Carburetor Adjustment; Idle Speed Adjustment - Yamaha XT250M 1999 Owner's Manual

PERIODIC MAINTENANCE AND MINOR REPAIR

Carburetor adjustment

The carburetor is a vital part of the
engine and requires very sophisti-
1
cated adjustment. Most adjust-
ments should be left to a Yamaha
2
dealer who has the professional
knowledge and experience to do
3
so. However, the following may be
serviced by the owner as part of
4
routine maintenance.
cC
5
The carburetor was set at the
Yamaha factory after many tests. If
6
the settings are changed, poor
engine performance and damage
7
may result.
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9
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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 approximate-
ly 1,000
Occasionally rev the engine to
EC000094
4,000 to
engine is warm when it quickly
responds to the throttle.
2. Set the idle to the specified
engine speed by adjusting the
throttle stop screw. Turn the
screw in
increase engine speed and in
direction b to decrease engine
speed.
Standard idle speed:
1,350 ~ 1,450 r/min
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1. Throttle stop screw
to 2,000 r/min.
NOTE:
5,000 r/min. The If the specified idle speed cannot
be obtained by performing the
above
Yamaha dealer.
a
direction to
6-13
a
b
1
adjustment, consult a