Emissions Notice
California regulates motorcycle aftermarket parts that have the potential to impact emissions. In most cases, the sale and use of emissions related aftermarket parts on motorcycles is prohibited unless it is either a “replacement part” as defined by California, or is a specifically authorized use of that part as reflected in an Executive Order (“EO Part.”) The California Air Resources Board (CARB) regulates aftermarket parts and has promulgated regulations that essentially place all emissions related aftermarket parts into three categories:
Replacement Parts are aftermarket parts that ARB considers to be functionally equivalent to the stock part they are intended to replace, and therefore would not impact the emissions from these vehicles. These parts are appropriate for sale and use on motorcycles used on or off the public highways. For aftermarket exhaust systems and parts, there are two applicable scenarios:
(a) If the motorcycle’s stock exhaust system does not contain a catalytic converter, then an aftermarket exhaust part is a replacement part as long as the part does not remove or replace any emission control equipment originally attached to the stock exhaust system, such as oxygen sensors.
(b) If the motorcycle’s stock exhaust system contains a catalytic converter in the manifold section of the stock exhaust system, then an aftermarket muffler positioned downstream from the catalytic converter (i.e. cat-back) is a replacement part as long as the part does not remove or replace any emission control equipment originally attached to the stock exhaust system.