lock YAMAHA YZ250F 2014 Owners Manual

EAS1SM1007
SYMBOLS
The following symbols are used in this manual for easier understanding.
TIP
The following symbols are not relevant to every vehicle.
SYMBOL DEFINITION SYMBOL DEFINITION
Serviceable with engine mounted Gear oil
Filling fluid Molybdenum disulfide oil
Lubricant Brake fluid
Special tool Wheel bearing grease
Tightening torque Lithium-soap-based grease
Wear limit, clearance Molybdenum disulfide grease
Engine speed Silicone grease
Electrical data Locking agent (LOCTITE®)
Engine oil Replace the part with a new one.
G
M
BF
B
T R..
LS
M
S
LT
E
New

1
GENERAL INFORMATION
LOCATION OF IMPORTANT LABELS............................................................ 1-1
DESCRIPTION .................................................................................................. 1-4
IDENTIFICATION ............................................................................................. 1-5
VEHICLE IDENTIFICATION NUMBER ...................................................... 1-5
ENGINE SERIAL NUMBER ....................................................................... 1-5
MODEL LABEL........................................................................................... 1-5
FEATURES ....................................................................................................... 1-6
OUTLINE OF THE FI SYST EM .................................................................. 1-6
FI SYSTEM....................................... .......................................................... 1-7
INCLUDED PARTS .......................................................................................... 1-8
SIDESTAND ............................................................................................... 1-8
SPARK PLUG WRENCH ........................................................................... 1-8
NIPPLE WRENCH...................................................................................... 1-8
HANDLEBAR PROTECTOR .. .................................................................... 1-8
FUEL HOSE JOINT COVER ...................................................................... 1-8
COUPLER FOR CONNECTING OPTIONAL PART................................... 1-8
IMPORTANT INFORMATION ........................................................................ 1-10
PREPARATION FOR REMOVAL A ND DISASSEMBLY.......................... 1-10
REPLACEMENT PARTS.......................................................................... 1-10
GASKETS, OIL SEALS AND O-RINGS ................................................... 1-11
LOCK WASHERS/PLATES AND COTTER PINS .................................... 1-11
BEARINGS AND OIL SEALS ................................................................... 1-11
CIRCLIPS ................................................................................................. 1-11
BASIC SERVICE INFORMATION .................................................................. 1-12
ELECTRICAL SYSTEM.......... .................................................................. 1-12
SPECIAL TOOLS ........................................................................................... 1-15
CONTROL FUNCTIONS ................................................................................ 1-20
ENGINE STOP SWITCH .......................................................................... 1-20
CLUTCH LEVER ................................................................................... ... 1-20
SHIFT PEDAL .......................................................................................... 1-20
KICKSTARTER LEVER.......... .................................................................. 1-20
THROTTLE GRIP ..................................................................................... 1-20
FRONT BRAKE LEVER ........................................................................... 1-20
REAR BRAKE PEDAL.............................................................................. 1-21
STARTER KNOB/IDLE SCREW .............................................................. 1-21
FUEL TANK CAP ..................................................................................... 1-21

IMPORTANT INFORMATION
1-11
GASKETS, OIL SEALS AND O-RINGS
1. When overhauling the engine, replace all
gaskets and O-rings. All gasket surfaces, oil
seal lips, and O-rings must be cleaned so
that there may be no dust on them.
2. During assembly, always apply proper oil to
bearings and proper grease to oil seal lips
before installation.
EAS1SM1026LOCK WASHERS/PLATES AND COTTER
PINS
After removal, replace lock washers/plates “1”
and cotter pins with new ones. After the bolt or
nut has been tightened to specification, firmly
bend the lock tabs along a flat of the bolt or nut.
EAS1SM1027BEARINGS AND OIL SEALS
Install bearings “1” and oil seals “2” with their
manufacturer’s marks or size symbols facing
outward. During installation of an oil seal, make
sure that its main lip faces the oil chamber (the
target to be sealed). Before installation, always
apply a light coat of grease to the oil seal lip.
ECA13300
NOTICE
Do not spin a bearing with compressed air
because this will damage the bearing sur-
faces.
EAS1SM1028CIRCLIPS
When assembling parts, always use new cir-
clips. During installation of a circlip, make sure
that the edge “2” of the circlip “1” is positioned
opposite to the force “3” that the circlip re-
ceives. Install the circlip with its end aligned
with the center of the spline, without opening
the circlip more than necessary.
1. Oil
2. Lip
3. Spring
4. Grease

