Quickshifters

Generally while downshifting, what we do is hold the clutch lever and shift down the gears. After downshifting, again we pop the clutch and twist the throttle. The moment we hold the clutch lever, power delivery to the rear wheel is paused until we pop the clutch again. In motorsports, the time in which the rear wheel is not powered may led you to lose the competition. In tracks, one tenth of the second also matters.

As the name says, quickshifter helps in making the gear shifting process quick. It is developed to decrease the time that the rear wheel not getting power. In most of the cases, motorsport technology is truncated for the road legal performance oriented motorbikes. Quickshifters are categorized into two types. First one is for upshifting. Second one is for both upshifting and downshifting. Before diving into the quickshifters, first let's see what's happening when we shift the gears up or down.

In general downshifting, rider closes the throttle and pulls the clutch lever. By doing that, friction and steel plates disengage thereby the power from the engine doesn't flow to the rear wheel via transmission system. After that, rider downshifts using the gear lever and reengage the drivetrain by popping up the clutch lever and the throttle input is given finally.

To decrease the time in doing that, riders will do clutchless upshifting by leaving the throttle for unloading the power in drivetrain. After that, upshifting will be done and finally the rider gives the throttle input. The main reason for leaving the throttle is to avoid damage in gears. Because, if the gear is shifted while the power is flowing from the engine, gears will undergo great amount of stress which may lead to gearbox failure. That's why input to the throttle is not given while doing clutchless shifting. In clutchless upshifting, to avoid the motion of throttle, quickshifter comes to action.

Generally, this is done by cutting the fuel supply or spark needed for the combustion to happen momentarily. In carbureted engines, cutting the fuel supply for a little moment is not possible. So therefore, cutting the spark will be the solution. But by doing this, unburned fuel will come out from the combustion chamber which results in deposition of unburned fuel in the catalytic converter. So, this system is effective only for fuel injected motorbikes.


Near the gear shifter assembly, a transducer will be present. Transducer is a device which converts one form of energy into a readable signal. Transducer have a input that is then converted into electric signal. Transducer near the shifter assembly always looks for any change in pressure near the shifter or near the shifter linkage. When it senses any change, the signal will be sent to the Electronic Control Unit (ECU). The ECU starts the action of cutting down the fuel and power supply momentarily. In fuel injected motorbikes, everything is fully controlled electronically which also make the quickshifter to work effectively. By this action of cutting fuel and spark supply, the power produced in the engine is paused momentarily thus you can able to do clutchless upshift without doing any action in the throttle. Thus the time taken for the shifting process is reduced and starts to become an advantage for the riders in motorsports.


The other type is using a mechanical switch which is spring loaded. The same process happens but only the actuating mechanism differs. But, most of the manufacturers opt for transducers fitted quickshifters as they are more effective. What we've seen is the unidirectional quikshifter which is used only for upshifting. But, there is also quickshifters present for downshifting.

Generally, while downshifting what we'll do is, hold the clutch, downshift and pop the clutch. Finally we give the throttle. But here in quickshifter's downshifting mechanism, the process is quite different. You may heard of the term rev matching. While downshifting, engine's RPM will increase naturally. Many of us slightly blip the throttle to match the RPM increase. By doing this, we can able to neglect the increase in engine's RPM unwantedly. For this blipping process, autoblippers are used along with the bidirectional quickshifters. Or else, you may need a slipper clutch in your motorbike. As i said previously, due to the implementation of technology in motorbikes, everything is achieved precisely. Ignition and injection parameters are controlled electronically by the ECU. To achieve this, autoblippers are used. While downshifting, this will blip the engine which slightly increase the engine's RPM resulting in perfect rev matching.

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