wheel size YAMAHA YZ250F 2011 Owners Manual

2-2
GENERAL SPECIFICATIONS
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: USA, CDN EUROPE, AUS, NZ, ZA Primary reduction system Gear ←
Primary reduction ratio 57/17 (3.353) ←
Secondary reduction system Chain drive ←
Secondary reduction ratio 49/13 (3.769) 51/13 (3.923)
Transmission type Constant mesh, 5-speed ←
Operation Left foot operation ←
Gear ratio:
1st 30/14 (2.143) ←
2nd 28/16 (1.750) ←
3rd 26/18 (1.444) ←
4th 22/18 (1.222) ←
5th 25/24 (1.042) ←
Chassis: USA, CDN EUROPE AUS, NZ, ZA
Frame type Semi double cra- dle←←
Caster angle 27.5° 27.2° 27.4°
Trail 120.2 mm (4.73 in)117.4 mm (4.62
in)119.6 mm (4.71
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: USA, CDN EUROPE, AUS, NZ, ZA Front wheel travel 300 mm (11.8 in) ←
Rear wheel travel 307 mm ( 12.1 in) 310 mm (12.2 in)
Electrical: Ignition system CDI magneto

2-9
MAINTENANCE SPECIFICATIONS
Swingarm:
Swingarm free play limit
End ---- 1.0 mm (0.04
in)
Wheel:
Front wheel type Spoke wheel ----
Rear wheel typeSpoke wheel ----
Front rim size/material 21 × 1.60/Aluminum ----
Rear rim size/material 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 play3–5 mm (0.12–0.20 in) ---- Item Standard Limit

2-11
TIGHTENING TORQUES
Oil filter element drain bolt M6 × 1.0 1 10 1.0 7.2
Oil filter element cover M6 × 1.0 2 10 1.0 7.2
Oil strainer (crankcase) M6 × 1.0 2 10 1.0 7.2
Oil delivery pipe 1 (M10) M10 × 1.25 1 20 2.0 14
Oil delivery pipe 1 (M8) M8 × 1.25 2 18 1.8 13
△ Oil hose M6 × 1.0 2 8 0.8 5.8
Oil hose clamp — 1 2 0.2 1.4
Oil strainer (oil tank) M6 × 1.0 1 9 0.9 6.5
Oil tank drain bolt M8 × 1.25 1 18 1.8 13
Oil tank (upper) M6 × 1.0 1 4 0.4 2.9
Oil tank and frame M6 × 1.0 3 9 0.9 6.5
Carburetor joint clamp M5 × 0.8 1 3 0.3 2.2
Air filter joint clamp M6 × 1.0 1 3 0.3 2.2
Throttle cable adjust bolt and locknut M6 × 0.75 1 4 0.4 2.9
Throttle cable (pull) M6 × 1.0 1 4 0.4 2.9
Throttle cable (return) M12 × 1.0 1 11 1.1 8.0
Throttle cable cover M5 × 0.8 2 4 0.4 2.9
Hot starter plunger M12 × 1.0 1 2 0.2 1.4
Hot starter cable adjust bolt and locknut M6 × 0.75 1 4 0.4 2.9
△ Air filter case M6 × 1.0 2 8 0.8 5.8
Air filter joint and air filter case M5 × 0.8 1 4 0.4 2.9
Air filter element M6 × 1.0 1 2 0.2 1.4
Exhaust pipe M8 × 1.25 2 20 2.0 14
△ Exhaust pipe protector M6 × 1.0 3 10 1.0 7.2
△ Silencer M8 × 1.25 2 30 3.0 22
Silencer clamp M8 × 1.25 1 14 1.4 10
Crankcase M6 × 1.0 11 12 1.2 8.7
Crankcase bearing stopper M6 × 1.0 11 10 1.0 7.2
Crankcase bearing stopper (crankshaft) M6 × 1.0 4 14 1.4 10
Left crankcase cove r M6 × 1.0 8 10 1.0 7.2
Right crankcase cove r M6 × 1.0 8 10 1.0 7.2
Clutch cover M6 × 1.0 7 10 1.0 7.2
Crankcase oil drain bolt M10 × 1.25 1 20 2.0 14
△ Crankshaft end accessing screw M32 × 1.5 1 — — —
△ Timing mark accessing screw M14 × 1.5 1 — — —
△ Drive chain sprocket cover M6 × 1.0 2 7 0.7 5.1
Kick shaft ratchet wheel guide M6 × 1.0 2 12 1.2 8.7
Kickstarter crank M8 × 1.25 1 33 3.3 24
Primary drive gear M18 × 1.0 1 75 7.5 54
Clutch spring M6 × 1.0 5 10 1.0 7.2
Clutch boss M16 × 1.0 1 75 7.5 54
Clutch cable locknut M8 × 1.25 1 7 0.7 5.1
Clutch cable adjust bolt and locknut M6 × 0.75 1 4 0.4 2.9
Push lever shaft M6 × 1.0 1 10 1.0 7.2 Part to be tightened Thread size Q'ty
Tightening torque
Nm m•kg ft•lb

