Since its introduction in 1999, Suzuki's GSX-1300R has been feeding the need for speed. The Hayabusa is named after the Japanese word for the world's fastest animal, the Peregrine Falcon, which is capable of diving at speeds over 200mph. Touted as the world's fastest production motorcycle, it is possible to make a motorcycle that is capable of 186mph right off the showroom floor any faster?
One of the first modifications performed on a motorcycle, replacing the stock exhaust can provide a better flow of spent gases and improve performance. Most stock systems are heavy and restrictive due to the addition of emissions-required components. Aftermarket exhausts are available as full systems or slip-on type replacements. Full systems replace the stock header, mid-pipe, and silencer to provide a smoother flow and increased top-end performance with an additional gain of up to 11 horsepower. The increase in power is noticeable at high-speeds, but tends to lose lower and mid-range performance. Full systems range in price from £520 to £1,625.
Slip-on exhausts replace only the silencer and mid-pipe, providing a relatively inexpensive boost in power. Although top-end gains are minimal, the power spread is broader in the lower to mid-range with smaller gains of four to six horsepower. Slip-on exhaust prices range from £195 to £520.
Fuel and Air
Additional air and fuel requirements from changing the exhaust system are often overlooked by the average street rider. Replacing the stock air filter with an aftermarket filter, as provided by K&N or BMC, will allow a better flow of fresh air. This flow is then handled by the electronic fuel injection (EFI) system. The stock fuel-injection system settings, or "map", are set for the stock intake/exhaust set-up, providing the correct amount of fuel to air ratio to power the bike. As you change the intake/exhaust layout, this ratio is thrown off balance as the improved exhaust and intake flow also allows more air into the engine, leaning out the mixture. An aftermarket EFI controller, such as Dynojet's Power Commander and Bazzaz Performance's Z-Fi Fuel Management System, allow you to fine-tune the fuel map, enrichening and leaning the fuel curve as needed to provide massive gains in performance.
Delimiting The 'Busa
More power, and more speed, can be found by de-restricting the Hayabusa. Speed limiters, preventing the bike from passing the 186mph point have been installed on the Hayabusa and other large-capacity sportbikes. Removing this built-in limit is possible with a derestriction kit, such as Schnitz Racing's modified gear-position sensor. However, these speed-limiter bypasses often make the digital gear indicator equipped on 2006 and newer models read a constant "sixth" gear, regardless of actual gear position.
Aside from modifications that create more power, additional speed can be found by reducing the Hayabusa's weight. With the 2009 model weighing in at 260 Kilogram ready to ride, losing a few pounds will benefit performance across the board. Installing an aftermarket exhaust can help shed weight. In this case, installing a Megaphone system from Brock's Performance reduced as much as 15.9 Kilogram from the total weight. Changing the stock wheels for lighter forged aluminium wheels can lose an additional 4.99 to 6.35 Kilogram, increasing both straight line speed and handling performance by shedding weight.
Look into improving your Hayabusa's stopping power. Simple improvements, such as stainless steel brake lines, can pay dividends when you are astride a rocket ship hurtling along at triple digit speeds. Firming up the suspension, which is generally softer due to the bike's alleged sport-touring heritage, can also improve handling for the occasional back road thrash. Other methods of increasing the performance of a Hayabusa, such as turbocharging and running nitrous-oxide, are available, but can decrease the longevity of the motor, so be warned!