Yamaha YZF-R125 Service Manual: 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:
Special tools
The following special tools are necessary for complete and accurate tune-up
and assembly. Use only
the appropriate special tools as this will help prevent damage caused by the use
of inappropriate tools
or improvised techniques. Special tools, part numbers or both may differ
depending on the ...
Assembling the crankcase
1. Thoroughly clean all the gasket mating surfaces
and crankcase mating surfaces.
2. Apply:
Sealant
(onto the crankcase mating surfaces)
NOTE:
Do not allow any sealant to come into contact
with the oil gallery.
3. Install:
Right crankcase
NOTE:
Turn the shift drum segment ...
Indicator and warning lights
Indicator and warning lights
Neutral indicator light""
Turn signal indicator light""
High beam indicator light""
Engine trouble warning light""
Coolant temperature warning light""
Turn signal indicator light""
This indicator light flashes when the
turn signal switch is pushed t ...