High Altitude Carburetor Adjustment - Honda CRF230F 2019 Manual

High Altitude Carburetor Adjustment

At high altitude, the standard carburetor
air-fuel mixture will be too rich. Performance
will decrease, and fuel consumption will
increase. A very rich mixture will also foul the
spark plug and cause hard starting. Operation at
an altitude that differs from that at which this
engine was certified, for extended periods of
time, may increase emissions.
High altitude performance can be improved by
specific modifications to the carburetor. If you
always operate your engine at altitudes above
6,500 feet (2,000 meters), have your servicing
dealer perform this carburetor modification.
This engine, when operated at high altitude
with the carburetor modifications for high
altitude use, will meet each emission standard
throughout its useful life.
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Technical Information
Even with carburetor modification, engine
horsepower will decrease about 3.5% for each
1,000-foot (300-meter) increase in altitude. The
effect of altitude on horsepower will be greater
than this if no carburetor modification is made.
NOTICE
When the carburetor has been modified for
high altitude operation, the air-fuel mixture
will be too lean for low altitude use. Operation
at altitudes below 5,000 feet (1,500 meters)
with a modified carburetor may cause the
engine to overheat and result in serious engine
damage. For use at low altitudes, have your
servicing dealer return the carburetor to
original factory specifications.