With
a suspension geometry that consists of fork angle and height, motorcycles
are designed. Changing of components from the suspension geometry of
motorcycles can affect the geometry, therefore, it is advisable that the
front and rear ends of motorcycles must match each other. When the front and
rear shock absorber components interact properly, the optimum result can be
achieved.
Design of Motorcycle Shock Absorber
Usually, the shock absorbers of motorcycles are pressurized. Under gas
pressure, the fluid is put, and the fluid and the gas pressure are kept
apart from each other with the help of a piston. On the top of the shock
absorber, this separating is directly fixed, or it is kept in a separate
reservoir. There is another type of shock absorber is found for the
motorcycle, in which everything is fitted in the main cylinder tube. This
tube is also called as internal gas reservoir. Nitrozen is used for making
the pressurization of the fluid. This pressurization prevent the cavitation
of the fluid, that is useful for making the shock absorbing more even. The
external reservoirs assist in controlling the temperature of the fluid,
which increases the service life of both the components and the fluid. In
motorcycle shock absorbers, there are integrated temperature compensation.
The fluid starts to flow more easily with the increasing temperature of the
fluid, but this flow of fluid is control inside the absorbers. Therefore,
the effect of shock absorbing is quite independent of the temperature. In
some modern motorcycle shock absorbers, the individual-adjustment of
rebounding damping and compression damping is possible. There is also
adjustable either mechanical or hydraulic pre-loading system is found in the
motorcycle shock absorbers.
Fluid Flow in Motorcycle Shock Absorbers
The fluid of the shock absorbers is forced through the needle valves at a
slow rate (Fig. 3). It can also be forced through a number of other
apertures, which are present in the piston (Fig. 4). The shims regulate the
flow of fluid (Fig. 5). The shims are the steel washers. At high pressure of
fluid flow, the shims are deflected from their position. The features of the
damping action can be altered by changing the thickness, number or diameter
of the shims.
When the shock absorbers of motorcycles get compression due to the movement
of the motorcycles, through the needle valves (combination of return valves
and compression valves), the fluid starts to flow in the piston road. During
rapid compression, when the velocity of the piston is high, the needle
valves are not sufficient for the flowing of the fluid. In this case the
fluid starts to flow through the shims, which are present just beneath the
piston. The fluid is forced into the external fluid chamber, which is
displaced through the piston rod. A separate compressive valve is used
through which the fluid is being force into the external fluid chamber.
Although, this valve is attached with the shims, which open during the high
piston velocity.
Setting of Shock Absorbers in Bikes & Motorcycles
- Place the bike or the motorcycle on its stand.
- To keep the suspension of the vehicle in full extended position,
raise the rear end of the vehicle.
- Either from the lower edge of the rear mud guard or from any point
just above the rear wheel axle marked by a piece of tape, the distance
is measured (R1).
- Similar measurement is done on the front axle also. (Between bottom
of the upper fork crown and the front wheel axle) (F1).
- For applying load on the springs, the motorcycle or the bike is
allowed (With our rider). The measurement process is repeated (R2, F2).
- In this step, take the measurements (same as step E), but this time
the measurement is taken with rider (R3, F3).
Inspection & Maintenance of Two-Wheeler Shock Absorbers
- Soft detergent can be used for external wash of these shock
absorbers.
- Compressed air can also be used for this purpose.
- The place used for cleaning the shock absorbers, should be clean.
- The bump rubber should also be lifted, while cleaning it.
- Frequent oil spray should be applied on these shock absorbers and
these should keep clean.
- Detergent never be used for cleaning these absorbers, because
detergent may erode the external surface.
- Brake cleaner and thinner can be used for quick drying-up of the
surface of these absorbers.
- Normally, the pressure of gas of the absorbers should not be changed
of altered. Some special purpose equipments can be used for altering the
gas pressure of these absorbers.
Inspection of Two-Wheeler Shock Absorbers
- For more frequent and smoother play, the ball joints should be
checked regularly.
- For preventing any leakage and damage, the piston shafts of the
absorbers should be checked.
- The external reservoirs of the absorbers must also be checked.
- Prevent the excessive wear and tear of different rubber equipments
present within the absorbers.
- Ensure the secure and tight fastening of the shock-absorbers in the
two-wheelers.
