determined point , bringing a much more aggressive cam lobe into contact with the intake valves . That lobe increases the lift , duration and overlap to maximise the amount of fuel and air that can get into the cylinder , ensuring the engine makes as much power as possible . ShiftCam moves the camshaft by using a solenoid to insert a peg into a spiral groove on the camshaft . When engaged , the turning movement of the camshaft also moves it sideways , and the design means it can only switch lobes when the intake valves are closed and the cam lobes aren ' t applying pressure to them . To move back to the low-rpm lobe , another solenoid and peg are engaged in a reversed version of the spiral groove , pulling the camshaft back again . In the S1000RR ' s fourcylinder engine , a slightly more complex version is needed to allow the lobes for different cylinders to be shifted separately . Although a single-cylinder engine could use the same version of ShiftCam that ' s employed on each cylinder of the R1250 boxer twin , BMW ' s new patent shows a more compact version of the idea . The solenoids and the spiral grooves are positioned between the two intake valves , rather than at the end of the camshaft , to allow the engine to be narrower overall , and as a result the spark plug needs to be moved and mounted at an angle to make space for the ShiftCam actuators .

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 . 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 multicylinder 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 largercapacity development of the existing ZX-25R 250 cc fourcylinder 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 .