The clutch is one of the most vital components of a two-wheeler. It is a mechanical device that sits between the engine and the gearbox and is responsible for engaging or disengaging the engine’s drive to the transmission. A clutch assembly comprises a flywheel, a pressure plate and friction plates. We have explained the workings of a motorcycle clutch in one of our previous articles, and you can fully understand how a clutch function by referencing that article. To recap, the flywheel is driven by the engine, while the pressure plate holds the friction plates tightly against it. When the clutch lever is released, the drive is transmitted to the rear wheel as the entire assembly acts as a single unit. When the clutch lever is pressed, the friction plates are separated from the flywheel and hence the drive is not transmitted to the rear wheel and you can make a gear shift.
Motorcycle clutches are of two types - wet and dry. Wet clutches are bathed in engine oil for heat dissipation and lubrication and are located inside the engine casing. It is a multi-plate assembly and is used in high torque applications as the lubricant (or oil) dissipates the heat arising from the friction between the plates. The wear and tear and maintenance are relatively low although, due to lubrication, the torque transmitting capacity is slightly reduced. On the other hand, dry clutches are not bathed in engine oil and hence located outside the engine casing, in direct contact with the atmosphere.
Now, with the knowledge that your motorcycle clutch would most likely be a wet multi-plate unit, let us take a look at symptoms of a dying motorcycle clutch: -
Clutch slippage is a problem wherein the pressure plate cannot hold the friction plates against the flywheel tightly as required, resulting in an erratic transfer of power. Over time, the friction plates lose their quality to provide sufficient friction, owing to excessive heat and wear and tear. They are not able to hold together very well, resulting in slippage. This also means that the flywheel and pressure plate are locked, but are still rotating at different speeds. In essence, this means that the engine's power is not perfectly transferred to the rear wheel. You can feel this happening when you whack open the throttle, the engine revs shoot up, but your motorcycle does not accelerate as it should correspond with your throttle input.
The clutch is a robust and heavy assembly, and that is why the clutch lever is generally quite firm and resistive, especially if the clutch assembly is not a slipper-and-assist type. If your clutch lever becomes soft like wool, it might be a sign of a worn-out clutch. Also, if the consistency of operation, the smoothness of engaging clutch, shifting gears etc., is erratic, you might want to visit your service centre. In extreme cases, even when you release the clutch lever, the lever still stays pressed in.
Unusual noise, pulsations and vibrations
Sound is an excellent indicator of the health of any vehicle. If you hear your clutch rattling, pulsating, clinging or making unusual noises or if you feel something is grinding underneath, this might indicate a worn-out clutch. When you feel excessive vibrations or pulsations upon operating the clutch or changing gears or feel an excessive shuddering of the motorcycle, especially when you start to drive off or release the clutch after a shift, you need to have your clutch examined.
An unusual gear shift sense
Gear shifts are directly related to the clutch so quite naturally if the clutch is worn out, the shifts will be unusual. A worn-out clutch will result in a jerky and very unpredictable gear shift. If you experience A. false neutrals quite often, B. hear grinding and squeaking when you shift, C. if the in-gear acceleration is not what it used to be, D. if some gears feel particularly easy to engage while some feel particularly difficult, it is time to check the health of your clutch.
Another sign of a worn-out clutch is reduced fuel efficiency. A worn-out clutch means that the engine is not able to transmit its power correctly to the gearbox. This would result in lower acceleration and speed for any given increase in engine speed, resulting in lower mileage. If your motorcycle’s mileage has dropped along with a drop in performance, it is time to have those plates checked.
Now, apart from the symptoms, we would also like to share a few tips to increase your clutch's life.
Don’t ride the clutch
A habit of riding the clutch, or in other words, keeping the clutch lever partially pressed at most times affects the life of the clutch. Riding the clutch over a prolonged period wears out the clutch assembly components prematurely. Use the clutch only when you have to shift gears, make a clean shift and release the clutch lever once done to ensure the longevity of your motorcycle’s clutch.
To avoid a sudden shoot up of the revs after a downshift, you should slightly blip the throttle before releasing the clutch to shoot the engine revs up and match the revs for the downshift for the desired lower gear. Motorcycles with a slipper clutch overcome this problem, but if yours doesn’t have one, ensure that you blip the throttle and rev-match to minimise the damage caused.
Avoid unnecessary, overly aggressive downshifts
As an extension of the above point, you should avoid downshifting aggressively when it is not necessary. Some riders have this habit of shifting down a couple of gears when it is not needed, purely for the noise and its drama. Sure, if you are riding fast you will sometimes need to downshift aggressively, especially around sharper corners. However, always remember that smoothness, not theatrics are key to being fast. You should try to be smooth and be in the right gear rather than put the engine and clutch under pressure for no real gains.
To sum it all up, the clutch is one of the most vital components of your motorcycle. It is usually designed to last for a very long time, but if you don’t take the necessary care, it will wear out sooner than expected. Drive responsibly and safeguard your clutch to get optimal performance and fuel efficiency from your motorcycle in the long term.