Kawasaki ZX-4R revives the tiny four-cylinder By Ben Purvis
Japan's motorcycle industry reached its position as the unchallenged masters of technology via an amazing ability to miniaturise. Whether you think of the six-cylinder Honda GP bikes of the 60s or the 'bubble era' production machines of the late 80s, they share a common trait - engines that trade capacity for more cylinders and higher revs in the pursuit of power.
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After peaking at the end of the 1980s, when every Japanese brand offered 250 cc and 400 cc four-cylinder, four-stroke sports bikes, the trend for small multi-cylinder machines has receded. Now, thanks largely to Euro 5 emissions limits, even the 600 cc four-cylinder sports bikes that have been a Japanese calling card since the 80s have all but disappeared from the market. Euro 5's harsh limits on unburnt hydrocarbon emissions are largely to blame, favouring larger-capacity, lower-revving engines over screaming, small four-cylinder designs. That's why we've seen an explosion in the number of 600 cc-800 cc parallel twins, and why the launch of Kawasaki's new ZX-4R is all the more remarkable.
Although the ZX-4R has long been an open secret, a larger-capacity development of the existing ZX-25R 250 cc four-cylinder that's sold in Asian markets, few believed that the bike would be offered worldwide. However, on its unveiling, Kawasaki revealed that the ZX-4R is going on sale not only in Asia but also the USA, and that it will come to Europe as a 2024 model.
With the ability to rev to around 16,000 rpm and an astounding peak power of 57 kW (76.4 hp), the ZX-4R punches much harder than even the best 400 cc fours of the 1990s, although in some markets it is impacted by rpm limits to meet local emissions rules. In the USA, for instance, the bike sadly loses around 20 hp, with a peak of 42 kW (56.3 hp) and just 11,500 rpm. European bikes are, however, expected to be full-power machines when they arrive in late 2023.
Unlike the old 400 cc fours of the 80s and 90s, the ZX-4R is fuel injected and uses ride-by-wire, allowing four riding modes - Sport, Road, Rain and Rider-Adjustable - each with a different map for the power output and traction control. Three versions of the bike will be offered: the base ZX-4R, the ZX-4R SE and ZX-4RR. The two higher-spec models get an up/down quickshifter as standard, plus upgraded Showa SFF-BP forks, while the top 'RR' version also gains a fully adjustable Showa BFRC-lite rear shock.
The chassis is essentially identical to the smaller ZX-25R, with slight tweaks to the rake and trail, and the ZX-4R manages to weigh an impressively slender 188 kg, including 15 litres of fuel in its tank (189 kg for the SE version, which has extra kit including a different screen, frame sliders and a USB socket). All versions get a TFT dash with phone connectivity and a dedicated 'track' mode among the display options.
