2022 Bimota KB4 Road Test: SuperTourer!

Kawasaki’s November 2019 acquisition of a 49.9% shareholding in Bimota has brought the Italian boutique manufacturer back from oblivion, to the point that despite a slowdown caused by component supply issues, it’s now constructed all 250 examples of the its limited edition kickoff model unveiled at the 2020 EICMA Milan Show, the supercharged hub-centre Tesi H2 now being shipped to its dealers around the world – but mainly in Japan. As Bimota’s strapline for the bike succinctly puts it – “The Revolution Continues!”

The Tesi H2 has now been joined by the KB4, a less obviously radical but nonetheless innovative follow-up model, which having previously been shown as a concept bike at EICMA 2020, was displayed in production-ready guise at last November’s show, with a retail price in Japan of 4,378,000 yen including 10% tax (3,980,000 + 10% tax 398,000) which is currently 31,200 euro, or 28,400 euro tax free. But there’s still no word of a European price, nor of availability despite production being in full flow in Bimota’s new 2,500m² factory in the born again company’s Rimini birthplace housing its 13 employees. With 105 examples already manufactured at the time of my recent visit there, and 30 of the bikes already shipped to Japan, I was honored to be the first journalist anywhere in the world to be able to ride the result. Despite having tested almost all the different motorcycles Bimota has produced in its half-century of existence – it’ll be celebrating its 50th birthday next year – and even raced some of them, after a full 215km/135mi day of riding the KB4 on the challenging roads of the hilly hinterland behind Bimota’s Rimini factory, I was surprised to discover this wasn’t at all the bike I thought it was going to be, after seeing it make its debut at last year’s Milan Show.

That’s because the KB4’s slinky styling by Bimota’s in-house progettista Enrico Borghesan makes it appear to be the latest of the many Bimota Superbikes-for-the street concocted down the years by Bimota’s COO & CTO Pierluigi Marconi, 62, and his predecessors. But it’s not. “If we’d wanted to make a new generation Bimota Superbike, we couldn’t have avoided using Kawasaki’s ZX-10RR engine to do so,” says Marconi. “But quite apart from the difficulty of improving on a motorcycle that’s won seven World Superbike titles in the past ten years, that wasn’t what I or Kawasaki wanted to do. Instead, we’ve used the 1043cc motor from the Z1000SX Ninja, because our objective is to provide our customers with the ultimate real-world motorcycle, a sports tourer – no, SuperTourer! – which is the best handling bike on the market in everyday use, while also rational and user-friendly to ride. Please tell me if we succeeded!”

Before heading off for the hills to try to determine that, a close look at one of the unclothed bikes being assembled by Bimota’s four-man production team showed the nowadays radical format Marconi has opted for. This sees the Z1000SX’s liquid-cooled 77 x 56 mm 16-valve four-cylinder in-line motor with offset chain drive to the twin overhead cams positioned way forward in the wheelbase compared to the Ninja it’s borrowed from, to deliver a pretty extreme 54/46% forward weight bias that’ll help glue the front tire to the ground in turns, only partially further aided by the rider’s own personal kilos thanks to a more upright riding position. “The concept for the KB4 is for it to be like a 600 with a 1000cc engine,” says Marconi. “We’ve made a really short bike with a 1390mm wheelbase, and we have a lot of weight in front thanks to mounting the engine further forward, which was made possible by putting the radiator at the back, under the seat.”

That’s a format Marconi is already familiar from his time at Benelli 20 years ago, where the Adrian Morton-designed Tornado and TnT 900 Triples he was in charge of developing both featured a rear-mounted radiator with twin extraction fans beneath the rear part of the seat. It was a format already pioneered on the Britten V-1000 Twin, as well as the Saxon Triumph 900 triple which I used to race in the BEARS World Series – indeed, I can recall Marconi’s men taking lots of photos of it during the 1995 Italian round at Monza, when I ahem, beat the Britten for the win on the British triple. The benefit was the same as on the KB4 – a more forward weight bias that proved beneficial in keeping up turn speed, albeit without a radiator fan on the racebikes which meant that I and the Britten riders had to be sure to be last back to the grid after the warmup lap, to avoid overheating while stationary waiting for the start!

On the Bimota KB4 that’s been addressed via the installation of a pretty loud extraction fan which kicks in when the coolant temp reaches 100°C, to run it down to 95°C when it cuts out. Borghesan’s styling incorporates two large cooling ducts running the length of the bike from either side of the fork legs to the radiator, with two more ducts under the single round headlight feeding the Kawasaki airbox. Indeed, the entire stock Z1000SX mechanical and electronics package has been transplanted to the Bimota, thus not only cutting back on time and cost which would otherwise have been spent concocting a dedicated KB4 one, but also delivering the same well-proven array of riding aids and engine performance that the 1000SX Ninja offers.

