fuel YAMAHA YZ250F 2014 Owner's Manual

3
PERIODIC CHECKS AND ADJUSTMENTS
MAINTENANCE INTERVALS.......................................................................... 3-1
MAINTENANCE INTERVALS .................................................................... 3-1
PRE-OPERATION INSPECTION AND MAINTENANCE................................. 3-7
GENERAL INSPECTION AND MAINTENANCE........................................ 3-7
ENGINE............................................................................................................ 3-8
CHECKING THE COOLANT LEVEL .......................................................... 3-8
CHECKING THE COOLING SYSTEM ....................................................... 3-8
CHANGING THE COOLANT...................................................................... 3-8
CHECKING THE RADIATOR CAP ............................................................ 3-9
CHECKING THE RADIATOR CAP OPENING PRESSURE ...................... 3-9
CHECKING THE COOLANT CIRCULATORY SYSTEM FOR LEAKS .... 3-10
ADJUSTING THE CLUTCH LEVER POSITION ...................................... 3-10
ADJUSTING THE CLUTCH LEVER FREE PLAY .................................... 3-10
ADJUSTING THE THROTTLE GRIP FREE PLAY .................................. 3-11
LUBRICATING THE THROTTLE CABLE ................................................ 3-12
CLEANING THE AIR FILTER ELEMENT................................................. 3-12
CHECKING THE THROTTLE BODY JOINT ............................................ 3-13
CHECKING THE BREATHER HOSES .................................................... 3-13
CHECKING THE EXHAUST SYSTEM..................................................... 3-13
CHECKING THE FUEL LINE ................................................................... 3-14
CHECKING THE ENGINE OIL LEVEL..................................................... 3-14
CHANGING THE ENGINE OIL ................................................................ 3-15
ADJUSTING THE ENGINE IDLING SPEED ............................................ 3-16
ADJUSTING THE VALVE CLEARANCE ................................................. 3-17
CHASSIS........................................................................................................ 3-21
BLEEDING THE BRAKE SYSTEM .......................................................... 3-21
CHECKING THE BRAKE HOSE .............................................................. 3-22
ADJUSTING THE FRONT BRAKE .......................................................... 3-22
ADJUSTING THE REAR BRAKE ............................................................. 3-23
CHECKING THE FRONT BRAKE PADS ................................................. 3-23
CHECKING THE REAR BRAKE PADS ................................................... 3-25
CHECKING THE REAR BRAKE PAD INSULATOR ................................ 3-26
CHECKING THE BRAKE FLUID LEVEL.................................................. 3-26
ADJUSTING THE DRIVE CHAIN SLACK ................................................ 3-27
CHECKING THE FRONT FORK LEGS ................................................... 3-28
CHECKING THE FRONT FORK PROTECTOR GUIDE .......................... 3-28
CLEANING THE FRONT FORK OIL SEAL AND DUST SEAL ................ 3-28
AIR BLEEDING FROM FRONT FORK .................................................... 3-28
ADJUSTING THE FRONT FORK LEGS .................................................. 3-29
CHECKING THE SWINGARM OPERATION ........................................... 3-30
CHECKING THE REAR SUSPENSION ................................................... 3-30
ADJUSTING THE REAR SHOCK ABSORBER ASSEMBLY ................... 3-30
CHECKING THE TIRES ........................................................................... 3-32
CHECKING AND TIGHTENING THE SPOKES ....................................... 3-32
CHECKING THE WHEELS ...................................................................... 3-33

MAINTENANCE INTERVALS
3-4
FUEL TANK, FUEL
PUMP
Inspect
FUEL HOSE
Inspect
Replace Every four years
FRONT FORK LEG
(S)
Clean Dust seal
Inspect and adjust
Replace oil
Replace oil seal
Clean and grease
oil seals and dust
sealsLithium soap base grease
PROTECTOR
GUIDE
Replace
REAR SHOCK AB-
SORBER
Inspect and adjust
Lubricate(After
rain
ride)Grease pillow balls and bear-
ings.
Retighten Check for tightening torques.
BRAKE(S)
Adjust lever posi-
tion and pedal
height
Lubricate pivot
point
Check brake disc
surface
Check fluid level
and leakage
Retighten brake
disc bolts, caliper
bolts, master cylin-
der bolts and union
boltsCheck for tightening torques.
Replace padsITEMAfter
break-
inEvery
race
(about
2.5
hours)Every
third
(about
7.5
hours)Every
fifth
(about
12.5
hours)As re-
quiredRemarks