2-12
TIGHTENING TORQUES
CHASSIS
△- marked portion shall be checked for torque tightening after break-in or before each race.
Drive sprocket M18 × 1.0 1 75 7.5 54
Drive axle oil seal stopper M6 × 1.0 2 10 1.0 7.2
Segment M8 × 1.25 1 30 3.0 22
Shift guide M6 × 1.0 2 10 1.0 7.2
Stopper lever M6 × 1.0 1 10 1.0 7.2
Shift pedal M6 × 1.0 1 12 1.2 8.7Part to be tightened Thread size Q'tyTightening torque
Nm m•kg ft•lb
Part to be tightened Thread size Q'tyTightening torque
Nm m•kg ft•lb
△Upper bracket and outer tube M8 × 1.25 4 21 2.1 15
△Lower bracket and outer tube M8 × 1.25 4 21 2.1 15
△Upper bracket and steering stem M24 × 1.0 1 145 14.5 105
△Handlebar upper holder and handlebar lower holder M8 × 1.25 4 28 2.8 20
△Handlebar lower holder and upper bracket M10 × 1.25 2 34 3.4 25
△Steering stem and steering ring nut M28 × 1.0 1 Refer to TIP.
Front fork and damper assembly M51 × 1.5 2 30 3.0 22
Front fork and adjuster M22 × 1.25 2 55 5.5 40
Damper assembly and base valve M42 × 1.5 2 29 2.9 21
Adjuster and damper assembly M12 × 1.25 2 29 2.9 21
Front fork bleed screw and base valve M5 × 0.8 2 1 0.1 0.7
△Front fork and front fork protector M6 × 1.0 6 5 0.5 3.6
△Lower bracket and brake hose guide M6 × 1.0 1 9 0.9 6.5
△Front fork protector and brake hose holder M6 × 1.0 2 8 0.8 5.8
Throttle grip cap M5 × 0.8 2 4 0.4 2.9
△Front brake master cylinder M6 × 1.0 2 9 0.9 6.5
Brake lever mounting bolt M6 × 1.0 1 6 0.6 4.3
Brake lever mounting nut M6 × 1.0 1 6 0.6 4.3
Brake lever position locknut M6 × 1.0 1 5 0.5 3.6
Clutch lever holder M6 × 1.0 2 5 0.5 3.6
Clutch lever mounting nut M6 × 1.0 1 4 0.4 2.9
Clutch lever position lock nut M5 × 0.8 1 5 0.5 3.6
Hot starter lever holder M5 × 0.8 2 4 0.4 2.9
Front brake master cylinder cap M4 × 0.7 2 2 0.2 1.4
△Front brake hose union bolt M10 × 1.25 2 30 3.0 22
△Front brake caliper M8 × 1.25 2 28 2.8 20
Pad pin plug M10 × 1.0 2 3 0.3 2.2
△Front brake caliper and pad pin M10 × 1.0 1 18 1.8 13
△Rear brake caliper and pad pin M10 × 1.0 1 18 1.8 13
△Brake caliper and bleed screw M8 × 1.25 2 6 0.6 4.3
△Front wheel axle and axle nut M16 × 1.5 1 105 10.5 75
△Front wheel axle holder M8 × 1.25 4 21 2.1 15

2-13
TIGHTENING TORQUES
△Front brake disc M6 × 1.0 6 12 1.2 8.7
△Rear brake disc M6 × 1.0 6 14 1.4 10
△Footrest bracket and frame M10 × 1.25 4 55 5.5 40
△Brake pedal M8 × 1.25 1 26 2.6 19
△Rear brake master cylinder M6 × 1.0 2 10 1.0 7.2
Rear brake master cylinder cap M4 × 0.7 2 2 0.2 1.4
△Rear brake hose union bolt M10 × 1.25 2 30 3.0 22
△Rear wheel axle and axle nut M22 × 1.5 1 135 13.5 98
△Nipple (spoke) — 72 3 0.3 2.2
△Rear wheel sprocket M8 × 1.25 6 42 4.2 30
△Rear brake disc cover M6 × 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 21 2.1 15
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
△Front engine bracket and frame M8 × 1.25 4 34 3.4 25
△Engine and engine bracket (upper) M10 × 1.25 2 55 5.5 40
Lower engine guard M6 × 1.0 3 10 1.0 7.2
CDI unit bracket M6 × 1.0 2 7 0.7 5.1
Cable guide and frame M6 × 1.0 2 7 0.7 5.1
△Pivot shaft and nut M16 × 1.5 1 85 8.5 61
△Relay arm and swingarm M14 × 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 frame M10 × 1.25 1 56 5.6 40
△Rear shock absorber and relay arm M10 × 1.25 1 53 5.3 38
△Rear frame (upper) M8 × 1.25 2 32 3.2 23
△Rear frame (lower) M8 × 1.25 2 32 3.2 23
△Swingarm and brake hose holder M5 × 0.8 4 3 0.3 2.2
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 swingarm M5 × 0.8 4 6 0.6 4.3
△Fuel tank M6 × 1.0 1 9 0.9 6.5
△Fuel cock M6 × 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 2 7 0.7 5.1
Side cover set bracket and fuel tank M6 × 1.0 2 7 0.7 5.1
Fitting band set screw and fuel tank M6 × 1.0 1 7 0.7 5.1
△Air scoop and fuel tank M6 × 1.0 2 7 0.7 5.1
△Air scoop and radiator guard M6 × 1.0 4 7 0.7 5.1
Air scoop and frame M6 × 1.0 2 7 0.7 5.1Part to be tightened Thread size Q'tyTightening torque
Nm m•kg ft•lb

