'61HN252' by American Honda Motor Co. - Page 48 of 540
http://services.honda.com/ServiceManual/SVC_MNL/61HN253/61HN2...
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3/9/2008 10:29 PM
[2005-2008] [TRX500 FA/FGA]
GENERAL INFORMATION
EMISSION CONTROL SYSTEMS
The U.S. Environmental Protection Agency (EPA), and California Air Resources Board (CARB) require that this off-road ATV
comply with applicable exhaust emissions standards during its useful life, when operated and maintained according to the
instructions provided.
SOURCE OF EMISSIONS
The combustion process produces oxide of nitrogen, carbon monoxide and hydrocarbons. Controlling oxide of nitrogen
and hydrocarbon emissions is very important because, under certain conditions, they react to form photochemical smog
when subjected to sunlight. Carbon monoxide does not react in the same way, but it is toxic.
Honda Motor Co., Ltd. utilizes lean carburetor settings as well as other systems to reduce oxides of nitrogen, carbon mon-
oxide and hydrocarbons.
EXHAUST EMISSION CONTROL SYSTEM
The exhaust emission control system is composed of a lean carburetor setting, and no adjustments should be made except
idle speed adjustment with the throttle stop screw. The exhaust emission control system is separate from the crankcase
emission control systems.
CRANKCASE EMISSION CONTROL SYSTEM
The engine is equipped with a closed crankcase system to prevent discharging crankcase emissions into the atmosphere.
Blow-by gas is returned to the combustion chamber through the air cleaner and carburetor.
CARBURETOR
AIR CLEANER HOUSING
CRANKCASE BREATHER HOSE
Fresh air
Blow-by gas
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