40 CFR 205.168-1 - General requirements.
(a) Each manufacturer of motorcycle exhaust systems manufactured for Federally regulated motorcycles and distributed in commerce in the United States which are subject to the noise emission standards prescribed in this subpart and not exempted in accordance with subpart A, § 205.5:
(2) Must only manufacture exhaust systems which conform to the applicable noise emission standard established in § 205.166 of this regulation when installed on any Federally regulated motorcycle for which it has been designed and marketed.
(b) The manufacturer who is required to conduct testing to demonstrate compliance with a particular standard must satisfy all other provisions of this subpart applicable to that standard.
(1) Not withstanding paragraph (a)(1) of this section, the manufacturer may distribute in commerce exhaust systems of that category for up to 90 days if weather or other conditions beyond the control of the manufacturer make testing of a category impossible and if the following conditions are met:
(e) A manufacturer is required to verify all categories of exhaust systems within his product line for each class of Federally regulated motorcycle for which it is designed and marketed. A category of a replacement exhaust system is defined by a separate combination of at least the following parameters:
(1)Muffler/Silencer: (i) Volume; (ii) type of absorption material; (iii) amount of absorption material; (iv) length; (v) diameter; (vi) directional flow of exhaust gas; (vii) interior construction; (viii) shell and inner construction material; (ix) number of header pipes entering muffler; and (x) specific motorcycle application.
(2)Expansion Chamber: (i) Volume; (ii) diameter; (iii) construction material; (iv) directional flow of exhaust gas; (v) length; and (vi) specific motorcycle application.
(3)Spark Arrestors: (i) Volume; (ii) construction material; (iii) directional flow of exhaust gas; (iv) length; (v) diameter, and (vi) specific motorcycle application.
(4)Other Exhaust System Components: (i) Volume; (ii) shape; (iii) length; (iv) diameter; (v) material; (vi) directional flow of exhaust gas; and (vii) specific motorcycle application.
(g) Original equipment exhaust systems that are also sold as replacement systems for the same motorcycle configuration need not be tested under this subpart if they have been tested or represented in a test report under subpart D of this part.
(i) Modify the test exhaust system and demonstrate by testing that it meets applicable standards. The manufacturer must modify all production exhaust systems of the same category in the same manner as the test exhaust system before distribution in commerce.