(A)     Every motor vehicle driven or operated upon the highways of this city shall at all times be equipped with an adequate muffler or exhaust system in constant operation and properly maintained to prevent any excessive or unusual noise.  No muffler or exhaust system shall be equipped with a cut-out, bypass, or similar device.  No person shall modify the exhaust system of a motor vehicle in a manner which will amplify or increase the noise of the vehicle above that emitted by the muffler originally installed in the vehicle, and the original muffler shall comply with all the requirements of this section.
   (B)     As used in this section, "MUFFLER" means every device consisting of a series of chambers or baffle plates or other mechanical design for the purpose of receiving exhaust gas from an internal combustion engine or turbine wheels for the purpose of receiving exhaust gas from a diesel engine, both of which are effective in reducing noise. 
(ILCS Ch. 625, Act 5, §§ 12-602) ('64 Code, § 21-142)  Penalty, see § 70.999