The document discusses the components and operation of a motorcycle clutch. It describes the clutch as a mechanical device that engages and disengages the driving shaft from the driven shaft, allowing gear changes. The key components of a clutch include the clutch outer, center, plates, pressure plate, springs, lever and cable. The clutch works by compressing springs when the lever is pressed, causing the pressure plate to expand and separate the friction plates from the clutch plates, disengaging the drive. Wet clutches are lubricated by engine oil while dry clutches are sealed and external to the engine case.

1. NED University of Engineering and Technology
MUHAMMAD UMAIR AKRAM 1
Clutch of a Motor bike
What is clutch?
The mechanical device that engages or disengages the driving shaft from the driven shaft as actually the clutch.
Means the device that is used to transmit the power is clutch. In every type of road vehicles there is the need of a
clutch to shift the power form through gear shift. Generally the Clutches are cable operated in motor bikes and in
cars, buses, trucks they are not cable operated. The two shafts connected to the clutches are the main engine
shaft and the next is the one that is connected to the output. The clutch is not a single element in actual it is the
assembly of the different elements having their own functionality and these assembled part together produces
the functional clutch. The elements/parts of the clutch are:
1. Clutch outer
2. Clutch center
3. Lifter
4. Pressure plate
5. Friction disk/Disk friction
6. Clutch plates
7. Springs
8. Spring dampers
9. Set rings
10. Clutch cable & lever
Clutch Outer:
You may also call it the housing of the clutch. It is one of its side there is a teeth plate attached i.e. riveted. This
side of the clutch is connected with the driving shaft i.e. to the transmission box. All the other elements will be
assembled in its other side.
Clutch Center:
For CD-70 this element is named as drive plate and for other heavy bike this element is named as clutch center. It
has the inner hole broached means it have teethes on inner hole which is directly connected with to the engine.
Clutch plates:
There are two types of clutch plates one is disk friction plates and other one is steel plate. Disk friction plates have
high values of coefficient of frictions which is used for firm gripping during the engage condition. This plate have
the teeth at its outer diameter. These friction plates are coated with some material most of the time it is ceramic.
Whereas the clutch disk plate have the teeth at its inside diameter that are used to make connection with the
clutch center which is connected with driving shaft. During disengage condition these plates get separated from
friction plates by very small distance so that the transmission becomes stationary.
Pressure plate:
It is the moving part of the clutch assembly which works against clutch spring tension. It releases the clamping
action on the clutch plates when the clutch lever is engaged.
Springs:
These spring have greater importance in the clutch assembly. We can say it is the element that is causing
principle of clutch to be performed. Generally there are in total four spring used. These springs use their tension
power for the frim engaging of the clutch with driving shaft. And uses it compression to be disengaged.
Clutch lever & Cable:
The steel cable is used for connecting the lever with the clutch assembly. Usually this lever is attached on the left
side of the handle of bike.
Set ring:
It is actually the lock ring that is used to lock down the all the plates in the clutch outer.

2. NED University of Engineering and Technology
MUHAMMAD UMAIR AKRAM 2
How clutch works?
Under normal circumstances clutch is in engaging condition. Whenever the rider presses the lever of the clutch it
compresses the springs which causes the pressure plate to expand and thus the disk friction plates gets separated
from the clutch plates so the driving and driven shafts rotates at different speeds and at the same time rider had
to change the gear (up or down) and will release the clutch lever. The time between disengaging and engaging
of clutch with main or driveline shaft must be as small as possible when you are riding at high speed means you
have to change the gears with in very small time. This shifting with in smallest possible time is called the perfect
shifting of gears.
Types of clutch:
There are following two types of clutches:
1. Wet clutch
2. Dry clutch
Wet clutch:
As the name indicates in this type of clutch the oil is circulated in its assembly i.e. the whole clutch is packed with
engine assembly and oil is used for lubrication. Generally tacking almost all the bikes uses this type of clutches.
Dry clutch:
This is the one which as kept away from the oil. And this clutch assembly is outside of the engine case. The
connecting points are sealed so that there is no chance for oil to get in to it.