From Drag Specialties:
Important Emissions Notice
Disclaimer: Emission-related parts, devices, or systems for non-OEM emission control system equipped motorcycles, as well as slip-on mufflers that mount downstream of and which do not inhibit the original design, function, or performance of the original emission control system, are considered Replacement Parts by the California Air Resources Board (CARB) and are therefore exempt from prohibitions of the California Code of Regulations Section 27156 by reason of Section 2222(j). CARB does not, however, permit the use of aftermarket emission-related parts, devices, or systems that alter the performance of OEM emission-related devices unless CARB has issued an Executive Order, other than on racing vehicles on closed courses. More emission-related information is available at
www.arb.ca.gov and also on this MIC PDF
Products shown may be designed, manufactured, intended, and sold for use on competition vehicles that are operated only on closed course racing circuits unless otherwise noted, and use of the same on public roads or lands may be a violation of local, state, and/or federal laws. By offering products for sale, Drag Specialties makes no representation or warranty as to whether the items offered for sale are legal for the use for which they are purchased.
Check your applicable laws and manufacturer’s publication(s) and/or website(s) for manufacturer’s warranty, maintenance, safety, mounting, and any regulatory compliance/non-compliance information.
Certain emissions regulatory compliance/non-compliance information provided by the manufacturer can be found by clicking on the brand below.
From Vance & Hines:
Emissions Notice to Customers in California
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 (ARB) regulates aftermarket parts and has promulgated regulations that essentially place all emissions related aftermarket parts into three categories:
(1) Replacement Parts
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.
(2) Executive Order Parts
Executive Order Parts are aftermarket parts that ARB has evaluated and determined do not adversely impact emissions, and thereby are granted an Executive Order (EO), which allows the part to be sold and used on specified motorcycles. Any aftermarket exhaust system that replaces or otherwise impacts emission control equipment, including catalytic converters, requires an EO to be sold and used on a motorcycle used on or off a public highway.
(3) Competition Use Only Parts
Competition Use Only Parts may not be sold or used on a motorcycle that is used on or off the public highways other than those motorcycles used exclusively for competition. Competition Use Only Parts are aftermarket parts that replace or otherwise interfere with the operation of an emission control device, such as a catalytic converter or oxygen sensor, and may be sold and used on a motorcycle that is used only for closed course competition.
