S&S 49-State engines have been certified under the requirements of the letter of guidance issued by the EPA on July 25, 2007. This letter of guidance details a procedure for engine manufacturers to certify motorcycle engines to meet exhaust emissions standards. The basis of this letter of guidance is that a bike built using one of these certified engines is considered a certified vehicle by the EPA. The EPA allows these certified engines to be used by individuals and small volume manufacturers without their bike needing to be tested or certified with the EPA. There are a few requirements though for the bikes gearing, weight, labeling, and exhaust that the builder must meet for the bike to be considered a certified vehicle. The following video discusses these requirements and what is included with S&S 49-State engines