7-6
CHASSIS
CHASSIS
SELECTION OF THE SECONDARY
REDUCTION RATIO (SPROCKET)
<Requirement for selection of sec-
ondary gear reduction ratio>
• It is generally said that the second-
ary gear ratio should be reduced for
a longer straight portion of a speed
course and should be increased for
a course with many corners. Actual-
ly, however, as the speed depends
on the ground condition of the day
of the race, be sure to run through
the circuit to set the machine suit-
able for the entire course.
• In actuality, it is very difficult to
achieve settings suitable for the en-
tire course and some settings may
be sacrificed. Thus, the settings
should be matched to the portion of
the course that has the greatest ef-
fect on the race result. In such a
case, run through the entire course
while making notes of lap times to
find the best balance; then, deter-
mine the secondary reduction ratio.
• If a course has a long straight por-
tion where a machine can run at
maximum speed, the machine is
generally set such that it can devel-
op its maximum revolutions toward
the end of the straight line, with care
taken to avoid the engine over-rev-
ving.
Riding technique varies from rider to
rider and the performance of a ma-
chine also vary from machine to ma-
chine. Therefore, do not imitate other
rider's settings from the beginning but
choose your own setting according to
the level of your riding technique.
DRIVE AND REAR WHEEL
SPROCKETS SETTING PARTS
TIRE PRESSURE
Tire pressure should be adjust to suit
the road surface condition of the cir-
cuit.
• Under a rainy, muddy, sandy, or
slippery condition, the tire pressure
should be lower for a larger area of
contact with the road surface.
• Under a stony or hard road condi-
tion, the tire pressure should be
higher to prevent a flat tire.FRONT FORK SETTING
The front fork setting should be made
depending on the rider's feeling of an
actual run and the circuit conditions.
The front fork setting includes the fol-
lowing three factors:
1. Setting of air spring characteris-
tics
• Change the fork oil amount.
2. Setting of spring preload
• Change the spring.
3. Setting of damping force
• Change the compression damp-
ing.
• Change the rebound damping.
The spring acts on the load and
the damping force acts on the
cushion travel speed.
CHANGE IN AMOUNT AND
CHARACTERISTICS OF FORK OIL
Damping characteristic near the final
stroke can be changed by changing
the fork oil amount.
Adjust the oil amount in 5 cm3 (0.2
Imp oz, 0.2 US oz) increments or
decrements. Too small oil amount
causes the front fork to produce a
noise at full rebound or the rider to
feel some pressure on his hands
or body. Alternatively, too large oil
amount will cause the air spring
characteristics to have a tendency
to be stiffer with the consequent
deteriorated performance and
characteristics. Therefore, adjust
the front fork within the specified
range.
Secondary reduction ratio =
Number of rear wheel sprocket
teeth/Number of drive sprocket
teeth
Standard secondary
reduction ratio49/13
(3.769)
* 51/13
(3.923)
* Except for USA and CDN
Part name Size Part number
Drive
sprocket "1"
(STD) 13T 9383B-13218
Rear wheel
sprocket "2"
47T 17D-25447-50
48T 17D-25448-50
(STD) 49T 17D-25449-50
50T 17D-25450-50
* (STD) 51T 17D-25451-50
52T 17D-25452-50
* Except for USA and CDN
Standard tire pressure:
100 kPa (1.0 kgf/cm
2,
15 psi)
Extent of adjustment:
60–80 kPa (0.6–0.8 kgf/
cm
2, 9.0–12 psi)
Extent of adjustment:
100–120 kPa (1.0–1.2
kgf/cm
2, 15–18 psi)
Standard oil amount:
350 cm3 (12.3 Imp oz,
11.8 US oz)
* 337 cm
3 (11.9 Imp oz,
11.4 US oz)
Extent of adjustment:
300–375 cm
3(10.6–13.2
Imp oz, 10.1–12.7 US
oz)
* Except for USA and CDN