Do you mean down shifting through blimping the throttle and dropping the clutch for the gear all at the same time? Its just down shifting without having to slowly feed the clutch back in. As you feed the clutch in slowly your allowing the engine to slow and the revs to climb until they match. If u release it and they don't match, you get wheel hop, sliding, false neutral etc....
If you blip the throttle to match your revs up higher for the gear your going down to, then you can shift straight into a gear and not have to feed the bike slowly. And since a bike works best under power and not coasting, it is best to quickly get through a gear, rather than slowly enter it.
On top end racebikes the slipper-clutch takes care of 80% of all your throttle blipping needs. But from my understanding, any racer worth his salt can downshift through as many gears as he needs, 'matching revs' and letting the clutch out (even slightly) in evry one.
yes, they let the clutch out - I do - as do many of my racer friends, slowly.
but with the blip you can kick it in gear quicker and get the clutch out quicker and have less room need to get the revs to match. You never seriously "dump" the clutch. But you've got a lot more enganged then having to just slowly work into it w/o a blip.
If you let the clutch out slowly without blipping the throttle, it will wear out your clutch unneccicarily. It also has the same effect as using the rear brake. Proper shifting on a sportbike means unloading the gear dogs at the same time you shift. For example, under hard acceleration, if you preload the lever, then close the gas, the 'reverse' engine torque will momentarily 'unload' the gears and allow the upshift. It works the same way for downshifting but it is MUCH more difficult to clutchless downshift and even proffesional racers use clutch slipping when downshifting. Check out your Gixxer manual, it actually says to roll off the throttle, pull the clutch in and shift AT THE SAME TIME. Remember, you only need to pull the clutch in just enough to 'fan' the plates, dont pull it all te way back, its just a waste of time.
ya unloading the thing is neccessary. Maybe you mean this.... but blimping loads it up, pull the clutch in for a split second at the same time shifing. The point is, the minute you pull in the clutch you'll be unloading, and you can easily slip her into gear.
This is also known as "The Heel-Toe Method" in the world of driving. Basically you are using the heel, or the left side of your right foot on the brake,and your toes on the throttle to acheive the same thing as blipping a motorcycle. It avoids disturbing the weight transfer the same way for both cars and bikes.
This is essential to smooth riding and driving. It's good for the clutch as well.