PRE-OPERATION INSPECTION AND MAINTENANCE
3-7
EAS1SM1067
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
EAS1SM1068GENERAL INSPECTION AND MAINTENANCE
TIP
Perform usual maintenance enough so that, in the race course, a confirmation of that and simple set-
ting adjustments may only be left, in order to get enough time to use effectively.ITEM inspect Page
CoolantCheck that coolant is filled up to the radiator cap.
Check the cooling system for leakage.3-8 – 10
FuelCheck that a fresh gasoline is filled in the fuel tank.
Check the fuel line for leakage.1-22
Engine oilCheck that the oil level is correct. Check the crank-
case and oil line for leakage.3-14 – 16
Gear shifter and clutchCheck that gears can be shifted correctly in order and
that the clutch operates smoothly.3-10 – 11
Throttle grip/HousingCheck that the throttle grip operation and free play
are correctly adjusted. Lubricate the throttle grip and
housing, if necessary.3-11 – 12
BrakesCheck the play of front brake and effect of front and
rear brake.3-21 – 27
Drive chainCheck drive chain slack and alignment. Check that
the drive chain is lubricated properly.3-27
4-64 – 65
WheelsCheck for excessive wear and tire pressure. Check
for loose spokes and have no excessive play.3-33
SteeringCheck that the handlebar can be turned smoothly and
have no excessive play.3-33 – 34
Front forks and rear
shock absorberCheck that they operate smoothly and there is no oil
leakage.3-28 – 32
Cables (wires)Check that the clutch and throttle cables move
smoothly. Check that they are not caught when the
handlebars are turned or when the front forks travel
up and down.—
Exhaust pipeCheck that the exhaust pipe is tightly mounted and
has no cracks.3-13 – 14
Rear wheel sprocketCheck that the rear wheel sprocket tightening bolt is
not loose.4-8 – 9
Lubrication Check for smooth operation. Lubricate if necessary. 3-12, 3-34
Bolts and nutsCheck the chassis and engine for loose bolts and
nuts.1-25 – 26
Lead connectorsCheck that the AC magneto, ECU and ignition coil are
connected tightly.1-12 – 14
SettingsIs the machine set suitably for the condition of the rac-
ing course and weather or by taking into account the
results of test runs before racing? Are inspection and
maintenance completely done?10-1 – 8

ENGINE
3-12
EAS1SM1079LUBRICATING THE THROTTLE CABLE
1. Remove:• Cover (throttle cable cap) “1”
• Cover (grip cap) “2”
• Throttle grip cap “3”
2. Lubricate: • Throttle cable end “a”
3. Install: • Throttle grip cap
• Screw (throttle grip cap)
4. Install: • Cover (grip cap)
• Cover (throttle cable cap)
EWA
WARNING
Check that the throttle grip moves smooth-
ly. If this does not move smoothly, correct
the installed positions.
EAS1SM1080CLEANING THE AIR FILTER ELEMENT
1. Remove:• Fuel tank cap cover “1”
Refer to “FUEL TANK CAP” on page 1-21.
• Air filter case cover “2” 2. Remove:
• Air filter mounting bolt “1”
• Air filter element “2”
• Air filter guide “3” (from the air filter element)
3. Wash: • Air filter element
EWA
WARNING
Do not use gasoline or organic (acid/alka-
line) volatile oil for washing.
TIP
After washing the element with air filter cleaner
or kerosene, squeeze and dry it completely.
ECA33DD016
NOTICE
Do not twist the element when squeezing
the element.
Recommended lubricant
Lithium-soap-based grease
Screw (throttle grip cap) 3.8 Nm (0.38 m·kgf, 2.8 ft·lbf)
T R..
1
2
13
2

ENGINE
3-13
4. Check:
• Air filter element
Damage  Replace.
5. Foam-air-filter oil or equivalent oil to the ele-
ment
TIP
Squeeze out the excess oil. Element should be
wet but not dripping.
6. Install:
• Air filter guide “1” (to the air filter element)
• Air filter element “2”
• Air filter mounting bolt “3”
7. Install:
• Air filter case cover “1”
• Air filter case cover mounting bolt
TIP
Align the air filter case cover groove “a” with the
air filter case edge “b”.
8. Install:
• Fuel tank cap cover
EAS1SM1081CHECKING THE THROTTLE BODY JOINT
1. Check:
• Throttle body joint “1”
Refer to “CHECKING THE THROTTLE
BODY JOINT” on page 7-8.
EAS1SM1082CHECKING THE BREATHER HOSES
1. Check:
• Breather hose “1”
Crack/damage  Replace.
Loose connection  Connect properly.
ECA14920
NOTICE
Make sure that the breather hoses are rout-
ed correctly.
EAS1SM1083CHECKING THE EXHAUST SYSTEM
1. Remove:
• Exhaust pipe protector
2. Check:
• Exhaust pipe 1
• Exhaust pipe 2
• Silencer
Crack/damage  Replace.
Refer to “ENGINE REMOVAL” on page 5-1.
• Exhaust gas
Leaks  Replace the gasket.
Refer to “ENGINE REMOVAL” on page 5-1.
3. Check:
• Tightening torques Oil application quantify
50 g
Air filter mounting bolt
2 Nm (0.2 m·kgf, 1.4 ft·lbf)
Air filter case cover mounting bolt
6 Nm (0.6 m·kgf, 4.3 ft·lbf)
T R..
31
2
T R..
a
b 1
Exhaust pipe bolt 1 and nut “1”
20 Nm (2.0 m·kgf, 14 ft·lbf)
Exhaust pipe 1 and exhaust pipe
2 bolt “2”
12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Exhaust pipe 2 and silencer bolt
“3”
12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Silencer and silencer bracket bolt
“4”
30 Nm (3.0 m·kgf, 22 ft·lbf)
1
T R..

