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.

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.