Yamaha YZ125X 2023, Owner'S Manual

Page: 115 / 146

TROUBLESHOOTING
7-4
—
Water or foreign material in fuel,
degraded fuel
Change fuel.
Clogged carburetor air passage Clean the carburetor.
Incorrectly adjusted throttle cable Adjust the throttle grip free play.
Improperly synchronized carbure-
tors
Adjust synchronization of carbure-
tors.
Incorrectly adjusted pilot screw Adjust the pilot screw.
Incorrectly adjusted pilot air screw Adjust the pilot air screw.
Clogged pilot jet Clean the pilot jet.
Loose pilot jet
Tighten the pilot jet to the specified
torque.
Clogged main nozzle Clean the main nozzle.
Loose main nozzle
Tighten the main nozzle to the
specified torque.
Clogged main jet Clean the main jet.
Loose main jet
Tighten the main jet to the speci-
fied torque.
Bent, damaged, or worn jet needle Replace the jet needle.
Cracks or damage in the piston
valve diaphragm
Replace the piston valve dia-
phragm.
Problem with piston valve move-
ment (movement is not smooth)
Replace the piston valve.
Damaged or worn needle valve
seat
Replace the needle valve seat.
Loose needle valve seat
Tighten the needle valve seat to
the specified torque.
Damaged or worn needle valve Replace the needle valve.
Incorrect fuel level
Adjust the fuel level to the proper
level.
Bent, worn, or damaged starter
plunger
Replace the starter plunger.
Incorrectly adjusted starter cable Adjust the starter cable.
Clogged or damaged carburetor
breather hose
Clean, repair, or replace the car-
buretor breather hose.
Incorrect throttle position sensor
angle
Adjust the throttle position sensor
angle.
Symptom Possible cause Actions