A hydraulic clutch in a dirt bike typically has the same fibers, plates, and clutch basket as a standard, cable-driven clutch system. What sets a hydraulic clutch apart is the system that is used to disengage the clutch plates. Fluid is compressed down and transported through a line in order to separate the clutch when the lever is pulled in on a hydraulic clutch system.
On the other hand, the clutch lever pulls on a cable connected to an arm in a standard cable clutch system. This arm is then used to separate the clutch plates. Over the years, many dirt-bike enthusiasts have replaced their standard cable clutch systems with modern hydraulic ones. Basically, hydraulic clutches replace the standard cables and wires with a special hydraulic fluid, which is smoother and requires much less by way of maintenance and upkeep.
Purpose of the Hydraulic clutch System
Originally, dirt bike clutch levers were operated with the help of a plethora of wires and cables. The shift to hydraulic clutches initially occurred because they are easier to operate and maintain than cable-actuated clutch levers. Stiffer clutch springs could be used to make the clutch lever stronger and more durable, due to the easier pull of the hydraulic system. This also gave the dirt bike in question more torque to work with.
Manufacturing a hydraulic clutch system and installing it in a dirt bike can often be easier than the process involved in the production and installation of a cable-actuated clutch system. A hydraulic clutch lever also provides more consistency and greater durability than the traditional cable variety.
A clutch slave cylinder and a push rod replace the cables pulling on an arm in a hydraulic system. Since the slave cylinder and push rod are both inside of the engine, they typically stay out of harm’s way and are rarely damaged during minor accidents and mishaps. This lends greater longevity to the dirt-bike as a whole.
The clutch lever in a hydraulic system is typically connected to a reservoir filled with a special fluid. This reservoir is known as the ‘master cylinder’. When the lever is pulled in, this causes compression in the hydraulic fluid, thus building up the pressure. A pulse of fluid flows down the hose to the slave cylinder due to the enhanced pressure.
Inside the slave cylinder, the fluid pushes against a piston, making it in turn put pressure on a rod. This rod extends from one side of the engine to the other. On the left side is the shift lever while on the right is the clutch basket of the dirt bike. This rod subsequently is pushed into a position where it is able to pull the plates apart, thus disengaging the clutch.
One of the problems associated with dirt bike clutch systems is the fact that when the clutches get hot, the distance between the fiber plates decreases due to heat-induced expansion. This alters the point of release of the clutch levers. When the clutch plates in a cable-actuated system heat up or cool down, the clutches need to be manually adjusted.
The fluid in a hydraulic clutch system, on the other hand, self-adjusts constantly in order to compensate for heat as well as general wear and tear. This ensures that the rider always has a consistent feel for the dirt bike clutch lever. Moreover, the self-adjusting hydraulic fluid also keeps the clutch system operating optimally without much manual oversight.
The first dirt bikes to feature hydraulic clutches were released in the year 1998. By the early 2000s, the popularity of hydraulic clutch systems for motorbikes had soared exponentially. Both American and Japanese two-wheeler brands now sell models with hydraulic clutch levers. On the other hand, motorcycle owners who are dissatisfied with their cable-actuated clutches can also install a hydraulic clutch system in their vehicle by investing in a set of high-quality aftermarket clutch levers.
How to Go Hydraulic?
Using an aftermarket hydraulic clutch kit is the best option for those who did not purchase a dirt-bike with pre-installed hydraulic clutches. Upgrading from a cable-actuated clutch system to a hydraulic one is not very difficult, especially for those who are familiar with dirt-bikes and know what they’re doing.
Motorbikes with cable-actuated clutch systems do not have in-built master cylinders, fluid reservoirs, and slave units. Therefore, when buying aftermarket hydraulic clutch levers, one must always be careful to ensure that the unit includes a hydraulic slave cylinder that can be externally bolted to the cases. This will help move the actuating arm that was previously pulled by the clutch cable.
Apart from occasional replacement of the hydraulic fluid, a hydraulic clutch system requires very little upkeep and maintenance. Hydraulic clutches also enhance the functionality and durability of the dirt-bike. For the best results, however, bike owners must only purchase high-quality aftermarket clutch levers from reputed manufacturers or retailers.