257.707 Muffler, engine, power mechanism, and exhaust system; requirements; prohibitions.
(1) A motor vehicle, including a motorcycle or moped, shall at all times be equipped with a muffler in good working order and in constant operation to prevent excessive or unusual noise and annoying smoke. A person shall not remove, destroy, or damage any of the baffles contained in the muffler, nor shall a person use a muffler cutout, bypass, or similar device upon a motorcycle or moped on a highway or street.
(2) The engine and power mechanism of a motor vehicle shall be so equipped and adjusted as to prevent the escape of excessive fumes or smoke.
(3) A motor vehicle shall at all times be equipped with a properly operating exhaust system which shall include a tailpipe and resonator on a vehicle where the original design included a tailpipe and resonator.