length YAMAHA YZ250F 2010 Owners Manual

FOREWORD
INTRODUCTION
Congratulations on your purchase of
a Yamaha YZ series. This model is
the culmination of Yamaha's vast ex-
perience in the production of paceset-
ting racing machines. It represents
the highest grade of craftsmanship
and reliability that have made Yama-
ha a leader.
This manual explains operation, in-
spection, basic maintenance and tun-
ing of your machine. If you have any
questions about this manual or your
machine, please contact your Yama-
ha dealer.
Yamaha continually seeks advance-
ments in product design and quality.
Therefore, while this manual contains
the most current product information
available at the time of printing, there
may be minor discrepancies between
your machine and this manual. If you
have any questions concerning this
manual, please consult your Yamaha
dealer.
PLEASE READ THIS MANUAL
CAREFULLY AND COMPLETELY
BEFORE OPERATING THIS MA-
CHINE. DO NOT ATTEMPT TO OP-
ERATE THIS MACHINE UNTIL YOU
HAVE ATTAINED A SATISFACTO-
RY KNOWLEDGE OF ITS CON-
TROLS AND OPERATING
FEATURES AND UNTIL YOU HAVE
BEEN TRAINED IN SAFE AND
PROPER RIDING TECHNIQUES.
REGULAR INSPECTIONS AND
CAREFUL MAINTENANCE,
ALONG WITH GOOD RIDING
SKILLS, WILL ENSURE THAT YOU
SAFETY ENJOY THE CAPABILI-
TIES AND THE RELIABILITY OF
THIS MACHINE.
IMPORTANT MANUAL
INFORMATION
Particularly important information is
distinguished in this manual by the
following notations.
This is the safety alert symbol. It is
used to alert you to potential per-
sonal injury hazards. Obey all safe-
ty messages that follow this
symbol to avoid possible injury or
death. A WARNING indicates a hazardous
situation which, if not avoided,
could result in death or serious in-
jury.
A NOTICE indicates special pre-
cautions that must be taken to
avoid damage to the vehicle or oth-
er property.
A TIP provides key information to
make procedures easier or clearer.
SAFETY INFORMATION
THIS MACHINE IS DESIGNED
STRICTLY FOR COMPETITION
USE, ONLY ON A CLOSED
COURSE. It is illegal for this machine
to be operated on any public street,
road, or highway. Off-road use on
public lands may also be illegal.
Please check local regulations before
riding.
• THIS MACHINE IS TO BE OPER-
ATED BY AN EXPERIENCED RID-
ER ONLY.
Do not attempt to operate this ma-
chine at maximum power until you
are totally familiar with its character-
istics.
• THIS MACHINE IS DESIGNED TO
BE RIDDEN BY THE OPERATOR
ONLY.
Do not carry passengers on this
machine.
• ALWAYS WEAR PROTECTIVE APPAREL.
When operating this machine, al-
ways wear an approved helmet with
goggles or a face shield. Also wear
heavy boots, gloves, and protective
clothing. Always wear proper fitting
clothing that will not be caught in
any of the moving parts or controls
of the machine.
• ALWAYS MAINTAIN YOUR MA- CHINE IN PROPER WORKING
ORDER.
For safety and reliability, the ma-
chine must be properly maintained.
Always perform the pre-operation
checks indicated in this manual.
Correcting a mechanical problem
before you ride may prevent an ac-
cident.
• GASOLINE IS HIGHLY FLAMMA-
BLE.
Always turn off the engine while re-
fueling. Take care to not spill any
gasoline on the engine or exhaust
system. Never refuel in the vicinity of an open flame, or while smoking.
• GASOLINE CAN CAUSE INJURY. If you should swallow some gaso-
line, inhale excess gasoline vapors,
or allow any gasoline to get into
your eyes, contact a doctor immedi-
ately. If any gasoline spills onto
your skin or clothing, immediately
wash skin areas with soap and wa-
ter, and change your clothes.
• ONLY OPERATE THE MACHINE IN AN AREA WITH ADEQUATE
VENTILATION.
