Yamaha YZ125X 2023, Owner'S Manual

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TROUBLESHOOTING
7-3
Incorrect mid-high speed
—
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.
Failed air induction system
Check the air induction system.
Repair or replace faulty parts.
Clogged vacuum hose Clean the vacuum hose.
Cracks and damage in vacuum
hose
Replace the vacuum hose.
Damaged carburetor joint Replace the carburetor joint.
Loose carburetor joint
Tighten the carburetor joint bolts
to the specified torque.
Clogged air filter element
Clean or replace the air filter ele-
ment.
Symptom Possible cause Actions
Spark plug does not produce a
spark
Incorrect spark plug gap Adjust the spark plug gap.
Worn or damaged spark plug Replace the spark plug.
Defective spark plug cap Replace the spark plug cap.
Defective ignition coil Replace the ignition coil.
CDI unit failure Replace the CDI unit.
Fuel not supplied
Fuel leakage
Check the fuel passage. Repair or
replace as necessary.
Clogged carburetor fuel passage Clean the carburetor.
Clogged needle valve or needle
valve seat
Clean the needle valve or needle
valve seat.
Damaged float Replace the float.
Symptom Possible cause Actions