Stripped of its bodywork, the new Hayabusa has a familiar shape. While the engine has a 2mm-longer stroke for a 42cc bump in displacement to 1340cc, most internal and external dimensions are unchanged. Likewise, the frame is essentially identical but for the removal of the centerstand brackets, and the swingarm has an additional rib inside each main spar to increase stiffness by 10 percent. The rake is sharper at 23.4 degrees (from 24.2), and trail has been tightened up from 98mm to 93mm.
The 4-into-2-into-1-into-2 exhaust system has a catalytic converter and an oxygen sensor underneath the engine. Stricter emissions standards are responsible for most of the bike's seven-pound jump in claimed dry weight (and we suspect that-given Suzuki's recent fudging with dry weights-the increase is even greater).
This two-piece hub from the back-torque-limiting clutch is an identical setup to the original bike's. Now dubbed Suzuki Clutch Assist System, the cam profile works in both directions to provide a slipper effect on deceleration as well as increase preload on the plates under acceleration, allowing the use of lighter springs to reduce lever effort. The clutch's fiber plates have a new material that improves feel at the lever.
Plenty of tires stood ready at the bike's Road America introduction. The OEM BT-015 Bridgestones have a similar tread pattern, compound and construction to those used on the GSX-R1000. The 1300's front tire has a slightly different belt angle, while the rear has an extra breaker belt under a lighter circumferential steel monospiral belt, all for increased stiffness. Bigger front and rear sprockets are used to reduce chain noise and result in a slightly shorter overall ratio and a 5mm reduction in wheelbase.
The SCEM (Suzuki Composite Electrochemical Material)-coated cylinders now have large cutouts to allow air to escape when the piston descends, reducing pumping losses. New pistons are stronger and have smaller-diameter pins and a modified crown shape to bump compression from 11.0:1 to 12.5:1. The connecting rods are now shot-peened, the piston rings have a chrome-nitride PVD coating like the GSX-Rs and titanium valves are used instead of steel. Included valve angle and valve sizes are unchanged, but the lighter material allows more aggressive lift numbers and the use of one spring per valve as opposed to two.
While the old Hayabusa had a single-injector, single-butterfly EFI setup (left), the new bike has the company's latest SDTV arrangement (right), with dual throttle valves, dual 12-hole injectors and Idle Speed Control. Like the GSX-R1000, the Hayabusa has S-DMS, which allows the rider to choose among three engine-control maps via a handlebar switch.
The steering damper has sprouted a tiny piggyback reservoir but is not electronically controlled like the 1000's. The new radiator is narrower, shorter and thinner but has slightly more heat-rejection capacity and a second cooling fan. Similarly, the oil cooler's heat-dissipation capacity has also been increased.
One of the first-generation's few upgrades over the years was the addition of TiN coating to the fork tubes in '03; the new model has DLC on its 43mm tubes. The front brakes are now current with four-piston, two-pad radial mount calipers, with slightly smaller-diameter (from 320mm to 310mm) and thicker (from 5.0 to 5.5mm) discs. The rear disc is also thicker, but 20mm larger in diameter than previously, and the caliper has been moved from under the swingarm to on top in an arrangement similar to the GSX-R600 and 750.
Valve arrangement: DOHC inline-four, 4 valves/cyl.
Bore x stroke: 81.0 x 65.0mm
Compression ratio: 12.5:1
Induction: SDTV EFI with dual throttle valves and two injectors per cylinder, 44mm throttle bodies
Front tire: 120/70ZR-17 BridgestoneBT-015F M
Rear tire: 190/50ZR-17 Bridgestone BT-015R M
Rake/trail: 23.4 deg./3.7 in. (93mm)
Wheelbase: 58.3 in. (1480mm)
Seat height: 31.7 in. (805mm)
Fuel capacity: 5.5 gal. (21L)
Weight: 485 lbs. (220kg) dry