Bimota, a Italian manufacturer of custom and production motorcycles has introduced the KB4, a modern retro themed sportbike at EICMA 2021 along with the KB4RC which is a naked version of the full faired sport. These models were the result of the hookup between the bike maker and Kawasaki. Bimota actually name their models after the engine sitting inside the frame - DB for Ducati, SB for Suzuki, KB for Kawasaki. In this article, let's see something about this masterpiece because it grabbed my attention with it's uniqueness which I explain later. Now, let's kick start with the design elements.
Bodyworks are fully made of carbon fiber and Bimota claims that the design of the motorbike is inspired from their early Kawasaki engined models from the 70s & 80s. Though it sourced the powertrain from the Japanese manufacturer, it is completely different and lighter than the donor. Front end of the fairing incorporates a circular headlamp which remembers something of the past. The fairings are designed in such a way to expose the engine's crankcase and it runs up to the tail which also looks cool.
Fuel tank perfectly match it's lines with the rear cowl and the dual tone color scheme of red & white suits the nature of the bike. All chassis components are mounted on a steel trellis frame including the engine which acts as a stressed member. Coming to the engine, it is a 1,043cc inline 4 cylinder, LC, 4V/C, DOHC unit producing about 142HP & 111Nm of peak power & torque at 10,000rpm & 8,000rpm respectively. As said previously, the power source is borrowed from the Ninja 1000SX which also have similar output numbers. Remember I said something about the motorbike's uniqueness? Let's see...
Generally, radiator in a liquid or water cooled engine acts as a heat exchanger in which the hot coolant's temperature will be lowered and sent to the coolant jacket again for the cycle. These heat exchangers will be mounted in front of the engine normally to get exposed by atmospheric air which helps in cooling. This is a conventional method and also it affects the parameters like wheelbase and rake angle of the motorbike. Here in the KB4, Bimota's design & engineering team placed the radiator under the tail section of the motorbike which is much more complex than we think because it includes the rerouting of coolant line by repositioning the whole lot of electronics present there.
By this, they've achieved a shorter wheelbase of 1,390mm where the donor have about 1,440mm. It looks like the difference in numbers are very low but actually it makes big difference in handling characteristics of the bike especially at corners. Now surely a question will be raised inside you about the radiator. Yes... If the radiator is present under the tail section, what about the air flow required for the heat exchanging process? Right? That's why the front end is designed with intake ducts on either side of the fairing. Air enters through that and travels via carbon fiber tunnel which is directly routed to the radiator. Interesting and unique, isn't it?
But in order to work efficiently, I think the motorbike should be at minimal speed to draw air via intake ducts which forces it to pass through the radiator. Steel trellis frame is suspended using 43mm USD NIX30 forks from Ohlins at the front and TTX36 shock at the rear from Ohlins which is fully adjustable by hand clickers hooked with aluminum alloy swingarm. With dual 320mm disc rotors at the front clamped with Brembo Stylema calipers and 220mm disc at the rear, the bike should have a better stopping power and hell of a grip with the help of rubbers from Pirelli.
Fuel tank's capacity is 19L and overall the motorbike weighs about 189kg dry which is much more lighter than the donor Ninja 1000SX weighing 238kg. Though the motorbike looks retroish, it contains handful of electronics such as cornering management system, cruise control, bi-directional quickshifter, traction control and power modes. TFT instrument cluster with smartphone connectivity feature and switchgears are also derived from Kawasaki.
Image courtesy : Bimota
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