Yamaha YZF-R125 Service Manual: Overheating

Yamaha YZF-R125 Service Manual / Troubleshooting / Overheating

Engine

1. Clogged coolant passages

Cylinder head and piston
Heavy carbon buildup

2. Engine oil

Incorrect oil level
Incorrect oil viscosity
Inferior oil quality

Cooling system

1. Coolant

Low coolant level

2. Radiator

Damaged or leaking radiator
Faulty radiator cap
Bent or damaged radiator fin

3. Water pump

Damaged or faulty water pump
Thermostat
Thermostat stays closed
Hose(s) and pipe(s)
Damaged hose
Improperly connected hose
Damaged pipe
Improperly connected pipe

Fuel system

1. Throttle body

Damaged or loose throttle body joint

2. Air filter

Clogged air filter element

Chassis

1. Brake(s)

Dragging brake

Electrical system

1. Spark plug

Incorrect spark plug gap
Incorrect spark plug heat range

2. Ignition system

Faulty ECU

Overcooling

Cooling system

1. Thermostat

Thermostat stays open

Faulty clutch

Clutch slips 1. Clutch Improperly assembled clutch Improperly adjusted clutch cable Loose or fatigued clutch spring Worn friction plate Worn clutch plate 2. Engine oil Incorrect oi ...

Poor braking performance

- Worn brake pad - Worn brake disc - Air in hydraulic brake system - Leaking brake fluid - Faulty brake caliper kit - Faulty brake caliper seal - Loose union bolt - Damaged brake hose - Oil or ...

Other materials:

Multi-function display
Multi-function display Multi-function display "RESET/SELECT" button WARNING Be sure to stop the vehicle before making any setting changes to the multi-function display. Changing settings while riding can distract the operator and increase the risk of an accident. The multi- ...

Checking the radiator fan motor
1. Check: Radiator fan motor Faulty/rough movement → Replace. a. Disconnect the radiator fan motor coupler from the wire harness. b. Connect the battery (DC 12 V) as shown. Positive tester probe → blue "1" Negative tester probe → black "2" c. Measure ...

Checking the steering head
1. Wash: Bearings Bearing races 2. Check: Bearings Bearing races Damage/pitting →Replace. 3. Replace: Bearings Bearing races a. Remove the bearing races from the steering head pipe with a long rod "1" and hammer. b. Remove the bearing race from the lower bracket ...