Yamaha YZ125 2009, Owner'S Service Manual

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4-12
CARBURETOR AND REED VALVE
CHECKING THE NEEDLE VALVE
1. Inspect:
• Needle valve "1"
• Valve seat "2"
Grooved wear "a"
→
Replace.
Dust "b"
→
Clean.
Always replace the needle valve and valve seat
as a set.
CHECKING THE THROTTLE VALVE
1. Check:
• Free movement
Stick
→
Repair or replace.
Insert the throttle valve "1" into the carburetor
body, and check for free movement.
CHECKING THE JET NEEDLE
1. Inspect:
• Jet needle "1"
Bends/wear
→
Replace.
• Clip groove
Free play exists/wear
→
Replace.
• Clip position
CHECKING THE FILTER
1. Inspect:
• Filter "1"
Damage
→
Replace.
Inspect the filter as it is assembled to the carbu-
retor. Do not remove the filter except when re-
placing it.
MEASURING AND ADJUSTING THE FUEL
LEVEL
1. Measure:
• Fuel level "a"
Out of specification
→
Adjust.
Fuel level Measurement and adjustment
steps:
a. Remove the drain plug.
b. Connect the fuel level gauge adapter "2" and
fuel level gauge "1" to the float chamber.
c. Hold the fuel level gauge vertically next to
the float chamber mating surface.
d. Measure the fuel level with the fuel level
gauge.
Standard clip position:
No.3 Groove
Fuel level:
9.5–10.5 mm (0.37–0.41 in)
Above the float chamber mating
surface
Fuel level gauge adapter:
YM-01470/90890-01470
Fuel level gauge:
YM-1312-A/90890-01312