PERIODIC MAINTENANCE AND ADJUSTMENT
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NOTICE:
Make sure that the air
filter element is properly seated
in the air filter case. The engine
should never be operated with-
out the air filter element in-
stalled, otherwise the piston(s)
and/or cylinder(s) may become
excessively worn.
[ECA10482]
10. Install the air filter case cover by in-
stalling the screws.
11. Install the panel.
EAU21281
Adjusting the carburetor
The carburetor is an important part of
the engine and requires very sophisti-
cated adjustment. Therefore, most car-
buretor adjustments should be left to a
Yamaha dealer, who has the neces-
sary professional knowledge and expe-
rience. The adjustment described in the
following section, however, may be ser-
viced by the owner as part of routine
maintenance.
NOTICE
ECA10551
The carburetor has been set and ex-
tensively tested at the Yamaha fac-
tory. Changing these settings
without sufficient technical knowl-
edge may result in poor perfor-
mance of or damage to the engine.
EAU21363
Adjusting the engine idling
speed
The engine idling speed must be
checked and, if necessary, adjusted as
follows at the intervals specified in the
periodic maintenance and lubrication
chart.
TIP
A diagnostic tachometer is needed to
make this adjustment.
1. Attach the tachometer to the spark
plug lead.
2. Start the engine and warm it up
for several minutes at 1000–2000
r/min while occasionally revving it
to 4000–5000 r/min.
TIP
The engine is warm when it quickly re-
sponds to the throttle.
3. Check the engine idling speed
and, if necessary, adjust it to spec-
ification by turning the throttle stop
screw. To increase the engine
idling speed, turn the screw in di-
rection (a). To decrease the en-
gine idling speed, turn the screw in
U53C23E0.book 13 ページ ２０１４年１月２２日 水曜日 午後２時７分
