Yamaha YZ 2023 Series, Owner'S Service Manual

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TROUBLESHOOTING
9-7
EAM30512
TROUBLESHOOTING OF COOLING SYSTEM
Symptom Possible cause Actions
Overheating
Carbon buildup in piston head and
combustion chamber
Clean the piston head and com-
bustion chamber.
Clogged engine cooling water
passages
Check and clean the engine cool-
ing water passages.
Incorrect oil level
Adjust the oil level to the specified
level.
Incorrect oil viscosity
Change to recommended engine
oil.
Inferior oil quality
Change to recommended engine
oil.
Low coolant level
Add recommended coolant to the
specified level.
Damaged or leaking radiator Replace the radiator.
Faulty radiator cap Replace the radiator cap.
Clogged radiator fin Clean the radiator fin.
Bent or damaged radiator fin
Repair the radiator fin or replace
the radiator.
Damaged or faulty water pump Replace the water pump.
Damaged hoses or pipes Replace the hose or pipe.
Improperly connected hoses or
pipes
Connect the hoses and pipes
properly.
Damaged throttle body joint Replace the throttle body joint.
Loose throttle body joint
Tighten the throttle body joint bolts
to the specified torque.
Clogged air filter element
Clean or replace the air filter ele-
ment.
Brake drags
Check the brake system and
repair or replace faulty parts as
necessary.
Incorrect spark plug gap
Adjust to the specified spark plug
gap.
Incorrect spark plug heat range
Replace the spark plug with the
one of the specified type.
Faulty ECU Replace the ECU.
Noise from water pump
Contact between the water pump
housing cover and impeller
Disassemble the water pump and
replace faulty parts.
Worn water pump housing bearing Replace the water pump housing
bearing.