Honda Goldwing GL1800 Owner's Manual page 216

Emission Control Systems
Evaporative Emission Control System
This motorcycle complies with the requirements of the California Air Resources
Board (CARB) evaporative emission regulations. Fuel vapor from the fuel tank
is directed into the charcoal canister and air cleaner where it is adsorbed and
stored while the engine is stopped. When the engine is running and the purge
control solenoid valve is open, fuel vapor in the charcoal canister and air cleaner
is drawn into the engine through the throttle body.
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 the intake manifold.
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Technical Information