2006-2012 Honda TRX90 TRX90EX/X Service Manual, Page 24Get this manual
GENERAL INFORMATION
EMISSION CONTROL SYSTEMS
The U.SEnvironmental Protection Agency (EPA), and the California Air Resources Board (CAR B) require that off-road ATV comply with applicable exhaust emissions standards during its useful life, when operated and maintained according to the instruction provided
SOURCE OF EMISSIONS
The combustion process produces carbon monoxide, oxides of nitrogen and hydrocarbonsControl of hydrocarbons and oxides of nitrogen is very important because, under certain conditions, they react to form photochemical smog when subjected to sunlightCarbon monoxide does not react in the same way, but it is toxicHonda Motor Co Ltdutilizes appropriate carburetor settings as well as other systems to reduce carbon monoxide and hydrocarbons