Section 21226 Of Article 5. Operation Of Motorized Scooters From California Vehicle Code >> Division 11. >> Chapter 1. >> Article 5.

. (a) A person shall not sell or offer for sale a motorized scooter that produces a maximum noise level exceeding 80 dbA at a distance of 50 feet from the centerline of travel when tested in accordance with Society of Automotive Engineers (SAE) Recommended Practice J331 JAN00.
  (b) A motorized scooter, as defined in subdivision (b) of Section 407.5, shall at all times be equipped with a muffler meeting the requirements of this section, in constant operation and properly maintained to prevent any excessive or unusual noise, and a muffler or exhaust system shall not be equipped with a cutout, bypass, or similar device.
  (c) A motorized scooter, as defined in subdivision (b) of Section 407.5, operated off the highways shall at all times be equipped with a muffler meeting the requirements of this section, in constant operation and properly maintained to prevent any excessive or unusual noise, and a muffler or exhaust system shall not be equipped with a cutout, bypass, or similar device.
  (d) A person shall not modify the exhaust system of a motorized scooter in a manner that will amplify or increase the noise level emitted by the motor of the scooter so that it is not in compliance with this section or exceeds the noise level limit established by subdivision (a). A person shall not operate a motorized scooter with an exhaust system so modified.