Never start the engine or let it run
for any length of time in an enclosed
area. Exhaust fumes are poison-
ous. These fumes contain carbon
monoxide, which by itself is odor-
less and colorless. Carbon monox-
ide is a dangerous gas which can
cause unconsciousness or can be
lethal.
• PARK THE MACHINE CAREFUL- LY; TURN OFF THE ENGINE.
Always turn off the engine if you are
going to leave the machine. Do not
park the machine on a slope or soft
ground as it may fall over.
• THE ENGINE, EXHAUST PIPE, MUFFLER, AND OIL TANK WILL
BE VERY HOT AFTER THE EN-
GINE HAS BEEN RUN.
Be careful not to touch them or to
allow any clothing item to contact
them during inspection or repair.
• PROPERLY SECURE THE MA- CHINE BEFORE TRANSPORTING
IT.
When transporting the machine in
another vehicle, always be sure it is
properly secured and in an upright
position and that the fuel cock is in
the "OFF" position. Otherwise, fuel
may leak out of the carburetor or
fuel tank.
F.I.M. MACHINE WEIGHTS
Weights of machines without fuel
The minimum weights for motocross
machines are:
for the class 125 cc:
minimum 88 kg (194 lb)
for the class 250 cc:
minimum 98 kg (216 lb)
for the class 500 cc:
minimum 102 kg (225 lb)
In modifying your machine (e.g., for
weight reduction), take note of the
above limits of weight.

2-1
GENERAL SPECIFICATIONS
SPECIFICATIONS
GENERAL SPECIFICATIONS
Model name:YZ250FZ (USA, CDN, AUS, NZ)
YZ250F (EUROPE, ZA)
Model code number: 17D5 (USA,CDN)
17D6 (EUROPE)
17D8 (AUS, NZ, ZA)
Dimensions: USA, CDN EUROPE AUS, NZ, ZA
Overall length 2,159 mm (85.00
in) 2,168 mm (85.35
in)2,166 mm (85.28
in)
Overall width 825 mm (32.48 in)←←
Overall height 1,303 mm (51.30
in) 1,304 mm (51.34
in)←
Seat height 988 mm (38.90 in) 991 mm (39.02 in) 990 mm (38.98 in)
Wheelbase 1,466 mm (57.72
in) 1,473 mm (57.99
in)←
Minimum ground clearance 375 mm (14.76 in) 377 mm (14.84 in) 376 mm (14.80 in)
Weight: With oil and fuel 102.0 kg (224.9 lb)
Engine: Engine type Liquid cooled 4-stroke, DOHC
Cylinder arrangement Single cylinder, forward inclined
Displacement 250 cm
3 (8.80 Imp oz, 8.45 US oz)
Bore × stroke 77.0 × 53.6 mm (3.03 × 2.11 in)
Compression ratio 13.5 : 1
Starting system Kickstarter
Lubrication system: Dry sump
Oil type or grade: Engine oil Recommended brand: YAMALUBE
SAE10W-30, SAE10W-40, SAE10W-50
SAE15W-40, SAE20W-40 or SAE20W-50
API service SG type or higher,
JASO standard MA
Oil capacity: Engine oilPeriodic oil change 0.95 L (0.84 Imp qt, 1.00 US qt)
With oil filter replacement 1.05 L (0.92 Imp qt, 1.11 US qt)
Total amount 1.20 L (1.06 Imp qt, 1.27 US qt)
Coolant capacity (including all routes): 1.00 L (0.88 Imp qt, 1.06 US qt)
Air filter: Wet type element
Fuel: Type Premium unleaded gasoline only with a research octane
number of 95 or higher.
