Troubleshooting Of Cooling System - Yamaha YZ125 2022 Owner's Service Manual

EAM30512

TROUBLESHOOTING OF COOLING SYSTEM

Symptom
Overheating
Noise from water pump
Possible cause
Carbon buildup in piston head and
combustion chamber
Clogged engine cooling water
passages
Damaged or leaking radiator
Faulty radiator cap
Clogged radiator fin
Bent or damaged radiator fin
Damaged or faulty water pump
Damaged hoses or pipes
Improperly connected hoses or
pipes
Clogged air filter element
Brake drags
Incorrect spark plug gap
Incorrect spark plug heat range
Contact between the water pump
housing cover and impeller
Worn water pump housing bearing
9-8
TROUBLESHOOTING
Actions
Clean the piston head and com-
bustion chamber.
Check and clean the engine cool-
ing water passages.
Replace the radiator.
Replace the radiator cap.
Clean the radiator fin.
Repair the radiator fin or replace
the radiator.
Replace the water pump.
Replace the hose or pipe.
Connect the hoses and pipes
properly.
Clean or replace the air filter ele-
ment.
Check the brake system and
repair or replace faulty parts as
necessary.
Adjust to the specified spark plug
gap.
Replace the spark plug with the
one of the specified type.
Disassemble the water pump and
replace faulty parts.
Replace the water pump housing
bearing.