Honda CB350 Repair Manual page 112

FUEL SYSTEM 107
Removing the needle seat
8. Remove the phillips head set screw
from the float needle seat stay and re—
move the needle seat by lifting it out.
9. Unscrew the pilot screw.
Inspection
1. Clean the carburetor body and
float bowl in a carburetor cleaner or sol—
vent and dry thoroughly.
2. Use compressed air to blow air and
fuel passages clear.
3. Clean all fuel jets in the same man—
ner.
CAUTION: Do not insert anything
into the jet passages to clear them; use
air pressure only.
4. Inspect the carburetor body for any
vibration or stress cracks.
5. Check the condition of the throttle
slide. Smooth movement of the slide on
the carburetor body is imperative. If the
slide sticks or binds at any point from full
closed to wide open, replace it.
6. Inspect the needle jet and the
needle. The needle must be free of nicks
or score marks along its tapered portion.
More often, however, these components
will need to be replaced because of nor—
mal wear. As the throttle slide moves up
and down while the machine is in opera—
tion, the needle is rubbing against the jet.
Eventually, these components will wear
enough to cause a noticeable rich run—
ning condition in the mid—throttle range.
If this occurs, both the needle andthe jet
should be replaced. If the components
are more than four years old, new ones
should be fitted before attempting to tune
the carburetor.
7. Carefully inspect the floats. If
brass floats are fitted, shake the float close
to your ear; listen for any gasoline
trapped inside. If the float assembly
leaks, or if any puncture is noted, replace
it; do not attempt repairs.
8. Inspect the tip of the float needle
and the needle seat for dirt or corrosion.
Check the needle tip for wear. If worn,
the needle should be replaced.
If there is any corrosion or deposits evi—
dent on the needle or needle seat, the de—
posits must be removed, or the parts re—
placed.
NOTE: Do not attempt to clean the
needle or needle seat by lapping one
against the other.
To check the efficiency of the float
needle valve, proceed as follows:
a. With the carburetor assembled
except for the float bowl, connect it to
its fuel line;
b. Place a number of dry rags be—
neath the carburetor, and hold it
upright (in its normal operating posi—
tion) with one hand;
c. With the other hand, gently raise
the float assembly until the float needle .
is seated. Have an assistant turn the
fuel petcock on;
d. If the needle and seat are in good
condition and forming a good seal, no
gasoline will flow out ofthe carburetor;
e. If a leak is noted, replace the
needle and seat.
CAUTION: While performing this
test, be sure that adequate precautions
are taken in the event of spillage.
The float level should be checked prior
to assembly. Refer to Chapter 3.
9. Check that the tapered portion of
the pilot screw is smooth and clean. Re—
place it if it is crushed or blunted.
10. Inspect the float bowl for a warped
gasket surface, or stress cracks (especially
around the screw holes).
11. Check the condition ofthe throttle
slide diaphragm. If ripped, the dia—
phragm and slide must be replaced.
Assembly
Assembly is basically the reverse ofthe
disassembly procedures, but note the fol—
lowing points:
1. Float bowl gaskets and jet O—rings