2016 YAMAHA YZ250F coolant

CYLINDER HEAD
5-20
EAS1SM9213REMOVING THE CYLINDER HEAD
1. Remove:
• Intake camshaft
• Exhaust camshaft
Refer to “REMOVING THE CAMSHAFT” on
page 5-13.
2. Remove:
• Cylinder head nuts
• Cylinder head bolts
TIP
• Loosen the bolts in the proper sequence as
shown.
• Loosen each bolt 1/2 of a turn at a time. After
fully loosening all the bolts, remove them.
EAS1SM9214CHECKING THE TIMING CHAIN GUIDE (IN-
TAKE SIDE)
1. Check:
• Timing chain guide (intake side)
Damage/wear  Replace.
EAS1SM9215CHECKING THE CYLINDER HEAD
1. Eliminate:
• Combustion chamber carbon deposits
TIP
Use a rounded scraper, not a sharp instrument,
in order not to damage or scratch the spark
plug bore threads.2. Check:
• Cylinder head
Damage/scratches  Replace.
TIP
When replacing the cylinder head, replace also
the valve.
Refer to “CHECKING THE VALVE SEATS” on
page 5-25.
• Cylinder head coolant passages
Mineral deposits/rust  Eliminate.
3. Measure:
• Cylinder head warpage
Out of specification  Resurface the cylin-
der head.
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Place a straightedge and a thickness gauge
across the cylinder head.
b. Measure the warpage.
c. If the limit is exceeded, resurface the cylin-
der head as follows.
d. Place a 400–600 grit wet sandpaper on a
surface plate, and resurface the cylinder
head using a figure-eight sanding pattern.
TIP
To ensure an even surface, turn the cylinder
head several times.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
61
2
35
4 x2 x4FWD
Warpage limit
0.05 mm (0.0020 in)

CLUTCH
5-37
Removing the right crankcase cover
Order Part name Q’ty Remarks
Right engine guard Refer to “ENGINE REMOVAL” on page 5-1.
Engine oilDrain.
Refer to “CHANGING THE ENGINE OIL” on
page 3-15.
CoolantDrain.
Refer to “CHANGING THE COOLANT” on
page 3-8.
Brake pedal Refer to “ENGINE REMOVAL” on page 5-1.
Clutch cover Refer to “CLUTCH” on page 5-35.
1 Oil filter element cover 1
2 Oil filter element 1
3 Radiator pipe 2 1
4 Kickstarter lever 1
5 Right crankcase cover 1
6 Gaskets 1
7 Dowel pin 2
8Collar 1
For installation, reverse the removal proce-
dure.
T.R.
LS
New
New
67
2
5
4
1
7 8
New
3
LS
New
New
LS
NewNew
LT
LS

RADIATOR
6-1
EAS1SM9293
TIP
This section is intended for those who have basic knowledge and skill concerning the servicing of
Yamaha motorcycles (e.g., Yamaha dealers, service engineers, etc.). Those who have little knowl-
edge and skill concerning servicing are requested not to undertake inspection, adjustment, disas-
sembly, or reassembly only by reference to this manual. It may lead to servicing trouble and
mechanical damage.
EAS1SM9294
RADIATOR
Removing the radiator
Order Part name Q’ty Remarks
CoolantDrain.
Refer to “CHANGING THE COOLANT” on
page 3-8.
Seat Refer to “GENERAL CHASSIS” on page 4-1.
Side cover (left/right) Refer to “GENERAL CHASSIS” on page 4-1.
Air scoop (left / right) Refer to “GENERAL CHASSIS” on page 4-1.
Fuel tank Refer to “FUEL TANK” on page 7-1.
Air filter case Refer to “THROTTLE BODY” on page 7-5.
1 Radiator guard 2
2 Radiator hose clamp 8 Loosen.
11
12
New
New
New
LS
LS

RADIATOR
6-2
3 Right radiator 1
4 Radiator hose 2 1
5 Radiator hose 3 1
6 Radiator hose 4 1
7 Radiator pipe 2 1
8 Radiator breather hose 1
9 Left radiator 1
10 Radiator hose 1 1
11 Radiator pipe 1 1
12 Coolant temperature sensor 1
For installation, reverse the removal proce-
dure.
Removing the radiator
Order Part name Q’ty Remarks
11
12
New
New
New
LS
LS

RADIATOR
6-3
EAS1SM9295HANDLING NOTEEWA
WARNING
If coolant seems hot, do not remove the ra-
diator cap.
EAS1SM9296CHECKING THE RADIATOR
1. Check:
• Radiator fins “1”
Obstructions  Clean.
Apply compressed air to the rear of the radi-
ator.
Damage  Repair or replace.
TIP
Correct any flattened fins with a thin, flat-head
screwdriver.
2. Check:
• Radiator hoses
• Radiator pipes
Crack/damage  Replace.

WATER PUMP
6-4
EAS1SM9297
WATER PUMP
Removing the water pump
Order Part name Q’ty Remarks
CoolantDrain.
Refer to “CHANGING THE COOLANT” on
page 3-8.
Engine oilDrain.
Refer to “CHANGING THE ENGINE OIL” on
page 3-15.
Right crankcase cover Refer to “CLUTCH” on page 5-35.
1 Water pump housing 1
2 Dowel pin 2
3Gasket 1
4Washer 2
5Collar 1
6Gear 1
7Pin 1
8 Impeller shaft assembly 1
9 Oil seal 1
9
8
2
2
3
1
10
6
7
5
4
4
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
10 Nm (1.0 mkgf, 7.2 ftIbf)T.R.
New
New
New
E
11
New
E
LS
LS

WATER PUMP
6-6
EAS1SM9298REMOVING THE OIL SEAL
TIP
• Remove the oil seal when the coolant level
changes frequently more than usual, coolant
has discolored, or engine oil has become
milky.
• Do not use the removed oil seal.
1. Remove:
• Oil seals “1”
EAS1SM9299CHECKING THE WATER PUMP
1. Check:
• Water pump housing cover
• Impeller shaft
Cracks/damage/wear  Replace.
EAS1SM9300CHECKING THE BEARING
1. Check:
• Bearing
Rotate the inner race with your finger.
Rough spot/seizure  Replace.
EAS1SM9301INSTALLING THE OIL SEAL
1. Install:
• Oil seals “1”
TIP
• Apply the lithium-soap-based grease on the
oil seal lip.
• Install the oil seal with its manufacture’s
marks or numbers facing the right crankcase
cover “2”.2. Install:
• Bearing “1”
TIP
Install the bearing by pressing its outer race
parallel.
EAS1SM9302ASSEMBLING THE WATER PUMP
1. Install:
• Impeller shaft assembly “1”
• Washer “2”
•Pin “3”
• Gear “4”
• Collar “5”
• Circlip “6”
TIP
• Take care so that the oil seal lip is not dam-
aged or the spring does not slip off its posi-
tion.
• When installing the impeller shaft, apply the
engine oil to the oil seal lip, the bearing, and
the impeller shaft.
1 1
New
1 1New
New
LS
LS2
New
1
2
52346
New
E

WATER PUMP
6-7
2. Install:
• Dowel pin “1”
• Gasket “2”
3. Install:
• Water pump housing “1”
• Water pump housing bolt “2”
• Washer “3”
• Coolant drain bolt “4”Water pump housing bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Coolant drain bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
New
21
1New
T R..
New
T R..
2
2
43 1
New