BASIC SERVICE INFORMATION
1-12
EAS1SM1029
BASIC SERVICE INFORMATION
EAS1SM1030ELECTRICAL SYSTEM
Electrical parts handling
ECA16620
NOTICE
Handle electrical components with special
care, and do not subject them to strong
shocks.
ECA16630
NOTICE
Electrical components are very sensitive to
and can be damaged by static electricity.
Therefore, never touch the terminals and be
sure to keep the contacts clean.
Checking the electrical system
ECA14371
NOTICE
Never insert the tester probes into the cou-
pler terminal slots. Always insert the probes
from the opposite end “a” of the coupler,
taking care not to loosen or damage the
leads.
ECA16640
NOTICE
For waterproof couplers, never insert the
tester probes directly into the coupler.
When performing any checks using a water-
proof coupler, use the specified test har-
ness or a suitable commercially available
test harness.
Checking the connections
Check leads, couplers, and connectors for
stains, rust, moisture, etc.
1. Disconnect:
• Lead
• Coupler
• Connector
ECA16780
NOTICE
• When disconnecting a coupler, release the
coupler lock, hold both sections of the
coupler, and then disconnect the coupler.
• There are many types of coupler locks;
therefore, be sure to check the type of cou-
pler lock before disconnecting the cou-
pler.
a

CLEANING AND STORAGE
1-27
EAS1SM1049
CLEANING AND STORAGE
EAS1SM1050CLEANING
Frequent cleaning of your vehicle will enhance
its appearance, maintain performance, and ex-
tend the life of parts.
1. Before cleaning, block the silencer outlet to
prevent water from entering. A plastic bag
secured with a rubber band may be used for
this purpose.
2. If the engine is contaminated with oil, apply
some degreaser to it with a brush. Do not
apply degreaser to the drive chain, the
sprockets, or the wheel axles.
3. Hose off dirt. Use only enough water pres-
sure to do the job.
ECA
NOTICE
Do not use high-pressure washers or steam
cleaners. Otherwise, these may cause a fail-
ure because of the entry of water.
4. After hosing off the dirt, wash all surfaces
with a mild detergent and warm water. Use
a toothbrush to clean hard-to-reach places.
5. Rinse the detergent with clean water, and
dry the surfaces with a soft towel or a cloth.
6. Immediately after cleaning, remove any wa-
ter from the drive chain with a paper towel,
and lubricate it to prevent rust.
7. Clean the seat with a vinyl upholstery clean-
er to keep the cover pliable and glossy.
8. Automotive wax may be applied to all paint-
ed or chromed surfaces. Avoid using such
wax as contains abrasives, because it may
scratch surfaces.
9. After completing the above, start the engine
and allow it to warm up for several minutes.
EAS1SM1051STORAGE
If your vehicle is to be stored for 60 days or
more, some preventive measures must be tak-
en to avoid deterioration. After cleaning the ve-
hicle thoroughly, prepare it for storage as
follows:
1. Fill the fuel tank with gasoline.
2. Remove the spark plug, pour a spoonful of
engine oil (SAE 10W-40) into the spark plug
hole, and reinstall the plug. With the engine
stop switch pushed in, by pushing down the
kickstarter lever, crank the engine to coat
the cylinder walls with oil.3. Remove the drive chain, clean it thoroughly
with solvent, and lubricate it Reinstall the
drive chain or store it in a plastic bag tied to
the frame.
4. Lubricate all cables.
5. Lift up the frame of the vehicle to keep the
wheels off the ground.
6. Tie a plastic bag over the muffler outlet to
prevent moisture from entering.
7. If the vehicle is to be stored in a place that is
humid or exposed to the sea breeze, apply a
light coat of oil to metal surfaces. Do not ap-
ply oil to the seat or rubber parts.
TIP
Make any necessary repairs before the vehicle
is stored.

