Kawasaki Z900Rs
‘It seems that plenty of people at Kawasaki are in touch with their firm’s past glories, because just a year after the Z900’s arrival it is now joined in the range by the Z900RS. The RS initials stand for Retro Sport’. We just came back from a first ride
modern four-cylinder and mechanicals under classic and very desirable old-school skin
Kawasaki seemed to be turning down an obvious opportunity while launching the new-generation Z900 a year ago. It was a powerful 948-cc four with a tubular steel frame and aggressive, modern styling. It was quick, sweethandling and a blast to ride. Surely the name Z900, echoing that of the mighty DOHC four that was one of the greatest superbikes of the 1970s, presented a perfect chance to add some Kawasaki heritage to the mix?
It seems that plenty of people at Kawasaki agreed and are in touch with their firm’s past glories, after all, because just a year after the Z900’s arrival it is now joined in the range by the Z900RS. The ‘RS’ initials stand for ‘Retro Sport’, and the new bike’s round headlight, chrome-rimmed clocks, teardrop tank and duck-tail rear end bring to mind the original Z900 and its all-conquering Z1 predecessor.
The naked RS is a stylish, dynamic, entertaining machine that does a fine job of blending the look of Kawasaki’s 1970s superstars with modern performance
The RS doesn’t outperform every other bike on the road, as the Z1 did on its launch in 1973 (Kawasaki might argue they’ve got that base covered with the ZX-10RR), but it’s a worthy successor. With 111 PS and a kerb weight of 215 kg, it has a much better power-to-weight ratio than the old 903-cc fourcylinder warrior, as well as having a vastly superior chassis and modern electronics.
Kawasaki’s engineers have put this last year to good use, too, because the RS is far more than simply a Z900 with a few cosmetic modifications. Having decided that a retro four would appeal to a slightly different type of rider, they retuned the engine to give more mid-range performance at the expense of top-end, while also redesigning the frame, uprating the front brake and adding LED lighting and traction control.
The liquid-cooled engine retains its 948-cc capacity and DOHC, 16-valve layout but is reworked with new camshafts, reduced compression ratio and a 12 per cent heavier crankshaft. The new, double-skinned four-into-one exhaust has narrower downpipes than the Z900’s system, which also helps boost mid-range output. Maximum torque remains almost unchanged but it’s produced 1,200 rpm earlier, at 6,500 rpm, while peak power is down by 14 PS.
Most chassis changes are also intended to make the RS more rider-friendly than the hardcore Z900. New triple clamps give five mm less trail, for lighter steering, which compensates for the fact that rake is increased by half a degree, to 25 degrees, and the wheelbase is 20 mm longer. The top yoke is also raised by 40 mm, which along with the one-piece handlebar puts the rider’s hands higher, wider and further back for a more relaxed riding position, in conjunction with foot-rests that are 20 mm lower and further forward.
Frame changes include narrower top tubes, allowing a slimmer fuel tank. The lower rear sub-frame leaves room for a thicker, retro-style dual-seat. Other chassis changes include new thin-spoke 17-inch wheels, designed to resemble wirespokers (with the advantage of being lighter) and new fourpiston monobloc front brake calipers. Forks are multiadjustable 41-mm diameter USD units and the rear suspension is a near-horizontal, rising-rate shock that is adjustable for preload and rebound damping.
Chief Project Designer Norikazu Matsumura made sure there were plenty of styling cues from the Z1. Period shapes include not only the tank and duck-tail but also the side-panel area. The launch bikes’ paint design and Candy orange and brown colours come straight from 1973; alternatives are black or matte green.
The detailing gets better the closer you look, and the more familiar you are with old Zeds. It takes in the camshaft end caps, side-panel badges’ lettering and finish, round mirrors, seat stitching, and the way the oval rear light’s LEDs glow like the original bulb. Even the instruments’ typeface matches that of the old dials. However, between the chrome rims is a modern digital display incorporating fuel-gauge, consumption reading, gear indicator, and clock.
Apparently, this is the first Kawasaki whose exhaust note has been deliberately tuned for sound. The effort was worthwhile because the RS fired up with a throaty rasp that can’t quite match the original four-pipe rumble but is tuneful by Euro 4 standards. When I let out the lever of the light slipper clutch, the bike pulled forward easily, its lower first gear compensating for the fact that overall gearing has been raised, as has sixth to give a more laid-back cruising feel.
Maximum power might be slightly down on the Z900, but the RS still has plenty up top for a naked bike, and its flexibility was very welcome. The graphs show there’s more torque everywhere below about 7,000 rpm, giving the new bike a pleasantly old-school urgency from 3,000 rpm or below — and a seriously arm-yanking burst of acceleration from about five grand onwards, as it headed for a top speed that would approach 225 km/h if given enough room.
I didn’t get near that on a cold day in northern Spain, but the Z900RS felt smooth and fairly effortless on a brief motorway blast despite the inevitable wind-blast. And it was more at home when we turned off on to twisty roads in the hills north of Sitges, though there was no missing the throttle’s slightly abrupt response from closed. The jerky delivery is not as noticeable as with bikes including Suzuki’s GSX-S1000 or Yamaha’s original MT-09, but detracted slightly from the bike’s poise and pace, especially when exiting slow turns.
Chassis performance was very good, especially for a bike that has been designed for gentle use as well as back-road scratching. The Kawasaki steered with a neutral and enjoyably light feel, helped by the considerable leverage available via those wide bars. Suspension is respectably firm yet compliant, its travel unchanged from the Z900’s (at 120 mm front and 140 mm rear). Both ends were sufficiently well controlled to make the bike quick and fun without the need to fiddle with the adjusters.
Those new monobloc front calipers meant there was plenty of stopping power, too, in combination with a radial master cylinder and discs that are round and drilled, rather than having the Z900’s petal shape. Ground clearance was very adequate, though the side-stand bracket eventually scrapes when you’re pushing towards the grip limits of the Dunlop D300 tyres. There’s an adjustable traction control system which allows wheelies in the sportier of its two settings — a feature the original Z900 definitely didn’t have or need.
The Kawasaki showed plenty of promise as an all-rounder, too, when we headed into central Barcelona the next day. Despite hard use it averaged about 6.0 litres/100 km, giving a range of roughly 250 km from the 17-litre tank. Its wide bars, generous steering lock and respectably light weight combined to make it manoeuvrable in traffic. And although the seat is not especially low, at 835 mm, it’s slim enough that most riders will be able to get both feet down.
For those with short legs there’s a 35-mm lower accessory seat to help. Other extras include an authentic looking chromed pillion grab-rail, a tinted fly-screen and alternative tank badges, as well as more practical bits such as heated grips and centrestand. Alternatively, if you fancy a racier ride, there’s the Z900RS Café that features a bikini fairing, lower bars, cutdown dual-seat, brushed steel silencer, and paintwork in Kawasaki lime green and white.
That looks good and the naked RS is a stylish, dynamic, entertaining machine that does a fine job of blending the look of Kawasaki’s 1970s superstars with modern performance and an appealing character. It’s a far better bike than the forgettable Zephyrs of the early ‘90s and is a worthy rival for retro-models, including BMW’s R nineT and Yamaha’s XSR900.
Perhaps, the only real drawback is that the RS is considerably more expensive than the Z900, but even so it might well prove more popular. Kawasaki waited for four decades to revive the Z900 name. The extra year that they took to create the Z900RS looks like time well spent.