40 CFR 205.165 - Definitions.
(2)Exhaust header pipe means any tube of constant diameter which conducts exhaust gas from an engine exhaust port to other exhaust system components which provide noise attenuation. Tubes with cross connections or internal baffling are not considered to be “exhaust header pipes.”
(4)Federally regulated motorcycle means, for the purpose of this subpart, any motorcyle subject to the noise standards of subpart D of this part.
(5)Federal standards means, for the purpose of this subpart, the standards specified in § 205.152(a)(1), (2) and (3).
(7)Stock configuration means that no modifications have been made to the orginal equipment motorcycle that would affect the noise emissions of the vehicle when measured according to the acceleration test procedure.
(8)Test exhaust system means an exhaust system in Selective Enforcement Audit test sample.