ENGINE SPECIFICATIONS
2-5
Spring tilt (intake) 2.5 °/1.6 mm (2.5 °/0.06 in)
Spring tilt (exhaust) 2.5 °/1.5 mm (2.5 °/0.06 in)
Winding direction (intake) Clockwise
Winding direction (exhaust) Clockwise
Cylinder
Bore 77.000–77.010 mm (3.0315–3.0319 in)
Taper limit 0.050 mm (0.0020 in)
Out of round limit 0.050 mm (0.0020 in)
Piston
Piston-to-cylinder clearance 0.030–0.055 mm (0.0012–0.0022 in)
Limit 0.15 mm (0.006 in)
Diameter D 76.955–76.970 mm (3.0297–3.0303 in)
Height H 6.0 mm (0.24 in)
Offset 0.00 mm (0.0000 in)
Piston pin bore inside diameter 16.002–16.013 mm (0.6300–0.6304 in)
Limit 16.043 mm (0.6316 in)
Piston pin outside diameter 15.991–16.000 mm (0.6296–0.6299 in)
Limit 15.971 mm (0.6288 in)
Piston ring
Top ring
Ring type Barrel
Dimensions (B  T) 0.90  2.70 mm (0.04  0.11 in)
End gap (installed) 0.15–0.25 mm (0.0059–0.0098 in)
Limit 0.50 mm (0.0197 in)
Ring side clearance 0.030–0.065 mm (0.0012–0.0026 in)
Limit 0.120 mm (0.0047 in)
Oil ring
Dimensions (B  T) 1.50  2.25 mm (0.06  0.89 in)
End gap (installed) 0.10–0.35 mm (0.0039–0.0138 in)
H
D
T
B
B
T

CHASSIS SPECIFICATIONS
2-9
Brake disc thickness limit 2.5 mm (0.10 in)
Brake pad lining thickness (inner) 4.4 mm (0.17 in)
Limit 1.0 mm (0.04 in)
Brake pad lining thickness (outer) 4.4 mm (0.17 in)
Limit 1.0 mm (0.04 in)
Master cylinder inside diameter 9.52 mm (0.37 in)
Caliper cylinder inside diameter 22.65 mm  2 (0.89 in  2)
Recommended brake fluid DOT 4
Rear brake
Type Single disc brake
Operation Right foot operation
Rear disc brake
Disc outside diameter  thickness 245.0  4.0 mm (9.65  0.16 in)
Brake disc thickness limit 3.5 mm (0.14 in)
Brake disc deflection limit 0.15 mm (0.0059 in)
Brake pad lining thickness (inner) 6.4 mm (0.25 in)
Limit 1.0 mm (0.04 in)
Brake pad lining thickness (outer) 6.4 mm (0.25 in)
Limit 1.0 mm (0.04 in)
Master cylinder inside diameter 11.0 mm (0.43 in)
Caliper cylinder inside diameter 25.40 mm  1 (1.00 in  1)
Recommended fluid DOT 4
Steering
Steering bearing type Taper roller bearing
Center to lock angle (left) 43.0 °
Center to lock angle (right) 43.0 °
Front suspension
Type Telescopic fork
Spring/shock absorber type Coil spring/oil damper
Front fork travel 310.0 mm (12.20 in)
Fork spring free length 497.0 mm (19.57 in)
Limit 492.0 mm (19.37 in)
Installed length 497.0 mm (19.57 in)
Spring rate K1 4.70 N/mm (0.48 kgf/mm, 26.84 lbf/in) (USA)
(CAN)
4.60 N/mm (0.47 kgf/mm, 26.27 lbf/in) (EUR)
(JPN) (AUS) (NZL) (ZAF)
Spring stroke K1 0.0–310.0 mm (0.00–12.20 in)
Inner tube outer diameter 48.0 mm (1.89 in)
Inner tube bending limit 0.2 mm (0.01 in)
Optional spring available Yes
Recommended oil Suspension oil S1
Standard oil amount 526.0 cm
3 (17.78 US oz, 18.55 Imp.oz) (USA)
(CAN)
551.0 cm
3 (18.63 US oz, 19.43 Imp.oz) (EUR)
(JPN) (AUS) (NZL) (ZAF)
Rebound damping adjusting positions
* Position in which the adjuster is turned in finger tight
Minimum 20 click (s) out*
Standard 9 click (s) out* (USA) (CAN)
8 click (s) out* (EUR) (JPN) (AUS) (NZL) (ZAF)
Maximum (hard) Fully turned in