So, the KB4’s 1043cc Euro 5-compliant motor featuring an 11.8:1 compression ratio delivers 142bhp/105kW at 10,000 rpm, same as the Ninja SX – albeit some way short of the 200bhp/150kW at 13,200 rpm of the more potent 998cc ZX-10R – with peak torque of 111Nm/81.87 ft-lb on tap at 8,000 revs. But this already more user-friendly horsepower is delivered via two power modes: Full, which is as per the label, and Low, which has a softer delivery with output limited to 105bhp/78kW, just 75% of Full. These are paired to four different riding modes – Sport, Road, Rain, and a customisable Rider setting – with three different settings for TC/traction control.

The Ninja’s colour TFT dash has also been transplanted to the Bimota, as well as its two-way quickshifter and cruise control. Mmm – factory-supplied Japanese mechanical and electronic quality on a hand-built Italian motorcycle, is a pretty appealing combo.

One that’s made even better by the exquisite build quality and high end componentry of the KB4, with its composite chassis consisting of an upper main trellis frame in chrome-moly steel tubing, mated to twin billet-machined aluminum engine plates, with the engine itself as a fully-stressed chassis component. A fully adjustable 43mm Öhlins FG R&T NIX30 upside down fork offering 130mm (5.1 in.) of travel for the OZ forged aluminum 3.50-in. wheel is carried at a 24° rake with 100.8mm of trail – super-rational steering geometry compared to Bimota’s often more extreme numbers on its racers-with-lights. And yet thanks to having the wide radiator relocated to beneath the seat, the 30° steering lock of the KB4 is exceptionally tight by sportbike standards, making feet-up U-turns in narrow roads perfectly feasible. Amazing!

At the rear, there’s a three-piece aluminum swingarm machined from separate billets of Anticorodal aircraft alloy operating a fully-adjustable Öhlins TTX36 shock via a progressive-rate link. This delivers just 122mm (4.8 in.) of travel for the 6.00in forged OZ wheel, which carries a 190/50ZR17 Pirelli Diablo Supercorsa Evo, with a 120/70ZR17 front. Wheelbase is indeed the ultra-short (for a one-litre four) 1390mm Marconi spoke of. The bodywork is all carbon fiber, resulting in a low dry weight of 189kg with all street equipment. That’s stopped via a Brembo brake package consisting of twin 320mm floating front discs – downsized from the 330mm items on the Tesi H2 – gripped by radially-mounted Monoblock four-pot calipers, with a single 220mm rear disc and twin-piston caliper. Kawasaki’s own dual-channel ABS has been adapted to the Bimota, just as on the Tesi. Eccentric adjusters on the rear suspension allow ride height to be easily changed.

Just sitting aboard the new Bimota’s rather incongruous-looking tan leather seat pad tells you at once this bike isn’t what it seemed it would be. Thanks to the quite low 810mm (31.9 in.) seat height by sportbike standards (adjustable over a 16mm (0.6 in.) range) you sit within the KB4 rather than on it, with a relatively upright riding stance, thanks partly to the quite wide-spread clipon ‘bars, which aren’t as steeply dropped as on some other Bimota models. So, being higher-set are less stressful on your wrists. Coupled with surprisingly low-set footrests adjustable via eccentrics over a 30mm (1.2 in.) range – I used the middle setting, which didn’t, however, drag them even with the grippy Pirelli rubber – this delivers a riding position which, while not exactly relaxing, is certainly more rational (that word again) and accommodating than on almost any other Bimota I’ve ever ridden. Let’s not forget that this is the company which invented the modern-day sportbike back in 1987 with the YB4 EI, the world’s first ever aluminum deltabox beam-framed motorcycle with electronic fuel injection. Successive Bimota fours have all followed in the tire tracks of that design – until now. While not exactly a BMW R1250GS go-anywhere workhorse, the KB4 is definitely a less extreme, better-rounded Bimota, that’s more easy-going and less demanding to ride than its ancestors.

Which is not to say it’s devoid of Bimota’s traditional qualities of handling and performance, and didn’t like to carve corners in the junior Appenines that my ride with Pierluigi Marconi – he on the prototype KB4 RC Naked version – took me to, especially once we found some smooth stretches of twisting tarmac that hadn’t been attacked by frosts anytime over the past decade, and remained unrepaired like so many Italian roads. That’s where the extra front end grip from the KB4’s forward weight bias made itself felt, allowing greater turn speed even if I wasn’t able to physically help out too much in achieving this. That’s because the shape of the 19.5-liter (5.2-gallon) fuel tank sitting behind the airbox doesn’t allow you to crouch forward under the screen, because your chest hits its upper rear section before you’ve leant forward very far.

