Technical Information  37.2007 Page 3
TI_37_2007_30_01_02.fm
1. Technical description
1.1 Long-life air filter system with cyclone 
pre-separation
The long-life air filter system with cyclone pre-
separation provides extended filter service intervals 
to more than a year on average.
For this reason:
The filter cover should only be removed and the 
air filter replaced if there is a noticeable loss of 
power or more than a year of extended use has 
passed since the last filter change. Do not clean 
the air filter as damage to the filter element and 
consequential engine damage could occur. 
The tank housing (1) is shown with all its individual 
parts in order to illustrate the underlying principle.
Contaminated air is drawn in, through the tank 
housing (1) and is swirled by the cyclone pre-
separation integrated into the tank housing (1).
This rotation deflects the larger and heavier 
suspended particles downwards and returns them 
to the tank housing (1).
The contaminated air streams through the molded 
hose (3) to the fan-side half of the crankcase (2) and 
out of the machine.
This precleaned air flows through the air filter 
system – comprising the air filter (4) and auxiliary 
filter (5) – to the carburetor (6).  This principle 
extends the filter life to more than a year on average 
and the service life of the shortblock at the same 
time.
2
370TI001 KN
1
3
4
5
6