Emission Control Systems; Source Of Emissions; Exhaust Emission Control System; Crankcase Emission Control System - Honda TRX450R Service Manual

GENERAL INFORMATION
EMISSION CONTROL SYSTEMS
The U.S. Environmental Protection Agency (EPA), and the California Air Resources Board (CARB) require that off-road
motorcycle or 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 hydrocarbons. Control of hydrocarbons and
oxides of nitrogen 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 various systems to reduce carbon monoxide, oxides of nitrogen, and hydrocarbon and
hydrocarbon.
EXHAUST EMISSION CONTROL SYSTEM
The exhaust emission control system is composed of lean carburetor setting, no adjustments should be made except for
high altitude setting and idle speed adjustment with the throttle stop screw. The exhaust emission control system is
separate from the crankcase emission control system.
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.
'04-'05:
CARBURETOR
CRANKCASE
BREATHER HOSE
AIR CLEANER
<^~ I Fresh air
Blow-by gas
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