2008 YAMAHA YZ250F ABS

CONTENTS
CHAPTER 1
GENERAL INFOR-
MATION
DESCRIPTION ................. 1-1
MACHINE
IDENTIFICATION ............. 1-2
INCLUDED PARTS .......... 1-2
IMPORTANT
INFORMATION................. 1-2
CHECKING OF
CONNECTION .................. 1-3
SPECIAL TOOLS ............. 1-4
CONTROL FUNCTIONS .. 1-8
STARTING AND
BREAK-IN ........................ 1-8
TORQUE-CHECK
POINTS........................... 1-11
CLEANING AND
STORAGE ...................... 1-12
CHAPTER 2
SPECIFICATIONS
GENERAL
SPECIFICATIONS ............ 2-1
MAINTENANCE
SPECIFICATIONS ............ 2-3
TIGHTENING
TORQUES ...................... 2-10
LUBRICATION
DIAGRAMS .................... 2-16
CABLE ROUTING
DIAGRAM ....................... 2-18
CHAPTER 3
REGULAR INSPEC-
TION AND AD-JUSTMENTS
MAINTENANCE
INTERVALS ...................... 3-1
PRE-OPERATION
INSPECTION AND
MAINTENANCE................ 3-5
ENGINE ............................ 3-6
CHASSIS ........................ 3-14
ELECTRICAL ................. 3-23
CHAPTER 4 ENGINE
SEAT, FUEL TANK AND
SIDE COVERS.................. 4-1
EXHAUST PIPE AND
SILENCER ........................ 4-3
RADIATOR ....................... 4-5
CARBURETOR................. 4-7
CAMSHAFTS.................. 4-14
CYLINDER HEAD........... 4-19
VALVES AND VALVE
SPRINGS ........................ 4-21
CYLINDER AND
PISTON ........................... 4-25
CLUTCH ......................... 4-29
OIL FILTER ELEMENT
AND WATER PUMP ....... 4-34
BALANCER .................... 4-38
OIL PUMP ....................... 4-40
KICK SHAFT AND
SHIFT SHAFT ................. 4-44
CDI MAGNETO............... 4-49
ENGINE REMOVAL ....... 4-51
CRANKCASE AND
CRANKSHAFT ............... 4-55
TRANSMISSION, SHIFT
CAM AND SHIFT
FORK .............................. 4-61
CHAPTER 5CHASSIS
FRONT WHEEL AND
REAR WHEEL ..................5-1
FRONT BRAKE AND
REAR BRAKE ..................5-6
FRONT FORK ................. 5-16
HANDLEBAR..................5-24
STEERING ......................5-28
SWINGARM ....................5-32
REAR SHOCK
ABSORBER ....................5-37
CHAPTER 6
ELECTRICAL
ELECTRICAL
COMPONENTS AND
WIRING DIAGRAM ...........6-1
IGNITION SYSTEM...........6-2
THROTTLE POSITION
SENSOR SYSTEM ...........6-5
CHAPTER 7
TUNING
ENGINE.............................7-1
CHASSIS ..........................7-6

1-11
TORQUE-CHECK POINTS
TORQUE-CHECK POINTS
Concerning the tightening torque, refer to "TIGHTENING TORQUES" section in the CHAPTER 2.
Frame constructionFrame to rear frame
Combined seat and fuel tank Fuel tank to frame
Exhaust system Silencer to rear frame
Engine mounting Frame to engine
Engine bracket to engine
Engine bracket to frame
Steering Steering stem to handlebar Steering stem to frame
Steering stem to upper bracket
Upper bracket to handlebar
Suspension Front Steering stem to front fork Front fork to upper bracket
Front fork to lower bracket
Rear For link type Assembly of links
Link to frame
Link to rear shock absorber
Link to swingarm
Installation of rear shock absorber Rear shock absorber to frame
Installation of swingarm Tightening of pivot shaft
Wheel Installation of wheel Front Tightening of wheel axle
Tightening of axle holder
Rear Tightening of wheel axle Wheel to rear wheel sprocket
Brake Front Brake caliper to front fork
Brake disc to wheel
Tightening of union bolt
Brake master cylinder to handlebar
Tightening of bleed screw
Tightening of brake hose holder
Rear Brake pedal to frame Brake disc to wheel
Tightening of union bolt
Brake master cylinder to frame
Tightening of bleed screw
Tightening of brake hose holder
Fuel system Fuel tank to fuel cock
Lubrication system Tightening of oil hose clamp

