Section 86.410-90 - Emission standards for 1990 and later model year motorcycles(a)(1) Exhaust emissions from 1990 and later model year gasoline-fueled, natural gas-fueled and liquefied petroleum gas-fueled motorcycles shall not exceed (compliance with these standards is optional prior to the 1997 model year for natural gas-fueled and liquefied petroleum gas-fueled motorcycles): (i)Hydrocarbons. 5.0 grams per vehicle kilometer.(ii)Carbon monoxide. 12 grams per vehicle kilometer.(2) Exhaust emissions from 1990 and later model year methanol-fueled motorcycles shall not exceed:(i)Total hydrocarbon equivalent. 5.0 grams per vehicle kilometer.(ii)Carbon monoxide. 12 grams per vehicle kilometer.(3) The standards set forth in paragraphs (a) (1) and (2) of this section refer to the exhaust emitted over driving schedule as set forth in subpart F and measured and calculated in accordance with those procedures.(b) No crankcase emissions shall be discharged into the ambient atmosphere from any new motorcycle subject to this subpart.54 FR 14539, Apr. 11, 1989, as amended at 59 FR 48512, Sept. 21, 1994