Secondary Air System - KTM 950 ADVENTURE 2003 Manual

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Secondary air system

The secondary air system supplies fresh air to the emissions in the exhaust port, resulting in the afterburning (oxidation) of the
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emissions. A line leads from the filter box to the control valve which opens as soon as the throttle valves are opened. The
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line continues to the reed valves in the cylinder heads which are actuated by the pressure pulsation in the exhaust system. As a
result, cleansed fresh air arrives in the exhaust port. The oxygen content in the air and the high exhaust gas temperature cause the
emissions to oxidize.
If the throttle valves are closed and the engine goes into an overrun condition, the underpressure in the intake port will rise and the
control valve will close. This prevents exhaust backfire (combustion of the unburned fuel/air mixture).
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