The moment that Kawasaki will launch the ZX-4R is getting closer. Just before Christmas last year, Team Green registered the ZX400SP model year 2023 with the California Air Resources Board, suggesting that the engine will be put on the market this year.
It has been rumored for some time that Kawasaki is working hard to revive the ZXR400, which was launched in 1989, but was already taken out of production in 1999.
The rumor spread soon after Kawasaki launched the four-cylinder ZX-25R for the Asian market, which took off after the generally well-informed Japanese magazine Young Machine reported that Kawasaki had a ZX-4R in the pipeline.
After the publication of Young Machine, we were also convinced, but the only question that remained was whether it would only be intended for the Asian market, or whether the engine would also be marketed in other continents.
Six months ago the answer came from the NHTSA (National Highway Traffic Safety Administration) of the United States, where two new Kawasaki models were listed in the VIN decoder: ZX400SP and ZX400PP, both registered as Super Sports models. It was further guessing about the specs of the block, which were still to be determined.
The next step Kawasaki has now taken is registration with the California Air Resources Board, although that only applies to the ZX400SP model. However, what we can now say with 100% certainty is that it is a 399cc four-cylinder with a six-speed gearbox, model year 2023 from the PKAXC.399AAC engine family.
The CARB data also tells us that the 399cc four-cylinder only emits 0.1 gram/km HC(hydrocarbon)+NOx and 0.4 gram/km CO (carbon monoxide), which is significantly less than the current 399cc parallel twin, which according to CARB data 0.3 gram/km HC+NOx and 4 gram/km CO emissions.
Remarkable figures, especially because the 399cc four-cylinder is expected to deliver much more power than is now squeezed out of the twin. When you consider that almost 220 horsepower can be obtained from a one-litre superbike nowadays, 80 horsepower from a four hundred should really be achievable. We have heard from a reliable source that it makes more than 17,000 rpm.
That a ZX-4R is coming has now become even clearer, the only question (outside the specs) remains when it will be put on the market. On the Kawasaki USA website you can read that two new models will be announced on February 1. Those could be the two EV models announced at EICMA in Milan, but we wouldn’t be surprised if one of those two will be the ZX-4R.
– Thanks for information from Motorfreaks.