From a press release issued by the AMA:

EPA ISSUES NEW STREETBIKE EMISSIONS RULES

PICKERINGTON, Ohio — The American Motorcyclist Association (AMA) reports that road-going motorcycles nationwide will be required to meet new strict emissions standards beginning with the 2006 models under rules released by the federal Environmental Protection Agency.

But the new rules, issued December 23, give small-volume motorcycle manufacturers a break in meeting the new standards, and provide for exemptions for certain motorcycles.

The EPA rules set new emissions standards that are the same as those adopted by the state of California, but will go into effect two years after California’s standards. The first tier of the new national standards will go into effect in 2006 and a second tier in 2010.

The new national emissions standards are expected to result in an increased use of fuel injection and catalytic converters on new motorcycles. Some motorcycles sold in the United States already meet California’s strict 2008 standards, which are the same as the planned federal EPA 2010 standard.

The California standard that begins with the current model year, 2004, and the federal standard that will take effect for the 2006 model year, require new motorcycles to emit no more than 1.4 grams per kilometer traveled of hydrocarbons and nitrogen oxides, and 12 grams per kilometer of carbon monoxide.

Before passage of the new federal rule, federal emissions standards for street motorcycles were 5.0 grams of hydrocarbons and 12 grams of carbon monoxide per kilometer traveled.

Under the new rule, manufacturers who build fewer than 3,000 motorcycles a year, and who have fewer than 500 employees, don’t need to meet the first-tier emissions standards until 2008. They also aren’t required to meet the second-tier standards.

The EPA also provides certain exemptions for “kit” and custom motorcycles.

Nothing in the new rules changes what owners may do legally to customize their motorcycles.