PERIODIC MAINTENANCE AND ADJUSTMENT
7-16
7
EAU21280
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
serviced by the owner as part of routine
maintenance.
ECA10550
NOTICE
_
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.
_
EAUU0320
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.
The engine should be warm before
making this adjustment.
TIP
_
●
The engine is warm when it quick-
ly responds to the throttle.
●
A diagnostic tachometer is needed
to make this adjustment.
_
1. Open the seat. (See page 4-9 for
seat opening and closing proce-
dures.)
2. Remove panel B. (See page 7-6
for panel removal and installation
procedures.)
3. Attach the tachometer to the spark
plug lead.
4. Check the engine idling speed
and, if necessary, adjust it to spec-
ification as follows.
5. Remove the rubber cap and insert
a Phillips screwdriver into the
throttle stop screw hole.
6. To increase the engine idling
speed, turn the screw in direction
(a). To decrease the engine idling
speed, turn the screw in direction
(b).
TIP
_
If the specified idling speed cannot be
obtained as described above, have a
Yamaha dealer make the adjustment.
_
7. Install the panel and close the
seat.
1. Throttle stop screw
Engine idling speed:
1400–1600 r/min
1
1
(b)
(b)
(b)
(a)
(a)
(a)
ZAUU0397
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