Catalytic Silencer - APRILIA RALLY 50 - 2000 Manual

a
Avoid parking the Rally 50 catalytic versi-
on near dry brush wood or in places easi-
ly accessible to children, as the catalytic
silencer becomes extremely hot during use; be
very careful and avoid any kind of contact before
it has completely cooled down.
The catalytic vehicle is fitted with a silencer with met-
al catalytic converter of the "platinum-rhodium biva-
lent" type.
This device provides for the oxidation of the CO (car-
bon monoxide) and of the HC (unburned hydrocar-
bons) contained in the exhaust gases, changing
them into carbon dioxide and steam, respectively.
Due to the catalytic reaction, the high temperature
reached by the exhaust gases makes for the burning
of the oil particles, thus keeping the silencer clean
and eliminating the exhaust fumes.
2
To have the catalytic converter function correctly and
for long and to reduce possible problems regarding
the soiling of the thermal unit and of the exhaust, it is
necessary 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 relatively high rpm, even
if only for a few seconds, but rather frequently.
What has been stated above assumes particular im-
portance for the cold starting of the engine: in this
case, in order to reach a rpm regime sufficient to en-
able the "priming" of the catalytic reaction, just make
sure that the temperature of the thermal unit has
reached at least 50°C, which generally occurs a few
seconds after starting the engine.
a
Do not use leaded petrol, since it causes
the destruction of the catalytic converter.
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