Each state has its own emissions and inspection requirements. In California this is managed by the Air Resources Board (CARB for short). CARB has determined that certain aftermarket motorcycle parts are not legal for sale or highway use in the state of California. Items subject to this determination include certain exhausts, fuel controllers and other parts which might affect the emissions of a vehicle.
RevZilla has determined to the best of its ability based upon information provided by its suppliers which items are CARB approved and which items are not and an informative warning will be displayed to any customers in California attempting to purchase a non-CARB approved product.
Items which are not CARB approved may still be purchased and utilized in the state of California provided that they are not used on a public road (i.e. only used on a closed course or offroad).
For more information, please refer the CARB's information page aftermarket parts.