2-2
GENERAL SPECIFICATIONS
Fuel:Type Premium unleaded gasoline only with a research octane
number of 95 or higher.
Tank capacity 7.0 L (1.54 Imp gal, 1.85 US gal)
Carburetor: Type FCR-MX37
Manufacturer KEIHIN
Spark plug: Type/manufacturer CR8E/NGK (resistance type)
Gap 0.7–0.8 mm (0.028–0.031 in)
Clutch type: Wet, multiple-disc
Transmission: Primary reduction system Gear
Primary reduction ratio 57/17 (3.353)
Secondary reduction system Chain drive
Secondary reduction ratio 49/13 (3.769)
Transmission type Constant mesh, 5-speed
Operation Left foot operation
Gear ratio: 1st 30/14 (2.143)
2nd 28/16 (1.750)
3rd 29/20 (1.450)
4th 27/22 (1.227)
5th 25/24 (1.042)
Chassis: USA, CDN, AUS, NZ, ZAEUROPE
Frame type Semi double cradle
←
Caster angle27.1°26.9°
Trail 116.9 mm (4.60 in) 115.1 mm (4.53 in)
Tire: Type With tube
Size (front) 80/100-21 51M
Size (rear) 100/90-19 57M
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm
2, 15 psi)
Brake: Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation
Suspension: Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber: Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel: Front wheel travel 300 mm (11.8 in)

2-8
MAINTENANCE SPECIFICATIONS
CHASSISHeight
240 mm (9.4 in)----
Thickness 22 mm (0.9 in)----
Radiator cap opening pressure 110 kPa (1.1 kg/cm
2, 15.6 psi)----
Radiator capacity (total) 0.58 L (0.51 Imp qt, 0.61 US qt)----
Water pump Type Single-suction centrifugal pump----
Item
StandardLimit
Item StandardLimit
Steering system: Steering bearing type Taper roller bearing----
Front suspension: 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)----
Optional spring Yes----
Oil capacity 521 cm
3 (18.3 lmp oz, 17.6 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, AUS, NZ,
ZA EUROPE
Shock absorber travel 131.5 mm (5.18 in)
←----
Spring free length Approx.275 mm (10.83 in)
←----
Fitting length One I.D. mark 268 mm (10.55 in) 262 mm (10.31 in) ----
Two I.D. marks 274 mm (10.79 in) 268 mm (10.55 in) ----
Three I.D. marks 265.5 mm (10.45 in) 259.5 mm (10.22 in) ----
One I.D. mark 255.5–273.5 mm (10.06–10.77 in)
←----
Two I.D. marks 261.5–279.5 mm
(10.30–11.00 in)
←----
Three I.D. marks 253.0–271.0 mm (9.96–
10.67 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)←----
Swingarm: Swingarm free play limitEnd ---- 1.0 mm (0.04 in)
Wheel: Front wheel type Spoke wheel----

