The clutch has the job of regulating the delivery of the engine’s power to the gearbox and drivetrain through infinite points of friction, not just ‘on’ or ‘off’. By doing this, the clutch gives the rider the control needed to provide traction and drive when and where it is required, no matter what the riding situation.
Needless to say, it is absolutely vital your clutch is working properly so as to maximize your riding experience and minimize the chance of having trouble with rear wheel traction.
The outer basket is driven via the primary drive gear directly off the crank – whenever the engine is running, it is spinning. The inner hub is splined directly onto the gearbox input shaft. The large tabs on the outer rim of the friction plates locate into the slots on the basket, and as the basket spins the friction plates are driven around. The steel friction plates are splined onto the inner hub.
Pressure from the clutch springs forces the pressure plates inwards; this force causes the fiber plates to grab the steel plates and drives them around, which in turn drive the inner hub and therefore the gearbox input shaft. The clutch is deemed ‘engaged’ when the level is in the fully out position.
When you pull the clutch lever, you are disengaging the clutch by mechanically forcing the pressure plate outwards against the clutch springs: without the inward force from the pressure plate, the fiber plates slip against the steel and drive is reduced or lost completely.
The correct adjustment position for the clutch lever is when you have 1 to 2 mm of free play before pressure is applied to the pushrod and when the lever is pulled in, the clutch is completely disengaged before you are crushing the lever. Cables usually have two adjustments by a couple of locknuts. Hydraulic clutches have adjustment inside the lever and adjust the free play between the lever and the master cylinder’s inner piston.
How to replace the clutchedSome motorcycles have a clutch inspection cover. These are usually held on with six to eight bolts and are easily removed to access the clutch. Some motorcycles don’t have this cover, so you may have to remove the entire engine cover to access the clutch. This will mean draining coolant, oil and depending on your motorcycle model removing the kickstart lever and often the foot brake lever and oil pipes. If you have to remove this engine cover you will need to replace the gasket, so don’t forget to buy a fresh gasket...
Once you have the cover removed, the clutch can easily be disassembled by removing the five or six bolts with springs under them. Once free the pressure plate will pull off and then the fiber and steel friction plates can be pulled out. Note the order as you remove them, as often there are different plates making up the clutch and they are installed in a specific order – this is especially true for bigger motorcycles.
Inspect and measure according to the manufacturer’s specifications and replace any component that is out of specification. If you need to replace or repair the clutch basket you will require special tools to remove the center lock nut.Tag: Clutch Clutch-Springs Wheel-Traction Friction Clutch-Play Maintenance Replace Repair Mechanical Gearbox