Honda XL350R 1984 Shop Manual page 17

GENERAL INFORMATION
EMISSION CONTROL SYSTEM
The U.S. Environmental Protection Agency and California Air Resources Board (CARB) require manufacturers to certify that
their motorcycles comply with applicable exhaust emissions standards during their useful life, when operated and maintained
according to the instructions provided, and that motorcycles built after January 1, 1983 comply with applicable noise emis-
sion standards for one year or 6,000 km (3,730 miles) after the time of sale to the ultimate purchaser, when operated and
maintained according to the instructions provided. Compliance with the terms of t he Distributor's Warranties for Honda
Motorcycle Emission Control Systems is necessary in order to keep the emissions system warranty in effect.
Source Of Emissions
The combustion process produces carbon monoxide and hydrocarbons. Control of hydrocarbons 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 carbon monoxide and hydrocarbons.
EXHAUST EM ISSION CONTROL SYSTEM
The exhaust emission control system is composed of lean carburetor settings, and no adjustments should be made except idle
speed adjustment with the throttle stOP screw.
CRANKCASE EMISSION CONTROL SYSTEM
The engine is equipped with a closed crankcase system which routes crankcase emissions through the air cleaner and into the
combustion chamber. Condensed crankcase vapors are accumulated in a storage tank which must be emptied periodically. See
the Maintenance Schedule in Section
3.
EVAPORATIVE EMISSION CONTROL
SYST EM (California model only)
This model complies with California Air Resources
Board requirements for evaporative emission regula-
tions.
Fuel vapor from the fuel tank is routed into a char-
coal canister where it is absorbed and stored while
the engine is stopped. When the engine is running,
and the purge control diaphragm valve is open, fuel
vapor in the charcoal canister is drawn into the
engine through the carburetor.
! J ' - - - - A I R C LEANER
BREATHER SEPARATOR
"<"-- - -- --TRANSPARENT SECT ION
<==
FRESH AIR
- BLOW-BY GAS
-~-----DRAIN
PLUG
FUEL TANK
AIR
~I
CARB {RI
CANISTE R/"
p.e.v.
DRAIN
1-13