2007-2009 Honda TRX300EX TRX300X service manual, Page 27Get this manual
GENERAL INFORMATION
EMISSION CONTROL SYSTEMS
The .SEnvironmental Protection Agency (EPA)and the California Air Resources Board (CARB) requ ire that off-road ATV comply with applicable exhaust emissions standards and evaporative 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 Ltduti lizes various systems to reduce carbon monoxide, oxides of nitrogen, and hydrocarbon
EXHAUST EMISSION CONTROL SYSTEM
The exhaust emission control system is composed of lean carburetor settingno adjustments should be mad except for idle speed adjustment with the throttle stop screwThe exhaust emission control system is separate from the crankcase emission control system