TIGHTENING TORQUES
2-14
Air filter guide holder screw
M5 8 2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
Air filter case cap screw
M5 1 2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
Starter knob/Idle screw
M12 1 2.1 Nm (0.21 m·kgf, 1.5 ft·lbf)
Throttle cable nut (pull)
M10 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Throttle cable nut (return)
M10 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Clutch cable adjuster and locknut
M6 1 4.3 Nm (0.43 m·kgf, 3.1 ft·lbf)
Clutch cable locknut (engine side)
M8 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Exhaust pipe nut
M8 2 See TIP.
Exhaust pipe protector screw
M6 4 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Exhaust pipe bracket bolt
M8 1 20 Nm (2.0 m·kgf, 14 ft·lbf)
Frame and silencer bolt (front) M8 1 30 Nm (3.0 m·kgf, 22 ft·lbf)
Frame and silencer bolt (rear) M8 1 30 Nm (3.0 m·kgf, 22 ft·lbf)
Exhaust pipe clamp bolt
M8 2 12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Silencer body bolt
M5 6 8 Nm (0.8 m·kgf, 5.8 ft·lbf)
Oil nozzle bolt
M5 1 5 Nm (0.5 m·kgf, 3.6 ft·lbf)
Engine oil drain bolt
M10 1 20 Nm (2.0 m·kgf, 14 ft·lbf)
Crankcase bolt
M6 12 12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Clutch cable holder bolt
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Crankshaft end accessing screw
M36 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Timing mark accessing screw
M14 1 6 Nm (0.6 m·kgf, 4.3 ft·lbf)
Drive chain sprocket cover bolt
M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Crankcase bearing cover plate
screwM6 6 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Crankcase bearing cover plate
screw (crankshaft)M8 4 22 Nm (2.2 m·kgf, 16 ft·lbf)
Oil passage squeeze nozzle
M8 1 3.0 Nm (0.30 m·kgf, 2.2 ft·lbf)
Clutch cover bolt
M6 7 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Left crankcase cover bolt
M6 7 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Right crankcase cover bolt
M6 11 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Oil filter element cover bolt
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Kick shaft ratchet wheel guide
boltM6 2 12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Kick starter lever bolt
M8 1 33 Nm (3.3 m·kgf, 24 ft·lbf)
Kick starter lever boss screw
M6 1 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Primary drive gear nut
M16 1 75 Nm (7.5 m·kgf, 54 ft·lbf)
Clutch spring bolt
M6 5 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Clutch boss nut M16 1 75 Nm (7.5 m·kgf, 54 ft·lbf)Use a lock
washer. ITEMThread
sizeQ’ty TIGHTENING TORQUES Remarks
LT
LT
LT
LT
LT
LT
LT
LT

TIGHTENING TORQUES
2-15
TIP
Exhaust pipe nut
First temporarily tighten nuts to 13 Nm (1.3 m·kgf, 9.4 ft·lbf). Then retighten them to 20 Nm (2.0 m·kgf,
14 ft·lbf).
EAS1SM1058
Drive sprocket nut M18 1 75 Nm (7.5 m·kgf, 54 ft·lbf)Use a lock
washer.
Segment
M8 1 30 Nm (3.0 m·kgf, 22 ft·lbf)
Shift guide bolt
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Stopper lever bolt
M6 1 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
Shift pedal bolt M6 1 12 Nm (1.2 m·kgf, 8.7 ft·lbf)
Rotor nut
M12 1 65 Nm (6.5 m·kgf, 47 ft·lbf)
Stator screw
M5 3 8 Nm (0.8 m·kgf, 5.8 ft·lbf)
Crankshaft position sensor bolt
M6 2 10 Nm (1.0 m·kgf, 7.2 ft·lbf)
AC magneto lead holder bolt
M5 1 8 Nm (0.8 m·kgf, 5.8 ft·lbf)
Coolant temperature sensor
M10 1 16 Nm (1.6 m·kgf, 12 ft·lbf)
Neutral switch bolt
M5 2 3.5 Nm (0.35 m·kgf, 2.5 ft·lbf)
Intake air temperature sensor
screwM5 1 1.5 Nm (0.15 m·kgf, 1.1 ft·lbf)
Rectifier/regulator bolt
M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
ECU bolt
M5 2 3.8 Nm (0.38 m·kgf, 2.8 ft·lbf)
Ignition coil bolt
M6 2 7 Nm (0.7 m·kgf, 5.1 ft·lbf)
Throttle position sensor screw
M5 2 3.4 Nm (0.34 m·kgf, 2.5 ft·lbf)
Intake air pressure sensor screw
M6 1 5 Nm (0.5 m·kgf, 3.6 ft·lbf) ITEMThread
sizeQ’ty TIGHTENING TORQUES Remarks
LT
LT
LT
LT
LT
LT

