Honda SH300 2006 Manual page 52

GENERAL INFORMATION
EMISSION CONTROL SYSTEMS
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 sub-
jected 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 hydrocarbons.
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 housing and throttle body. Condensed
crankcase vapors are accumulated in a crankcase breather drain plug which must be emptied periodically (page 4-7).
THROTTLE BODY
1-48
CRANKCASE BREATHER HOSE
AIR CLEANER HOUSING
BREATHER
DRAIN PLUG
Fresh Air
Blow-by Gas