Carburetor Adjustment; Idle Speed Adjustment - Yamaha SR125 Owner's Manual

Carburetor adjustment

The carburetor is a vital part of the en-
gine and requires very sophisticated
adjustment. Most adjustments should
be left to a Yamaha dealer who has the
professional knowledge and experi-
ence to do so. However, the following
may be serviced by the owner as part
of routine maintenance.
CAUTION:
@
The carburetor was set at the
Yamaha factory after many tests. If
the settings are changed, poor en-
gine performance and damage may
result.
@
PERIODIC MAINTENANCE AND MINOR REPAIR
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Idle speed adjustment

NOTE:
@
A diagnostic tachometer must be used
for this procedure.
@
1. Attach the tachometer. Start the
engine and warm it up for a few
minutes at approximately 1,000 to
2,000 r/min. Occasionally rev the
engine to 4,000 to 5,000 r/min.
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The engine is warm when it quick-
ly responds to the throttle.
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1. Throttle stop screw
2. Set the idle to the specified engine
NOTE:
@
If the specified idle speed cannot be
obtained by performing the above ad-
justment, consult a Yamaha dealer.
@
6-11
speed by adjusting the throttle
stop screw. Turn the screw in di-
rection a to increase engine
speed and in direction b to de-
crease engine speed.
Standard idle speed:
1,300 ~ 1,400 r/min
6