2-13
TIGHTENING TORQUES
△Rear brake disc coverM6 × 1.0 2 10 1.0 7.2
△Rear brake caliper protector M6 × 1.0 2 7 0.7 5.1
Drive chain puller adjust bolt and locknut M8 × 1.25 2 19 1.9 12
Engine mounting:
△Engine and engine bracket (front) M10 × 1.25 1 53 5.3 38
△Engine and frame (lower) M10 × 1.25 1 53 5.3 38
△Upper engine bracket and frame M8 × 1.25 4 34 3.4 25
△Lower engine bracket and frameM8 × 1.25 4 38 3.8 27
△Engine and engine bracket (upper)M10 × 1.25 1 55 5.5 40
Lower engine guard M6 × 1.0 3 10 1.0 7.2
△Right engine guardM6 × 1.0 1 10 1.0 7.2
CDI unit bracket M6 × 1.0 2 7 0.7 5.1
Cable guide and CDI unit bracket M5 × 0.8 2 4 0.4 2.9
Cable guide and frame M5 × 0.8 1 5 0.5 3.6
△Pivot shaft and nutM16 × 1.5 1 85 8.5 61
△Relay arm and swingarmM14 × 1.5 1 70 7.0 50
△Relay arm and connecting rod M14 × 1.5 1 80 8.0 58
△Connecting rod and frame M14 × 1.5 1 80 8.0 58
△Rear shock absorber and frameM10 × 1.25 1 56 5.6 40
△Rear shock absorber and relay armM10 × 1.25 1 53 5.3 38
△Rear frame (upper) M8 × 1.25 1 38 3.8 27
△Rear frame (lower) M8 × 1.25 2 32 3.2 23
△Swingarm and brake hose holder M5 × 0.8 4 2 0.2 1.4
Swingarm and patch M4 × 0.7 4 2 0.2 1.4
Upper drive chain tensioner M8 × 1.25 1 16 1.6 11
Lower drive chain tensioner M8 × 1.25 1 16 1.6 11
Drive chain support M6 × 1.0 3 7 0.7 5.1
△Seal guard and swingarmM5 × 0.8 4 6 0.6 4.3
△Fuel tank mounting boss and frameM10 × 1.25 1 20 2.0 14
△Fuel tank M6 × 1.0 2 9 0.9 6.5
△Fuel cockM6 × 1.0 2 4 0.4 2.9
Seat set bracket and fuel tank M6 × 1.0 1 7 0.7 5.1
Fuel tank bracket and fuel tank M6 × 1.0 4 7 0.7 5.1
△Air scoop and fuel tankM6 × 1.0 6 7 0.7 5.1
△Air scoop and radiator guard (lower) M6 × 1.0 2 7 0.7 5.1
△Front fenderM6 × 1.0 4 7 0.7 5.1
△Rear fender (front) M6 × 1.0 2 7 0.7 5.1
△Rear fender (rear) M6 × 1.0 2 16 1.6 11
△Side coverM6 × 1.0 2 7 0.7 5.1
Seat M8 × 1.25 2 23 2.3 17
△Number plate M6 × 1.0 1 7 0.7 5.1
Part to be tightened
Thread size Q'tyTightening torque
Nm m•kg ft•lb

2-19
CABLE ROUTING DIAGRAM
F. Pass the clutch cable in front of the radiator mounting boss.
G. Pass the fuel hose between the hot starter cable and throttle po-
sition sensor lead.
H. Pass the carburetor breater hos- es so that they are not pinched
between the upper engine
bracket and carburetor.
I. Pass the carburetor breather
hoses and overflow hose so that
all there hoses do not contact
the rear shock absorber.

2-23
CABLE ROUTING DIAGRAM
1. Brake master cylinder
2. Brake hose holder
3. Brake hose
A. Install the brake hose so that its pipe portion directs as shown
and lightly touches the projec-
tion on the brake caliper.
B. Pass the brake hose into the
brake hose holders. C. If the brake hose contacts the
spring (rear shock absorber),
correct its twist.
D. Install the brake hose so that its pipe portion directs as shown
and lightly touches the projec-
tion on the brake master cylin-
der.

3-3
MAINTENANCE INTERVALS
OIL STRAINERClean
●
FRAMEClean and inspect
●●
FUEL TANK, COCKClean and inspect
●●
BRAKESAdjust lever position and pedal
height
●●
Lubricate pivot point●●
Check brake disc surface●●
Check fluid level and leakage●●
Retighten brake disc bolts, cali-
per bolts, master cylinder bolts
and union bolts●●
Replace pads●
Replace brake fluid●Every one year
FRONT FORKS Inspect and adjust
●●
Replace oil●●Suspension oil "S1"
Replace oil seal
●
FRONT FORK OIL SEAL AND
DUST SEAL Clean and lube
●●Lithium base grease
PROTECTOR GUIDE Replace
●
REAR SHOCK ABSORBERInspect and adjust
●●
Lube●
(After rain
ride)
●Molybdenum disulfide grease
Replace spring seat
●Every one year
Retighten
●●
DRIVE CHAIN GUIDE AND
ROLLERS Inspect
●●
SWINGARMInspect, lube and retighten
●●Molybdenum disulfide grease
RELAY ARM, CONNECTING
ROD Inspect, lube and retighten
●●Molybdenum disulfide grease
STEERING HEAD Inspect free play and retighten
●●
Clean and lube●Lithium base grease
Replace bearing
●
Item After
break-
in Every
race
Every third
(or 500 km) Every
fifth (or 1,000 km)
As re-
quired Remarks