Tank capacity 6.4 L (1.4 Imp gal, 1.69 US gal)
2

2-5
MAINTENANCE SPECIFICATIONS
Stem runout limit----0.01 mm
(0.0004 in)
Valve seat width (IN) 0.9–1.1 mm (0.0354–0.0433 in) 1.6 mm (0.0630
in)
Valve seat width (EX) 0.9–1.1 mm (0.0354–0.0433 in) 1.6 mm (0.0630
in)
Valve spring: Free length (IN) 39.76 mm (1.57 in)38.76 mm (1.53
in)
Free length (EX) 37.78 mm (1.49 in)36.78 mm (1.45
in)
Set length (valve closed ) (IN) 28.98 mm (1.14 in) ----
Set length (valve closed ) (EX) 28.30 mm (1.11 in) ----
Compressed force (installed) (IN) 99–114 N at 28.98 mm (9.9–11.4 kg at
28.98 mm, 22.27–25.57 lb at 1.14 in) ----
Compressed force (installed) (EX) 126–145 N at 28.30 mm (12.6–14.5 kg at
28.30 mm, 28.44–31.97 lb at 1.11 in) ----
Tilt limit* (IN) ----2.5°/1.7 mm
(2.5°/0.067 in)
Tilt limit* (EX) ----2.5°/1.6 mm
(2.5°/0.063 in)
Direction of winding (top view) (IN) Clockwise----
Direction of winding (top view) (EX) Clockwise----
Piston: Piston to cylinder clearance 0.030–0.055 mm (0.0012–0.0022 in) 0.1 mm (0.004
in)
Piston size "D" 76.955–76.970 mm (3.0297–3.0303 in) ----
Measuring point "H " 8 mm (0.31 in) ----
Piston off-set 0.5 mm (0.020 in)/IN-side----
Item
StandardLimit

2-7
MAINTENANCE SPECIFICATIONS
Clutch:Friction plate thickness 2.9–3.1 mm (0.114–0.122 in)2.8 mm (0.110
in)
Quantity 9----
Clutch plate thickness 1.1–1.3 mm (0.043–0.051 in)----
Quantity 8----
Warp limit ----0.1 mm (0.004
in)
Clutch spring free length 35.7 mm (1.41 in)34.7 mm (1.37
in)
Quantity 5----
Clutch housing thrust clearance 0.050–0.300 mm (0.0020–0.0118 in) ----
Clutch housing radial clearance 0.010–0.044 mm (0.0004–0.0017 in) ----
Clutch release method Inner push, cam push----
Shifter: Shifter type Cam drum and guide bar----
Guide bar bending limi t ---- 0.05 mm (0.002
in)
Kickstarter: Type Kick and ratchet type----
Carburetor: USA, CDNEUROPE, AUS, NZ,
ZA
Type/manufacturer FCR-MX37/KEIHIN← ----
I. D. mark 17D5 5017D6 60----
Main jet (M.J) #180←----
Main air jet (M.A.J) ø2.0← ----
Jet needle-clip position (J.N) NDJR-4NHKR-4 ----
Cutaway (C.A) 1.5←----
Pilot jet (P.J) #45#42 ----
Pilot air jet (P.A.J) #105← ----
Pilot outlet (P.O) ø0.9←----
Pilot screw (example) (P.S) 1-3/4←----
Bypass (B.P) ø1.0←----
Valve seat size (V.S) ø3.8←----
Starter jet (G.S) #72← ----
Leak jet (Acc.P) #70#110 ----
Float height (F.H) 8 mm (0.31 in)← ----
Engine idle speed 1,900–2,100 r/min← ----
Intake vacuum 29.3–34.7 kPa
(220–260 mmHg,
8.66–9.45 inHg) ←
----
Hot starter lever free play 3–6 mm (0.12–0.24
in) ←
----
Item
StandardLimit

2-8
MAINTENANCE SPECIFICATIONS
CHASSISLubrication system:
Oil filter type Paper type----
Oil pump type Trochoid type----
Tip clearance 0.12 mm or less (0.0047 in or less) 0.20 mm (0.008
in)
Side clearance 0.09–0.17 mm (0.0035–0.0067 in) 0.24 mm (0.009
in)
Housing and rotor clearance 0.03–0.10 mm (0.0012–0.0039 in) 0.17 mm
