Air Filter - Husqvarna K 750 Workshop Manual

Cylinder
cooling air
In
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AIR FILTER

Function
Husqvarna Active Air Filtration is a filter system that
effectively purifies the air to the engine in three separate steps
and according to three different purification principles:
1. Centrifugal cleaning is the first step in the purification of
the inlet air.
The fins on the flywheel supply the cylinder with cooling air
at the same time as they act as the active part in the centrifugal
cleaning of the engine's inlet air. An inlet nozzle is fitted close to
the fins on the flywheel. The centrifugal force means that large
particles do not follow the curved air currents to the nozzle, but
are thrown to the outside of the nozzle. Only very small dust
particles manage to swing with the air currents to the inlet.
2. Foam plastic filter is the next level of separation in the
To carburettor
purification process. An air deflector guides and distributes the
air across the whole filter surface, which means that the whole of
the filter is better utilised and is fouled evenly across the surface.
The filter is steeped in oil and is made up of three layers with
different pore sizes.
3. The paper filter primarily provides effective protection
should the foam plastic filter, on account of inadequate care, lets
dust through.
4. Service filter's sole task is to prevent foreign objects from
entering the engine during service work. The service filter should
only be replaced if it is damaged.
Filter service
Centrifugal cleaning
The inlet duct should be inspected and any deposits re moved
in connection with filter replacement. Dust from dry cutting is
cleaned off using compressed air Material from wet cutting nor-
mally needs to be scraped off mechanically. Check that the seal
on the foam plastic filter's filter base is intact. Fit the seal correctly
in the air duct cover!
Foam plastic filter
New filters are supplied steeped in the correct amount of filter
oil. The replacement frequency is dependent on a number of fac-
tors and therefore cannot be generally stated. Unfortunately there
is no easy method to assess a used filter's remaining capacity, and
it is even harder when the machine's history is not known.
However, in all safety it can be said that if dust particles can be
discerned on top of the filter (clean side) it is spent.
Paper filter
The paper filter should not be clean, but is replaced with a new
one. The replacement frequency depends very much on the care
of the foam plastic filter.
Exercise extreme care when the filter is dismantled so that dust
particles do not fall down through the service filter. Vacuum clea-
ning is the best method to remove spillage and to clean the gasket
around the service filter.
A useful rule for filter replacement is: Replace the paper filter
when the yellow paper colour is no longer visible.
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