Valve, Secondary air supply BMW HP4/S, 1000R/RR/XR

The secondary air system of the motorcycle adds fresh air from the air filter box ("airbox") to the exhaust gas side in specific states of the engine load. This means that unburned hydrocarbons in the exhaust gas are "burned" afterwards. This reduces carbon monoxide emissions by up to 40%.

Hydrocarbon emissions are reduced by a maximum of 30%. The secondary air is not used to dilute the exhaust gases - as claimed in some internet forums. The secondary air valve controls the air supply and prevents exhaust gases from flowing back into the air filter box. To prevent the catalyst from overheating, the secondary air valve interrupts the air supply at high speeds. In motor vehicles, on the other hand, the secondary air system is only active when the engine is cold (max. 90 seconds) and the air is actively blown in by a secondary air pump.

Takes care of:

• BMW HP4 / S, 1000R / RR / XR