(0.0067 in)
Cooling: Radiator core sizeWidth 121.4 mm (4.8 in)----
Height 235 mm (9.3 in)----
Thickness 28 mm (1.1 in)----
Radiator cap opening pressure 110 kPa (1.1 kg/cm
2, 15.6 psi)----
Radiator capacity (total) 0.64 L (0.56 Imp qt, 0.68 US qt)----
Water pump Type Single-suction centrifugal pump----
Item
StandardLimit
Item StandardLimit
Steering system: Steering bearing type Taper roller bearing----
Front suspension: USA, CDN EUROPE, AUS, NZ, ZA
Front fork travel 300 mm (11.8 in)←----
Fork spring free length 454 mm (17.9 in)←449 mm (17.7
in)
Spring rate, STD K = 4.4 N/mm (0.449 kg/
mm, 25.1 lb/in) K = 4.5 N/mm (0.459 kg/
mm, 25.7 lb/in)----
Optional spring Yes← ----
Oil capacity 541 cm
3 (19.0 lmp oz,
18.3 US oz) 528 cm3 (18.6 lmp oz,
17.9 US oz) ----
Oil grade Suspension oil "S1"←----
Inner tube outer diameter 48 mm (1.89 in)←----
Front fork top end 5 mm (0.20 in)←----
Rear suspension: USA, CDN EUROPE, AUS, NZ, ZA
Shock absorber travel 131.5 mm (5.18 in)←----
Spring free length 260 mm (10.24 in)←----
Fitting length 250 mm (9.84 in)←
Preload length
1.5–20 mm (0.06–0.79
in) ←
----
Spring rate, STD K = 52.0 N/mm (5.30 kg/
mm, 296.8 lb/in) ←
----
Optional spring Yes← ----
Enclosed gas pressure 1,000 kPa (10 kg/cm
2,
142 psi) ←
----

2-9
MAINTENANCE SPECIFICATIONS
Swingarm:Swingarm free play limitEnd ---- 1.0 mm (0.04
in)
Wheel: Front wheel type Spoke wheel----
Rear wheel type Spoke wheel----
Front rim size/materia l 21 × 1.60/Aluminum ----
Rear rim size/materia l 19 × 1.85/Aluminum ----
Rim runout limit: Radial ---- 2.0 mm (0.08
in)
Lateral ---- 2.0 mm (0.08
in)
Drive chain: USA, CDN EUROPE, AUS, NZ, ZA
Type/manufacturer DID520DMA2 SDH/
DAIDO ←
----
Number of links 111 links + joint 113 links + joint ----
Chain slack 50–60 mm (2.0–2.4 in)←----
Chain length (15 links) ----←242.9 mm
(9.563 in)
Front disc brake: Disc outside dia.×Thickness 250 × 3.0 mm (9.84 × 0.12 in)250 × 2.5 mm
(9.84 × 0.10 in)
Pad thickness 4.4 mm (0.17 in)1.0 mm (0.04
in)
Master cylinder inside dia. 9.52 mm (0.375 in)----
Caliper cylinder inside dia. 22.65 mm (0.892 in) × 2 ----
Brake fluid type DOT #4----
Rear disc brake: Disc outside dia.×Thickness 245 × 4.0 mm (9.65 × 0.16 in)245 × 3.5 mm
(9.65 × 0.14 in)
Deflection limit ----0.15 mm
(0.006 in)
Pad thickness 6.4 mm (0.25 in)1.0 mm (0.04
in)
Master cylinder inside dia. 11.0 mm (0.433 in)----
Caliper cylinder inside dia. 25.4 mm (1.000 in) × 1----
Brake fluid type DOT #4----
Brake lever and brake pedal: Brake lever position 95 mm (3.74 in)----
Brake pedal height (vertical height above footrest
top) Zero mm (Zero in)
----
Clutch lever free play (lever end) 7–12 mm (0.28–0.47 in)----
Throttle grip free play 3–5 mm (0.12–0.20 in)----
Item
StandardLimit

2-15
TIGHTENING TORQUES
GENERAL TORQUE
SPECIFICATIONS
This chart specifies torque for stan-
dard fasteners with standard I.S.O.
