Yamaha Star XVS950A 2009, Service Manual

Page: 281 / 402

THROTTLE BODIES
6-10
f. Close the valve on the injector pressure
adapter.
g. Check that the specified air pressure is
held for about one seconds.
Pressure drops
→
Properly install or
replace the injector
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EAS26990
CHECKING THE THROTTLE BODIES
1. Check:
• Throttle bodies
Cracks/damage
→
Replace the throttle
bodies as a set.
2. Check:
• Fuel passages
Obstructions
→
Clean.
EAS5S71044
CHECKING AND CLEANING THE THROT-
TLE BODIES
TIP
Clean the throttle bodies only if they cannot be
synchronized using the bypass air screws.
Before cleaning the throttle bodies, check the
following items:
• Valve clearance
• Spark plugs
• Air filter element
• Throttle body joints
• Fuel hoses
• Exhaust system
• Breather hoses
WARNING
EWA5S71012
• If the throttle bodies are subjected to
strong shocks or dropped during clean-
ing, replace them as a set.
• Before removing the throttle bodies to
clean them, check the operation of the
throttle bodies. Refer to “FUEL INJEC-
TION SYSTEM” on page 7-27.
1. Check:
• Throttle bodies
Cracks/damage
→
Replace the throttle
bodies as a set.
2. Clean:
• Throttle bodies
ECA5S71015
• Observe the following precautions; other-
wise, the throttle bodies may not operate
properly.
• To clean the throttle body, remove the
throttle body from the vehicle.
• While cleaning, avoid injuring your fin-
gers working around the throttle valve.
• Do not remove the bolts unspecified in
the instructions (cause of malfunction).
• Do not open the throttle valves quickly.
• Do not subject the throttle bodies to
excessive force.
• Wash the throttle bodies in a petroleum-
based solvent.
• Do not use any caustic carburetor clean-
ing solution.
• Do not apply cleaning solvent directly to
any plastic parts, sensors, or seals.
• Do not directly push the throttle valves to
open them.
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a. Remove the throttle body from the vehicle.
b. Turn it over and put it on the workbench.
c. Plug the nipple for fuel.
d. Rotate the throttle valve and open. Keep it
open.
TIP
• Notice the following. If these are not followed,
there is possibility of a malfunction.
• Do not open suddenly.
• Do not apply too much load.
• Do not open in wrong direction.
• Do not press the butterfly valve directly and
open.
• Make sure not to contact the throttle adjust
screw.
e. Apply cleaner to a rug and clean to prevent
the removed foreign material from getting
into BAS path and space between shafts.
TIP
When removing foreign material, do not rub
inside of the bore with something that would
cause damages such as a wire brush.
f. After cleaning, air blow dry immediately
and check that there are no foreign materi-
als.
TIP
After cleaning the throttle body, adjust the syn-
chronization. If it does not reach the specified
value, replace the throttle body assy.
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