The clutch itself is removed and replaced with a slipper clutch. When you brake on these race bikes they stop very quickly and it is difficult for the rider to match the speed of the engine to the road. It is no use trying to slip the clutch as the rear wheel just skips, therefore we need a clutch that automatically slips when the bike is decelerating which allows the rear wheel speed to be faster than the engine speed and makes going into a corner a whole lot smoother.
The throttle bodies have to remain the same, but that doesn’t mean we can’t fettle them as well. The GSX-R1000 has two sets of butterflies, of which we take the second set off but leave the actuating mechanism for reasons that will be discussed later. What this does is allow more airflow into the engine and more airflow means more power basically.
The exhaust is all hand made of course by Yoshimura, and has the two exit holes at the end. Now Yoshimura won’t tell us why they do this as it gives the bike another 2 - 2.5 BHP over the singular exit hole, which is a 1% increase. We’ve even taken one apart but can’t fathom why it gives such a benefit. Now a 1% increase may not sound like much but lots of 1% increases add up to a significant amount and that is what we look for.
The other main difference between the race bike and a standard one is the collector box, this is where the four header pipes come out of the engine and collect together under the engine. We use two different arrangements here that gives us slightly different engine characteristics. A four-into-one affair gives us more top end power, whereas a four-into-two-into-one gives us significantly more torque.