“It’s true, we’ve not been able to package the fuel as well as I’d have liked,” admits Marconi, “but we’ve achieved a satisfactory front end weight bias mechanically, without the rider needing to add to this. So, this is a bike that you don’t need to move about on very much when you ride it – just relax, and go with the flow!” Indeed, that semi-upright stance was quite comfortable for a 180cm/5’10” rider like myself even at high speed, thanks to the way the original Kawasaki SX screen that’s been retained on Borghesan’s bodywork is subtly shaped to deflect most of the wind blast up onto the upper part of my helmet, when leaning as far forward as the fuel tank would let me. Still, I’d like to have seen some of that touring-level fuel capacity sacrificed to deliver a slightly lower and better-rounded shape to the rear of the KB4’s fuel tank.

Another element in the KB4’s relaxing ride was the nature of the power delivery of the Z1000SX Ninja motor, which while more than adequately potent was also reassuringly flexible, with heaps of midrange power, and an ultra-flat torque curve. There’s a slight surge in acceleration after 6,500 rpm, but the power delivery doesn’t feel at all peaky or layered. This meant I didn’t need to use the perfectly set up two-way quickshifter unduly often, because the engine came on strong from as low as 3,000 rpm upwards, building power in otherwise linear fashion all the way to the 11,800 rpm rev limiter, if I really wanted it to. Which I didn’t – well, except just the once to say hello to the soft-action cutout: instead, I usually short-shifted at 7,500 rpm in every gear after surfing the meaty torque curve that peaked 500 revs higher, and always found the Bimota ready to pull hard and strong in the next higher ratio. On some twisty sections I’d hold third gear for ages on end, running as low as 40 kmh/25 mph in hairpins before rocketing down the following straight to the next tight turn with the engine eager to run into the five-figure zone to save a couple of gearshifts, if I wanted. Thanks to the KB4’s light weight, acceleration was downright impressive. While on faster deserted stretches once the road opened up, the Bimota would cruise perfectly happily at 100 mph/160kmh with the engine pulling a mere 7,500 revs, and despite the upright stance, I wasn’t blown about unduly, thanks to the surprisingly effective deflector screen.

But it’s by its handling that any Bimota will ultimately be judged, and on the KB4, this was immediately as confidence inspiring as I believe all Marconi’s conventional (i.e. non-Tesi) Bimota designs always have been – this is a designer who knows how to find the sweet spot in making a motorcycle steer and handle, no matter what engine he’s wrapped the frame around. Besides the KB4’s light weight and the flickability, this delivers, that’s thanks in no small part to Bimota test rider Gianluca Galasso, who’s worked with Marconi in optimising his chassis settings and dynamic set-ups for most of the past 35 years, and here GG has performed his usual task to best effect.

The ride quality and compliance of the KB4’s Öhlins suspension was outstanding, in my opinion better than any previous Bimota I can remember riding. It holds a line extremely well once cranked over at speed, yet changes direction easily – it’s light-steering without being nervous. I could trail brake deep into the apex of a turn with the fork soaking up any road rash I’d encounter, despite the inevitable weight transfer from using those fabulous brakes to something approaching their full potential and trailing them into the turn. Hooking up the rear Pirelli on the exit was almost always effective, even if there were ripples and some lumps and bumps to be traversed – it’d be rare that the road surface was so bad that the Bimota jumped or skipped about when running over it, rather than have the suspension soak it up, despite the surprisingly small 122mm (4.8 in.) of rear wheel travel. Later on, following Gianluca on his suspension test track aka the back roads of the Republic of San Marino overlooking Rimini had the KB4’s front end juddering over downhill corrugated surfaces – but without ever being overcome by such extreme poor road quality.

So what? This is a sportbike, isn’t it – so horses for courses means a Bimota isn’t expected to have to cope this this kind of extreme road surface. But this one is – and does – because it’s been designed to go places and do things that nothing else to have emanated from the Rimini manufacturer ever did before – well, barring the short-lived DBX Street Enduro. This is a very happy marriage of the Kawasaki Z1000SX motor and the Bimota composite frame, whose bodywork combines recalling the classic shapes of the iconic Bimota models of the ’70s and ’80s, with the function and utility of a modern motorcycle. “The KB4 looks sleek and fast – just like the process that created it!” says designer Enrico Borghesan. “It went from first sketch to full-size model in a very few months using computer-aided design – and without missing any of the passion that has made so many Bimota products such fun to ride, and to be honest, show off. You ride some bikes because you have to, but you ride a Bimota like this because you want to!”

Can’t argue with that – so, start saving!

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