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:
Checking the front brake lever free play
Checking the front brake lever free play
Brake lever free play
The brake lever free play should measure
2.0-5.0 mm (0.08-0.20 in) as
shown. Periodically check the brake lever
free play and, if necessary, have a
Yamaha dealer check the brake system.
WARNING
An incorrect brake le ...
Installing the front wheel (disc)
1. Install:
Front brake disc
NOTE:
Be sure to install the front brake disc with the
arrow mark "a" on the disc facing out.
Tighten the brake disc bolts in stages and in a
crisscross pattern.
2. Check:
Front brake disc
Refer to "CHECKING THE FRONT BRAKE
DISC" on page 4 ...
Installing the throttle body
1. Install:
Throttle body joint clamps
NOTE:
Align the projections "a" on the throttle body joint
with the slot "b" in each throttle body joint clamp.
2. Install:
Throttle body joint
NOTE:
Align the projection "a" on the throttle body joint
with the slot "b" in the intake mani ...