Yamaha YZ250N Owner's Service Manual page 230

CARBURETOR AND REED VALVE
4-10
EC464000
INSPECTION
EC464130
Carburetor
1. Inspect:
9Carburetor body
Contamination
NOTE:
9Use a petroleum based solvent for cleaning.
Blow out all passages and jets with com-
pressed air.
9Never use a wire.
2. Inspect:
9Main jet 1
9Pilot jet 2
9Power jet 3
Contamination
NOTE:
9Use a petroleum based solvent for cleaning.
Blow out all passages and jets with com-
pressed air.
9Never use a wire.
EC464210
Needle valve
1. Inspect:
9Needle valve 1
9Valve seat 2
Grooved wear a
Dust b
Clean.
EC464310
Throttle valve
1. Check:
9Free movement
Stick Repair or replace.
NOTE:
Insert the throttle valve 2 into the carburetor
body while pulling up the lever 1, and check for
free movement.
ENG
Clean.
Clean.
Replace.