Code of Federal Regulations Title 40. Protection of Environment § 40.205.155 Motorcycle class and manufacturer abbreviation

(i) Gasoline—two stroke.

(ii) Gasoline—four stroke.

(iii) Gasoline—rotary.

(iv) Other.

(i) Number of cylinders.

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

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

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

(iii) Spark arrestors.

(iv) Other exhaust system components.