How Does a Hydraulic Clutch Work in a Motorcycle?
In recent years, many motorcycles and bikes are being made with hydraulic clutches instead of mechanical ones. So, what exactly is a hydraulic clutch and how does it work?
On older vehicles and two-wheelers, most clutches worked with the help of a cog system. This cog system facilitated the changing of gears during the process of shifting. However, a hydraulic clutch is slightly different because it has fewer components than its mechanical counterpart. It just has a reservoir filled with hydraulic fluid which becomes pressurized whenever the clutch lever is used. This allows the hydraulic clutch lever to engage a new gear while disengaging the previous one.
The Purpose of a Clutch Lever in a Motorcycle
The primary purpose of the clutch is to disconnect the engine from the transmission and the drivetrain system temporarily. Without the process of initial disconnection, it is almost impossible to mate the transmission with the idle engine and move a geared motorcycle forward, while it is in a stationary position.
While it is possible to shift gears without making use of the clutch when the motorcycle is in motion, this might cause a rocky transition and the resultant grinding might permanently damage the gearbox if the process is performed incorrectly.
Typically, riders will use their left hand to control the clutch lever. A complex hydraulic system connects this lever to a circular clutch assembly located close to the engine. The clutch assembly incorporates a pressure plate which should be facing the engine cover. On a motorcycle, the clutch lever is pulled so that the transmission can be disengaged and then synced with the engine so that the vehicle can move forward.
How the Clutch System Works
Springs bolted on the outside facilitate the functioning of the pressure plate which acts as a lid pulling out and pushing in to create compressions and decompressions in the “Clutch Pack”. A series of alternately placed friction and steel plates constitutes the clutch pack.
On their outer and inner circumference, these plates have “teeth” that enable the clutch system to function as intended. All the plates are stacked together closely, so that the teeth of the friction plates can interlock effectively with the grooves or slots on an outer basket which in turn covers the entire assembly. The steel plates, placed between the friction plates, can the interlock with the grooves or slots on a small inner hub. This hub has a smaller diameter than the outer basket and is located adjacent to it inside.
The outer basket and its gears are connected to and driven by the crankshaft of the engine. The inner hub rotates with the transmission's input shaft and is splined on it. Hence, when the clutch lever is used, the compressed springs located on the pressure plate allow everything to get sandwiched together. Power is hence transferred to the transmission from the engine when the friction and the steel disks rotate together.
Advantages of a Hydraulic Clutch
In a hydraulic clutch, force is conveyed with the help of a fluid stored in a reservoir within the motorcycle. While cable or mechanical clutches have been around for much longer, many people prefer hydraulic clutches because, with them, the driver doesn't need to worry about fraying cables and messy lubricants.
Moreover, one does not need to manually adjust the slack from time to time in order to keep the cable from getting loose. This is because a hydraulic clutch system will self-adjust when the plates sustain wear and tear, as long as there is some fluid available in the reservoir. Hence, throughout the life of a hydraulic clutch, the engagement point remains the same.
Hydraulic clutches are also easier to tune and modulate. As there are two cylinders amplifying the grip strength, the lever pull is typically lighter and quite consistent. Hence, a hydraulic clutch is more intuitive and easier to use than the traditional, cable version.
Moreover, it requires much less by way of maintenance and upkeep. Essentially, one can just install it and then forget about it for the next few years. The only maintenance work required is that every few years, the hydraulic fluid will need to be replaced.
However, potential buyers should keep in mind that hydraulic clutch levers are typically more expensive than mechanical ones. They are also harder to repair, in the unlikely scenario that a seal fails to work. Therefore, one should be prepared to spend more money upfront on a hydraulic clutch, although this expenditure is balanced out in the long term by the greater durability and functionality of the product.
Now that you know all about hydraulic clutch levers and their many features and advantages, it is time to decide what type of clutch system you want in your motorcycle. For the best results, you should purchase aftermarket mechanical or hydraulic clutch levers from a reputed manufacturer or brand. This will ensure that you get a product which is well-designed and made from high-quality materials.