mount a 400cc straight-4 on it. The two-cylinder Ninja 400 was a lightweight, high-power 400cc engine mounted on the bodywork of its little brother, the Ninja 250, and the ZX-4R is expected to follow the same approach.

It is unclear whether the straight-4 unit will be a souped-up ZX-25R or a completely new design. However, maximum output is expected to exceed the 60ps mark.

In the 400cc class of successive generations of domestic-spec models, the Suzuki GSR400's 61 hp is the most powerful ever. Following the elimination of voluntary horsepower regulations in Japan in 2008, the 2009 model change boasted 61 hp.

The ZX-4R is expected not only to surpass the current CB400SF's 56ps, but also to surpass the GSR400. When the GSR was launched, the emission regulations were the 2006 regulations (equivalent to Euro 3), which are less stringent than today's regulations. It would be a great accomplishment if the ZX-4R could surpass 60ps while complying with the stricter emission regulations.

The Ninja ZX-25R debuted in 2020. The newly designed straight-four engine has an ultra-high red zone of 17,000 rpm and beyond, and produces 46 hp.

Focused reinforcement of suspension with W-discs, wider tires, etc.

The exterior design of the ZX-4R seems to be the same as that of its little brother, the ZX-25R. However, the suspension is said to be strengthened along with the increased power.

First, the front brake is a double disc compared to the ZX-25R's single disc for increased stopping power.
The tires are also expected to be wider. The ZX-25R's front tires are 110/70R17, while the rear tires are 150/60R17.
It is possible that the tires will be 120/70ZR17 at the front and 160/60ZR17 at the rear, similar to those on the Ninja 650, which has 68 hp and similar horsepower.

The information is that the exhaust system will be a separate silencer type. The ZX-25R had a very short down exhaust system, but will it use a Ninja 400 or ZX-6R style different section silencer?

Electronic controls such as the two-stage power mode, three-pattern traction control, and ABS will follow the ZX-25R.
In any case, it will be worthy of the name of the strongest 400cc supersport.

The ZX-25R has a single disc. The left side of the wheel has a boss where the disc could be originally installed.
The ZX-4R uses this wheel and converts it to a W disc.

Identification code for the 2023 "400cc 4-cylinder" model is already registered in the U.S.

There is also strong evidence supporting a 2023 launch.

According to MOTORCYCLE.COM, a major U.S. motorcycle media outlet, as of March 22, the NHTSA (National Highway Traffic Safety Administration, U.S. Department of Transportation) released a list of Kawasaki vehicle identification number = VIN decoders. Two codes, ZX400PP and ZX400SP, reminiscent of the ZX-4R, were added to this list.

The leading ZX stands for a high-performance sportbike, as in ZX-10R (ZXT02), ZX-6R (ZX636), and so on. The 400 is the approximate displacement, and the letters that follow indicate variant models. In other words, just as the ZX-25R has a standard model and an advanced SE version equipped with a quick shifter, the ZX-4R will probably have two grades.

And the P at the end indicates the 2023 model year. Although the name Ninja ZX-4R does not appear in the VIN decoder, there seems to be no doubt about its existence and year of release.

In addition, the list will also indicate the engine displacement, number of strokes, number of cylinders, and engine power (kW). According to this, the ZX400PP and ZX400SP have 4 cylinders and TBD engine power (to be determined).

Incidentally, the code for the 2023 Ninja 400 is EX400GP for the ABS version and EX400HP for the non-ABS version.
This model has two cylinders and maximum output of 36 kW (48.9 ps), matching that of the current model.

ZX400PP and ZX400SP appear to be ZX-4R. P means the 2023 model year, and the five numbers from the right are displacement. The five numbers from the right indicate displacement, followed by the number of strokes, number of cylinders, and power output. The list is from MOTORCYCLE.COM.

Patent reveals that the ZX-25R was designed to be 400cc in the first place.

Yet another patent exists that suggests a 400cc four-cylinder.

According to patent information published in March 2021, Kawasaki applied for a patent in October 2019 for a cooling structure to control engine temperature rise. The drawing in the application shows a ZX-25R side cowl that efficiently cools the engine by introducing running air through air ducts.

And the patent states, for example, that the invention can be used even more suitably for a 4-cylinder 400cc engine.
Although the cowl was actually used on the 250cc ZX-25R, the ZX-25R may have originally been designed with the 400cc version in mind.

Drawing of the patent that Kawasaki filed in Japan in 2019. The design is said to be suitable for a 4-cylinder 400cc engine, but the face and side ducts are similar to those on the ZX-25R

Price is about +70,000 yen (approx. 510 USD) from ZX-25RI would be happy if it is under 1,000,000 yen (approx. 7220 USD)

If the ZX-4R is to be launched in 2023, will it be announced at the EICMA (Milan Show) in the fall of 2022?
After that, following its launch in the U.S., it should of course be introduced in Japan.

We also expect it to be priced at a reasonable level. The ZX-25R is currently only sold in Indonesia, Japan, and other parts of Asia, but the ZX-4R will be a global model sold in North America, Europe, and other regions. Therefore, cost reductions due to economies of scale can be expected.

The current ZX-25R SE with a quickshifter costs 935,000 yen (approx. 6750 USD) [847,000 yen (approx. 6115 USD) for STD]. The price difference between the two-cylinder Ninja 250 and 400 is 71,500 yen. Based on this simple calculation, the SE version of the ZX-4R will cost 1,000,000 yen +/- and the STD will cost less than 1,000,000 yen (approx.7220 USD), but we would be happy if it were even cheaper!

The Ninja ZX-4R is the only 4-cylinder model in its class, and if it is the most powerful Yonhak ever, it will be the talk of the town. And if the price is not too different from that of the ZX-25R, it is sure to be a hit. We can hardly wait for the official announcement, which is expected this fall.

Original Source [ Best Car Web ]