While the styling team worked up a clay model of the winning sketch to see how successfully it transferred to actual curves, angles and shapes-eventually using 3D CAD to drop a model of the bodywork onto a current Hayabusa rolling chassis to see how everything fit-several small engineering teams got busy. The engine group grabbed horsepower and durability research they'd done prior to the start of the 'Busa II project and put a finer point on the numbers via a fresh round of powerplant tweaks and dyno testing. The fuel-injection team began working on specific air/fuel settings the new engine would likely need in the differing markets in which it'd be sold with help from a computerized rolling-road test bed. The chassis team investigated the firmer spring and damping settings the more powerful and better-handling machine would require. New wheels and brakes were sourced and analyzed, as were chassis bits such as the lower triple clamp, which would need to be more rigid if the braking guys opted for more powerful radially mounted calipers-which they did. Each new component or upgrade affected another part of the whole, which forced the teams to work closely as they methodically put all the main pieces of the puzzle in place.
Prototype and pre-production testing went relatively smoothly, the new 'Busa offering a bit more of everything compared to the old bike: more power, more braking power, improved wheel control via upgraded suspension, a bit more stability at speed and, of course, a nastier, more athletic look. Let's take a look at how Suzuki squeezed so much more chassis and engine performance from the old bike...
The chassis and engine upgrades that allow the new Hayabusa to run up front
Suzuki's new Hayabusa looks in many ways similar to the original bike, but it's almost entirely new-sleeker, more powerful, electronically smarter, better braked and even better looking.
Although Suzuki decided early on it would carry the old Hayabusa's engine over to the new model, the company also had an ambitious power target-"above 190 bhp" to be specific. To get there with an inline-four designed a decade earlier, Suzuki engineers tweaked and massaged nearly the entire powerplant, first designing a more compact cylinder head filled with titanium valves in the same sizes as before (33mm intakes, 27.5mm exhausts), single valve springs to save weight and a new hydraulic cam-chain tensioner. Below came redesigned (and lighter) pistons with a smaller pin diameter (18mm vs. 20mm) running with 2mm more stroke (81.0 x 65.0mm vs. 81.0 x 63.0mm) in SCEM-coated cylinders for 1340cc of displacement, 42cc more than before. Those new pistons reach Top Dead Center with more compression force (12.5:1 vs. 11.0:1), while rings got an ion-plating treatment for better cylinder sealing, reduced friction, reduced oil consumption and improved reliability. The con-rods holding said pistons are now shot-peened chromoly steel for additional strength.
Down below is a reworked and stronger crankshaft driving a heavier-duty clutch and a transmission filled with heat-treated, shot-peened cogs. Final-drive gearing is now 43/18, a touch shorter than before. Revised cylinder ventilation reduces pumping losses, while a gear-driven counterbalancer and back-torque limited clutch continue on as in the old bike. On the intake side, smaller throttle bodies with 44mm GSX-R1000-type injectors handle fuel atomization, while a reworked, GSX-R1000-type air cleaner and ram-air system help cram more clean atmosphere into the throttle bodies. Out back, a redesigned 4-into-2-into-1-into-2 exhaust with catalyzer and oxygen sensor help the new 'Busa meet Euro 3 and Tier 2 environmental requirements, while massive, triangularly shaped, GSX-R1000-type dual mufflers offer increased volume and reduced noise. There's also a new, more curved radiator assembly, a larger oil cooler and dual cooling fans controlled by an also-new ECU (electronic control unit, or the bike's computerized brain).