We’ve been overlaying the Kawasaki Ninja ZX-4R for some time now, and even up till it was revealed this week, there was skepticism about whether or not the little four-banger would truly come to America.
After the official announcement, the plain questions got here up: How a lot does it price? How a lot does it weigh? And the way a lot horsepower does it produce? Kawasaki answered the primary two, with the 2023 Ninja ZX-4RR priced at $9,699 with a claimed curb weight of 414.5 kilos. Kawasaki USA was much less forthcoming in regards to the energy output, solely describing “a really linear energy supply that gives nice street-going
efficiency at decrease engine speeds whereas excelling because the revs climb to its over-15,000 rpm redline.”
It’s commonplace for the American subsidiaries of motorbike producers to omit efficiency figures, however luckily, their Worldwide counterparts are usually extra forthcoming. Kawasaki Europe’s announcement, revealed the Ninja ZX-4RR (plus the ZX-4R variant that isn’t being provided within the U.S.) will make 57 kW (76.4 hp) from the 399cc 16-valve Inline-4, and 59 kW (79.1 hp) with ram air. These figures do include some asterisks, nevertheless, because the European press launch notes specs could also be topic to vary and should fluctuate from market to market.
In the meantime, Australian certification information has the ZX-4 fashions producing 55 kW (73.8 hp), and in contrast to Kawasaki Europe, it additionally cites the engine pace that produces that peak: 14,500 rpm.
So, in worldwide markets, you possibly can count on to get one thing within the mid-to-high 70s for horsepower from the ZX-4R. However in case you’re within the U.S., it’s possible you’ll have to mood your expectations.
Bike.com has obtained car identification quantity data submitted by Kawasaki to the Nationwide Freeway Visitors Security Administration has the ZX-4RR (listed below its mannequin code of ZX400SP) as producing simply 42 kW, or 56.3 hp. Whether or not that’s with or with out ram air issues little, as potential American clients could also be disenchanted to know the ZX-4RR is down greater than 25% from the European spec. Or, to place it one other manner, the ZX-4RR claims much less energy than the Vulcan S.
Certain, the Vulcan’s received 250cc over the ZX-4RR, however clients count on extra from a four-cylinder Ninja, particularly one with a double-R designation. So, what provides?
The probably offender is a decrease rev restrict. Kawasaki Canada notes on its official web site that the ZX-4R and ZX-4RR “have a most RPM of 11,500 rpm in Canada as a result of noise laws.” These laws state a most quantity between 78 dBA and 83 dBA, relying on the testing methodology.
Laws in America fluctuate by the state, however many fall someplace inside that vary for bikes travelling at speeds sooner than 35 mph. This leads us to consider that the U.S.-spec Ninja ZX-4RR additionally has a most engine pace restricted effectively under the 16,000 rpm indicated on the issued press photographs (which be aware they’re for European spec fashions), but in addition under the “over-15,000 rpm redline” Kawasaki USA claims in its supplies.
We reached out to Kawasaki USA in regards to the Ninja’s rev restrict and have been advised they have been awaiting remaining affirmation on specs from Japan. So, like their European counterparts say, specs should be topic to vary. We’ll present an replace when Kawasaki USA has extra to inform us.
An precise restrict inside the 11,000 to 12,000 rpm vary is about 75% of the “over-15,000 rpm” claimed redline, which can be sufficient to choke the U.S.-spec Ninja ZX-4RR right down to a 56.3 hp output from the European figures.
As Troy famous with Kawasaki’s announcement, the ZX-4RR KRT is just $1,000 lower than the ZX-6R, making it arduous for some clients to lean in the direction of the smaller bike. If there’s a rev restrict on the ZX-4RR, that might neuter certainly one of its main appeals, the sound of 4 small pistons pounding at a particularly excessive engine pace.
After all, ECU tuners could possibly unlock extra energy from the ZX-4RR, serving to it attain extra of its potential. However which means spending just a little bit extra money on high of the ZX-4RR’s $9,699 MSRP.
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