ENGINE
3-14
4. Install:
• Exhaust pipe protector
EAS1SM1084CHECKING THE FUEL LINE
1. Remove:
• Seat
• Side cover (left/right)
• Air scoop (left/right)
Refer to “GENERAL CHASSIS” on page 4-
1.
• Fuel tank
Refer to “FUEL TANK” on page 7-1.
2. Check:
• Fuel hose “1”
Crack/damage  Replace.
Loose connection  Connect properly.3. Install:
• Fuel tank
Refer to “FUEL TANK” on page 7-1.
• Air scoop (left/right)
• Seat
• Side cover (left/right)
Refer to “GENERAL CHASSIS” on page 4-
1.
EAS1SM1085CHECKING THE ENGINE OIL LEVEL
1. Stand the vehicle upright on a level surface.
2. Start the engine, warm this up for 2–3 min-
utes, and then stop the engine and wait
about 5 minute.
3. Check:
• Oil level
The engine oil level should be between the
minimum level mark “a” and maximum level
mark “b”.
Below the minimum level mark  Add the
recommended engine oil to the proper level.
ECA33DD018
NOTICE
• Since engine oil also lubricates the clutch,
the wrong oil types or additives could
cause clutch slippage. Therefore, do not
add any chemical additives.
• Do not allow foreign material to enter the
crankcase. Exhaust pipe protector screw
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
LOCTITE®
2
1
4
3
T R..
1
Recommended brand
YAMALUBE
Recommended engine oil type
SAE10W-30, SAE10W-40,
SAE10W-50, SAE15W-40,
SAE20W-40 or SAE20W-50
Recommended engine oil grade
API service SG type or higher,
JASO standard MA
a b

ENGINE
3-16
7. Pour the specified amount of engine oil into
the oil filler cap hole.
8. Install:
• Oil filler cap
9. Check:
• Oil level
Refer to “CHECKING THE ENGINE OIL
LEVEL” on page 3-14.
10.Check:
• Engine oil pressure
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Slightly loosen the oil pressure check bolt
“1”.
EWA
WARNING
When the engine is started with the check
bolt removed, oil will spout; therefore, al-
ways loosen it before the checkup.
Start the engine and keep it idling until oil
starts to seep from the oil pressure check
bolt.
EWA
WARNING
Always keep the engine idling speed during
the checkup without increasing the engine
speed.
ECA
NOTICE
If no engine oil seeps out after one minute,
immediately turn the engine off so it will not
seize.
b. If no engine oil seeps out, check the engine
oil for leaks, and the engine oil passage and
the oil pump for damage.
c. Check the oil pressure again.
d. Tighten the oil pressure check bolt.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS1SM1087ADJUSTING THE ENGINE IDLING SPEED
TIP
• Because the air pressure is lower at high alti-
tudes, the air-fuel mixture will become richer.
If the idling speed is low, turn the starter knob/
idle screw a few clicks counterclockwise to in-
crease the speed before the adjustment.
• Before adjusting the engine idling speed,
make sure that the air filter element is not
clogged, the engine compression is proper,
and the throttle grip free play is proper.
• Adjust the engine idling speed with the starter
knob/idle screw pushed in completely.
1. Start the engine, and warm this up until the
oil has reached the specified temperature.
2. Attach the pocket tester with temperature
probe “1” to the oil drain bolt. Engine oil quantity
Without oil filter element replace-
ment
0.71 L (0.75 US qt, 0.62 Imp.qt)
With oil filter element replace-
ment
0.73 L (0.77 US qt, 0.64 Imp.qt)
Quantity (disassembled)
0.90 L (0.95 US qt, 0.79 Imp.qt)
1
Oil pressure check bolt
10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil temperature
55–65 °C (131–149 °F)
T R..
1

