Honda Rebel 250 2016 Owner's Manual page 104

Exhaust Emission Control System
The exhaust emission control system consists of
appropriate carburetor settings, and no
adjustment should be made except idle speed
adjustment with the throttle stop screw.
Evaporative Emission Control System
50 STATE (meets California)
An evaporative emissions control system uses a
canister filled with charcoal to absorb fuel vapor
from the fuel tank and carburetor while the
engine is off. The vapor is drawn into the
engine and burned while riding.
Emission Control Systems
Crankcase Emissions 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.
Fuel Permeation Emission Control
The fuel tank, fuel hoses, and fuel vapor charge
hoses use fuel permeation control technologies
to prevent fuel vapor emissions.
Tampering with these components to reduce or
defeat the effectiveness of the fuel permeation
technologies is prohibited.
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