Last month our project Hayabusa received a heavily updated front end. New forks with internally lowered springs allowed us to install a Beringer radial brake set up alongside a Performance Machine wheel. The upgraded front half of the bike needed to have an equally trick rear end to keep pace, and considering the power this Hayabusa will be cranking out it had to be performance focused. No glam here-just go.
At the core of our rear end upgrade is a Roaring Toyz swingarm. A lot of folks are unaware that this Florida-based custom sportbike firm also built a top-level drag bike that was consistently running seven-second quarter miles. Furthermore, the company's owner has been a lifelong roadracer and builds his bikes (even the fat tire bling machines) to be ridden hard.
Although Roaring Toyz swingarms are available in any finish imaginable, we opted for raw aluminum to help suggest pure power and performance. Once the new paintjob is sprayed over the bodywork it should contrast nicely and actually stand out more than if it was powdercoated or chromed. At first glance we were concerned that it isn't braced, but once we put on X-ray glasses we saw that the 'arm actually has internal underbracing to keep its overall size down but still strong as a steel ox.
Attached to the Roaring Toyz swingarm is a billet radial brake caliper from the same company. It offers superior power over the puny traditional rear caliper, and considering we want all the stopping force we can get it was the perfect upgrade.
The center of attention is the sinister looking ten-spoker from Performance Machine. We opted for a stock-sized, six-inch rim simply because we didn't want the extra weight and offset that comes with a 240 setup. Of course, a fat 240 rear would look fantastic and be perfectly fine for street use, but at the strip and for land speed racing it's not exactly ideal. Wrapped around it is a Dunlop Q2 to match the front, also in the OE recommended tire size.
Tucked away out of immediate sight is one of our 'Busa's best-kept chassis secrets: a Progressive Suspension 465 Series shock. Designed specifically for extended swingarm sportbikes, the 465 Series shock has a significantly stronger spring and internal components than the stocker in order to handle the increased demand. A shorter overall stroke also means the shock is physically smaller and allows the bike to be lowered without altering the linkage drastically. Instead of squatting under the turbo motor's massive power and increased leverage from the stretch, the shock is designed to hold firm and not collapse, conducive to maximum drive.
The chassis has been fully refreshed and upgraded from front to rear. It's now more stout and capable of handling the extreme forces from day to day on the street and week-to-week at the strip. The brakes are loads stronger (and better looking) than the stock units in both the front and rear, the stock wheels were replaced with lighter performance-focused hoops and the suspension upgrades on both ends allowed us to properly lower the bike without sacrificing stability or performance. If we simply bolted back on the bodywork and lights this bike would be ready for action, but our plans run much deeper than that.