ENGINE
3-17
3. Install:
• Digital tachometer
TIP
Get the high tension cord “1” of the ignition coil
pinched in the detector “a” of the digital tachom-
eter.
4. Measure:
• Engine idling speed
Out of specification  Regulate.
5. Adjust:
• Engine idling speed
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Turn the starter knob/idle screw “1” in the di-
rection of “a” or “b” to make an adjustment.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
EAS1SM1088
ADJUSTING THE VALVE CLEARANCE
TIP
• This section is intended for those who have
basic knowledge and skill concerning the ser-
vicing of Yamaha motorcycles (e.g., Yamaha
dealers, service engineers, etc.). Those who
have little knowledge and skill concerning ser-
vicing are requested not to undertake inspec-
tion, adjustment, disassembly, or reassembly
only by reference to this manual. It may lead
to servicing trouble and mechanical damage.
• Make sure that the valve clearance is
checked or adjusted while the engine is cold
(at room temperature).
• While the valve clearance is checked or ad-
justed, make sure that the piston is positioned
in the top dead center (TDC).
1. Remove:
• Seat
• Side cover (left/right)
• Air scoop (left/right)
Refer to “GENERAL CHASSIS” on page 4-
1.
• Fuel tank
Refer to “FUEL TANK” on page 7-1.
•ECU
2. Remove:
• Spark plug
• Cylinder head cover
Refer to “CAMSHAFT” on page 5-11.
3. Remove:
• Timing mark accessing screw “1”
• Crankshaft end accessing screw “2”
• O-ring
4. Check:
• Valve clearance
Out of specification  Regulate. Digital tachometer
90890-06760
YU-39951-B
Engine idling speed
1900–2100 r/min
Direction “a” Engine idling speed  De-
creases.
Direction “b” Engine idling speed  In-
creases.
1 1
a a
1 b
a
Valve clearance (cold)
Intake
0.12–0.19 mm (0.0047–0.0075 in)
Exhaust
0.17–0.24 mm (0.0067–0.0094 in)
1
2

ELECTRICAL SYSTEM
3-35
EAS1SM1114
ELECTRICAL SYSTEM
EAS1SM1115CHECKING THE SPARK PLUG
1. Remove:
• Seat
• Air scoop (left/right)
Refer to “GENERAL CHASSIS” on page 4-
1.
• Fuel tank “1”
Refer to “FUEL TANK” on page 7-1.
ECA1DX1001
NOTICE
Do not use too much force to pull the hose.
TIP
Remove the fuel tank, turn this 180 ° clockwise,
and put it in the frame “2” as shown.
2. Remove:
• Spark plug cap
• Spark plug
Refer to “CAMSHAFT” on page 5-11.
ECA13330
NOTICE
In order not to allow the dirt accumulated
around the spark plug to drop from the
spark plug hole into the cylinder, clean it be-
fore removing the spark plug.
3. Check:
• Spark plug type
Wrong type  Replace.
4. Check:
• Electrode
Damage/wear  Replace the spark plug.
• Insulator
Abnormal color  Replace the spark plug.
Normal color is medium-to-light tan.5. Clean:
• Spark plug
(with a spark plug cleaner or a wire brush)
6. Measure:
• Spark plug gap “a”
Out of specification  Adjust the spark plug
gap.
7. Install:
• Spark plug
TIP
Before installing the spark plug, clean the spark
plug and gasket surface.
8. Install:
• Spark plug cap
• Fuel tank
• Air scoop (left/right)
• Seat
• Side cover (left/right)
Refer to “GENERAL CHASSIS” on page 4-
1.
EAS1SM1116CHECKING THE IGNITION TIMING
1. Remove:
• Timing mark accessing screw “1”
Manufacturer/model
NGK/LMAR8G
1
1
2
Spark plug gap
0.7–0.8 mm (0.028–0.031 in)
Spark plug
13 Nm (1.3 m·kgf, 9.4 ft·lbf)
T R..
1

GENERAL CHASSIS
4-2
EAS1SM1119REMOVING THE LEFT SIDE COVER
1. Remove:• Bolt (side cover)
• Side cover “1”
TIP
Draw the left side cover “1” backward to re-
move it because its projection “a” is inserted in
the rear frame.
EAS1SM1120REMOVING THE SEAT
TIP
The fuel tank cap cover and the seat are cou-
pled with each other with a plastic band.
When removing the seat, always remove the
fuel tank cap cover beforehand.
1. Remove:• Fuel tank cap cover “1”
Refer to “FUEL TANK CAP” on page 1-21.
2. Remove: • Seat “1”
EAS1SM1121REMOVING THE NUMBER PLATE
1. Remove:• Bolt (number plate)
• Number plate “1”
TIP
• The projection “a” is inserted into the band of the number plate. Pull the band off the projec-
tion before removal.
• Remove the clutch cable “2” from the cable guide “b” on the number plate.
• The projection “c” on the lower bracket is in- serted into the number plate. Remove the
number plate by pulling it off the projection.
1
a
1
1
1