pitch threads. Torque specifications
for special components or assem-
blies are included in the applicable
sections of this book. To avoid war-
page, tighten multi-fastener assem-
blies in a crisscross fashion, in
progressive stages, until full torque is
reached. Unless otherwise specified,
torque specifications call for clean,
dry threads. Components should be
at room temperature.A. Distance between flats
B. Outside thread diameter
DEFINITION OF UNITS
A
(Nut) B
(Bolt
) TORQUE SPECIFI-
CATION
Nm m•kg ft•lb
10
mm 6 mm 6 0.6 4.3
12
mm 8 mm 15 1.5 11
14
mm 10
mm 30 3.0 22
17
mm 12
mm 55 5.5 40
19
mm 14
mm 85 8.5 61
22
mm 16
mm 130 13 94
Unit
Read Definition Measure
mm
millimeter 10-3 meterLength
cmcentimeter 10-2 meterLength
kgkilogram 103 gramWeight
NNewton 1 kg × m/sec2Force
NmNewton meter N × mTorque
m•kgMeter kilogram m × kg Torque
PaPascalN/m2Pressure
N/mmNewton per millimeter N/mm Spring rate
LLiter—Volume or capacity
cm3Cubic centimeter —Volume or capacity
r/minRevolution per minute —Engine speed

3-1
MAINTENANCE INTERVALS
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
• The following schedule is intended as a general guide to mainten ance and lubrication. Bear in mind that such factors as
weather, terrain, geographical location, and individual usage will alter the required maintenance and lubrication intervals.
If you are a doubt as to what intervals to follow in mainta ining and lubricating your machine, consult your Yamaha dealer
• Periodic inspection is essential in making full use of the ma chine performance. The service life of the parts varies sub-
stantially according to the environment in which the machine runs (e.g., rain, dirt, etc.). Therefore, earlier inspection is
required by reference to the list below.
Item After
break- in Every
race
(about 2.5
hours)
Every third
(about
7.5
hours) Every
fifth
(about
12.5
hours)
As re-
quired Remarks
ENGINE OIL Replace ●●
Inspect ●●
OIL FILTER ELEMENT, OIL
STRAINER Clean ●
VALVES Check the valve clearances ●● The engine must be cold.
Inspect ●Check the valve seats and valve
stems for wear.
Replace ●
VALVE SPRINGS Inspect ●Check the free length and the tilt.
Replace ●
VALVE LIFTERS Inspect ●Check for scratches and wear.
Replace ●
CAMSHAFTS Inspect the camshaft surface.
Inspect ●Inspect the decompression system.
Replace ●
TIMING CHAIN SPROCKETS,
TIMING CHAIN Inspect ●Check for wear on the teeth and for
damage.
Replace ●
PISTON Inspect ●●Inspect crack.
Clean ●Inspect carbon deposits and eliminate
them.
Replace ●It is recommended that the piston pin
and ring are also replaced at the same
time.
PISTON RING Inspect ●Check ring end gap.
Replace ●●
3

3-17
CHASSIS
CHECKING THE SPROCKET
1. Inspect:• Sprocket teeth "a"Excessive wear →Replace.
Replace the drive sprocket, rear
wheel sprocket and drive chain as a
set.
CHECKING THE DRIVE CHAIN
1. Measure:
• Drive chain length (15 links) "a"Out of specification →Replace.
• While measuring the drive chain
length, push down on the drive
chain to increase its tension.
• Measure the length between drive
chain roller "1" and "16" as shown.
• Perform this measurement at two or three different places.
2. Remove:• Master link clip
•Joint "1"
• Drive chain "2" 3. Clean:
• Drive chainPlace it in kerosene, and brush off
as much dirt as possible. Then re-
move the drive chain from the ker-
osene and dry the drive chain.
4. Check: • Drive chain stiffness "a"
Clean and oil the drive chain and
hold as illustrated.
Stiff →Replace the drive chain.
5. Install: • Drive chain "1"
•Joint "2"
• Master link clip "3"
Be sure to install the master link
clip to the direction as shown.
a. Turning direction
6. Lubricate: • Drive chain ADJUSTING THE DRIVE CHAIN
SLACK
1. Elevate the rear wheel by placing
the suitable stand under the en-
gine.
2. Check: • Drive chain slack "a"
Above the seal guard installation
bolt.
Out of specification →Adjust.
Before checking and/or adjusting, ro-
tate the rear wheel through several
revolutions and check the slack sev-
eral times to find the tightest point.
Check and/or adjust the drive chain
slack with the rear wheel in this "tight
chain" position.