TIGHTENING TORQUES
2-16
CHASSIS TIGHTENING TORQUES
TIP
- marked portion shall be checked for torque tightening after break-in or before each race.
ITEMThread
sizeQ’ty TIGHTENING TORQUES Remarks
Outer tube and upper bracket bolt M8 4 21 Nm (2.1 m·kgf, 15 ft·lbf)
Outer tube and lower bracket bolt M8 4 21 Nm (2.1 m·kgf, 15 ft·lbf)
Upper bracket and steering stem
nutM24 1 145 Nm (14.5 m·kgf, 105 ft·lbf)
Upper handlebar holder bolt M8 4 28 Nm (2.8 m·kgf, 20 ft·lbf)
Lower handlebar holder nut M10 2 40 Nm (4.0 m·kgf, 29 ft·lbf)
Engine stop switch screw M3 1 0.5 Nm (0.05 m·kgf, 0.36 ft·lbf)
Lower ring nut M28 1 See TIP.
Outer tube and damper assembly M51 2 30 Nm (3.0 m·kgf, 22 ft·lbf)
Inner tube and adjuster M22 2 55 Nm (5.5 m·kgf, 40 ft·lbf)
Damper assembly and base
valveM42 2 28 Nm (2.8 m·kgf, 20 ft·lbf)
Damper assembly adjuster M12 2 29 Nm (2.9 m·kgf, 21 ft·lbf)
Bleed screw (front fork) and base
valveM5 2 1.3 Nm (0.13 m·kgf, 0.94 ft·lbf)
Front fork protector bolt M6 6 5 Nm (0.5 m·kgf, 3.6 ft·lbf)
Front fork protector and brake
hose holder boltM6 2 9 Nm (0.9 m·kgf, 6.5 ft·lbf)
Throttle grip cap screw M5 2 3.8 Nm (0.38 m·kgf, 2.8 ft·lbf)
Clutch lever holder bolt M6 2 5 Nm (0.5 m·kgf, 3.6 ft·lbf)
Clutch lever nut M6 1 4.0 Nm (0.40 m·kgf, 2.9 ft·lbf)
Clutch lever position locknut M5 1
4.8 Nm (0.48 m·kgf, 3.5 ft·lbf)
Front brake master cylinder hold-
er boltM6 2 9 Nm (0.9 m·kgf, 6.5 ft·lbf)
Front brake master cylinder res-
ervoir cap screwM4 2 1.5 Nm (0.15 m·kgf, 1.1 ft·lbf)
Front brake lever pivot bolt M6 1 6 Nm (0.6 m·kgf, 4.3 ft·lbf)
Front brake lever pivot nut M6 1 6 Nm (0.6 m·kgf, 4.3 ft·lbf)
Front brake lever position locknut M6 1 5 Nm (0.5 m·kgf, 3.6 ft·lbf)
Front brake hose holder and low-
er bracket boltM6 1 9 Nm (0.9 m·kgf, 6.5 ft·lbf)
Front brake hose union bolt M10 2 30 Nm (3.0 m·kgf, 22 ft·lbf)
Front brake caliper bolt M8 2 28 Nm (2.8 m·kgf, 20 ft·lbf)
Front brake pad pin M10 1 17 Nm (1.7 m·kgf, 12 ft·lbf)
Front brake pad pin plug M10 1 2.5 Nm (0.25 m·kgf, 1.8 ft·lbf)
Front brake caliper bleed screw M8 1 6 Nm (0.6 m·kgf, 4.3 ft·lbf)
Front wheel axle nut M18 1 115 Nm (11.5 m·kgf, 83 ft·lbf)
LT