40 CFR § 205.155 - Motorcycle class and manufacturer abbreviation.

---
identifier: "/us/cfr/t40/s205.155"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 205.155 - Motorcycle class and manufacturer abbreviation."
title_number: 40
title_name: "Protection of Environment"
section_number: "205.155"
section_name: "Motorcycle class and manufacturer abbreviation."
chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"
subchapter_number: "G"
subchapter_name: "NOISE ABATEMENT PROGRAMS"
part_number: "205"
part_name: "TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "Secs. 6, 10, 11, 13, Pub. L. 92-574, 86 Stat. 1234 (42 U.S.C. 4905, 4909, 4910, 4912)."
regulatory_source: "41 FR 15544, Apr. 13, 1976, unless otherwise noted."
cfr_part: "205"
---


# 205.155 Motorcycle class and manufacturer abbreviation.

(a) Motorcycles must be grouped into classes determined by separate combinations of the following parameters:

(1) Engine type:

(i) Gasoline—two stroke.

(ii) Gasoline—four stroke.

(iii) Gasoline—rotary.

(iv) Other.

(2) Engine displacement.

(3) Engine configuration:

(i) Number of cylinders.

(ii) Cylinder arrangement (*i.e.*, in line, opposed, etc.).

(4) Exhaust system:

(i) Muffler: (A) Type, (B) Location, (C) Number.

(ii) Expansion chambers: (A) Location, (B) Size.

(iii) Spark arrestors.

(iv) Other exhaust system components.