Catalytic Silencer - APRILIA SCARABEO 50 - 1997 Manual


Avoid parking the vehicle
catalytic version near dry brush
wood or in places easily accessi-
ble to children, as the catalytic silencer
becomes extremely hot during use; be
very careful and avoid any kind of con-
tact before it has completely cooled
down.
26 use and maintenance Scarabeo 50
The catalytic Scarabeo 50 is fitted with a si-
lencer with metal catalytic converter of the
"platinum-rhodium bivalent" type.
This device provides for the oxidation of
the CO (carbon monoxide) and of the HC
(unburned hydrocarbons) contained in the
exhaust gases, changing them into carbon
dioxide and steam, respectively.
Due to the catalytic reaction, the high tem-
perature reached by the exhaust gases
makes for the burning of the oil particles,
thus keeping the silencer clean and elimi-
nating the exhaust fumes.
To have the catalytic converter function
correctly and for long and to reduce possi-
ble problems regarding the soiling of the
thermal unit and of the exhaust, it is neces-
sary to avoid covering long distances with
the engine running at constantly low rpm.
It is sufficient to alternate these periods
with periods in which the engine runs at rel-
atively high rpm, even if only for a few sec-
onds, but rather frequently.
What has been stated above assumes par-
ticular importance for the cold starting of
the engine: in this case, in order to reach a
rpm regime sufficient to enable the
"priming" of the catalytic reaction, just
make sure that the temperature of the ther-
mal unit has reached at least 50°C, which
generally occurs a few seconds after start-
ing the engine.

Do not use leaded petrol, since it
causes the destruction of the
catalytic converter.