3. Adjust:
• Drive chain slack
Drive chain slack adjustment
steps:
a. Loosen the axle nut "1" and lock- nuts "2".
b. Adjust the drive chain slack by turning the adjusters "3".
c. Turn each adjuster exactly the same amount to maintain correct
axle alignment. (There are marks
"a" on each side of the drive chain
puller alignment.) NOTICE: Im-
proper drive chain slack will
overload the engine aswell as
other vital parts of the motorcy-
cle and can lead to chain slip-
page or breakage. To prevent
this from occurring, keep the
drive chain slack within the
specified limits.
Drive chain length (15
links):
: 242.9 mm
(9.563 in)
Drive chain lubricant:
SAE 10W-40 motor oil
or suitable chain lubri-
cants
Drive chain slack: 50–60 mm (2.0–2.4 in)
To tighten →Turn the adjuster "3"
counterclockwise.
To loosen →Turn the adjuster "3"
clockwise and push wheel for-
ward.

3-19
CHASSIS
ADJUSTING THE FRONT FORK
COMPRESSION DAMPING FORCE
2. Adjust:• Compression damping force
By turning the adjuster "1".
• STANDARD POSITION: This is the position which is back
by the specific number of clicks
from the fully turned-in position.
Do not force the adjuster past the
minimum or maximum extent of
adjustment. The adjuster may be
damaged.
Always adjust each front fork to
the same setting. Uneven adjust-
ment can cause poor handling and
loss of stability.
CHECKING THE REAR SHOCK
ABSORBER
1. Inspect:• Swingarm smooth actionAbnormal noise/unsmooth action
→ Grease the pivoting points or
repair the pivoting points.
Damage/oil leakage →Replace. ADJUSTING THE REAR SHOCK
ABSORBER SPRING PRELOAD
1. Elevate the rear wheel by placing
the suitable stand under the en-
gine.
2. Remove: • Rear frame
3. Measure:
• Spring fitting length
The I.D. mark "a" is marked at the end
of the spring.
4. Adjust: • Spring preload
Adjustment steps:
a. Loosen the locknut "1".
b. Loosen the adjuster "2" until there is some clearance between the
spring and adjuster.
c. Measure the spring free length
"a".
d. Turn the adjuster "2".
• Be sure to remove all dirt and mud from around the locknut and adjust-
er before adjustment.
• The length of the spring (installed) changes 1.5 mm (0.06 in) per turn
of the adjuster.
Never attempt to tu rn the adjuster
beyond the maximum or minimum
setting.
e. Tighten the locknut.
5. Install: • Rear frame (upper)
• Rear frame (lower)
ADJUSTING THE REAR SHOCK
ABSORBER REBOUND DAMPING
FORCE
1. Adjust: • Rebound damping forceBy turning the adjuster "1".
Stiffer "a"
→Increase the com-
pression damping force. (Turn
the adjuster "1" in.)
Softer "b" →Decrease the com-
pression damping force. (Turn
the adjuster "1" out.)
Extent of adjustment:
Maximum Minimum
Fully turned in
position 20 clicks out
(from maximum
position)
Standard position: 8 clicks out
* 6 clicks out
* Except for USA and CDN
Standard fitti ng length:
I.D. MARK/Q'TY Length
Yellow/1 250 mm (9.84 in)
Stiffer →Increase the spring pre-
load. (Turn the adjuster "2" in.)
Softer →Decrease the spring pre-
load. (Turn the adjuster "2"
out.)
Extent of adjustment:
Maximum Minimum
Position in
which the
spring is turned
in 20 mm (0.79
in) from its free
length. Position in
which the
spring is turned
in 1.5 mm (0.06
in) from its free
length.
Locknut: 30 Nm (3.0 m•kg, 22
ft•lb)
Rear frame (upper): 32 Nm (3.2 m•kg, 23
ft•lb)
Rear frame (lower): 32 Nm (3.2 m•kg, 23
ft•lb)
Stiffer "a" →Increase the re-
bound damping force. (Turn
the adjuster "1" in.)
Softer "b" →Decrease the re-
bound damping force. (Turn
the adjuster "1" out.)