2010 YAMAHA YZ250F ignition

CONTENTS
CHAPTER 1GENERAL
INFORMATION
LOCATION OF
IMPORTANT LABELS ..... 1-1
DESCRIPTION ................. 1-5
CONSUMER
INFORMATION................. 1-6
INCLUDED PARTS .......... 1-6
IMPORTANT
INFORMATION................. 1-6
CHECKING OF
CONNECTION .................. 1-7
SPECIAL TOOLS ............. 1-8
CONTROL
FUNCTIONS ................... 1-12
STARTING AND
BREAK-IN ...................... 1-13
TORQUE-CHECK
POINTS........................... 1-15
CLEANING AND
STORAGE ...................... 1-16
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
INSPECTION AND ADJUSTMENTS
MAINTENANCE
INTERVALS ...................... 3-1
PRE-OPERATION
INSPECTION AND
MAINTENANCE................ 3-5
ENGINE ............................ 3-6
CHASSIS ........................ 3-14
ELECTRICAL ................. 3-24
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 ....... 4-33
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 ....................5-31
REAR SHOCK
ABSORBER ....................5-36
CHAPTER 6
ELECTRICAL
ELECTRICAL
COMPONENTS AND
WIRING DIAGRAM ...........6-2
IGNITION SYSTEM...........6-3
THROTTLE POSITION
SENSOR SYSTEM ...........6-6
CHAPTER 7 TUNING
ENGINE.............................7-1
CHASSIS ..........................7-6

1-10
SPECIAL TOOLS
Timing light
YM-33277-A, 90890-03141 This tool is necessary for checking
ignition timing.
Valve spring compressor
YM-4019, 90890-04019 This tool is needed to remove and
install the valve assemblies.
Clutch holding tool
YM-91042, 90890-04086 This tool is used to hold the clutch
when removing or installing the
clutch boss securing nut.
Valve guide remover
Intake 4.0 mm (0.16 in)
Exhaust 4.5 mm (0.18 in)
YM-4111, 90890-04111
YM-4116, 90890-04116 This tool is needed to remove and
install the valve guide.
Valve guide installer
Intake 4.0 mm (0.16 in)
Exhaust 4.5 mm (0.18 in)
YM-4112, 90890-04112
YM-4117, 90890-04117 This tool is needed to install the
valve guide.
Valve guide reamer
Intake 4.0 mm (0.16 in)
Exhaust 4.5 mm (0.18 in)
YM-4113, 90890-04113
YM-4118, 90890-04118 This tool is needed to rebore the
new valve guide.
Tool name/Part number How to use Illustration

1-11
SPECIAL TOOLS
Dynamic spark tester
YM-34487
Ignition checker
90890-06754This instrument is necessary for
checking the ignition system compo-
nents.
Digital tachometer
YU-39951-B, 90890-06760 This tool is needed for observing en-
gine rpm.
YAMAHA Bond No. 1215 (Three-
Bond
® No. 1215)
90890-85505 This sealant (Bond) is used for
crankcase mating surface, etc.
Tool name/Part number
How to useIllustration

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, CDNEUROPE, 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 Bilateral beam←←
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

2-10
TIGHTENING TORQUES
ELECTRICAL
TIGHTENING TORQUES
ENGINE
△- marked portion shall be checked for torque ti ghtening after break-in or before each race.
Item StandardLimit
Ignition system: Advancer type Electrical----
CDI: Magneto-model (stator)/manufacturer 17D-50/YAMAHA----
Charging coil 1 resistance (color) 720–1,080 Ωat 20 °C (68 °F)
(Green–Brown) ----
Charging coil 2 resistance (color) 44–66 Ωat 20 °C (68 °F) (Black–Pink) ----
Pickup coil resistance (color) 248–372 Ωat 20 °C (68 °F) (White–Red) ----
CDI unit-model/manufacturer 17D-50/YAMAHA (For USA and CDN) ----
17D-60/YAMAHA (Except for USA and
CDN) ----
Ignition coil: Model/manufacturer 5UL-20/DENSO----
Minimum spark gap 6 mm (0.24 in)----
Primary coil resistance 0.08–0.10 Ωat 20 °C (68 °F) ----
Secondary coil resistance 4.6–6.8 kΩat 20 °C (68 °F) ----
Part to be tightened Thread size Q'tyTightening torque
Nm m•kg ft•lb
Spark plug M10S × 1.0 1 13 1.3 9.4
Camshaft cap M6 × 1.0 10 10 1.0 7.2
Cylinder head blind plug screw M12 × 1.0 1 28 2.8 20
Cylinder head (stud bolt) M6 × 1.0 2 7 0.7 5.1
Cylinder head (stud bolt) M8 × 1.25 1 15 1.5 11
Cylinder head (bolt) M9 × 1.25 4 38 3.8 27
Cylinder head (nut) M6 × 1.0 2 10 1.0 7.2
Cylinder head cover M6 × 1.0 2 10 1.0 7.2
Cylinder M6 × 1.0 1 10 1.0 7.2
Balancer weight M6 × 1.0 2 10 1.0 7.2
Balancer shaft driven gear M14 × 1.0 1 50 5.0 36
Timing chain guide (intake side) M6 × 1.0 2 10 1.0 7.2
Timing chain tensioner M6 × 1.0 2 10 1.0 7.2
Timing chain tensioner cap bolt M6 × 1.0 1 7 0.7 5.1
Impeller M8 × 1.25 1 14 1.4 10
Radiator hose clamp M6 × 1.0 10 2 0.2 1.4
Coolant drain bolt M6 × 1.0 1 10 1.0 7.2
Water pump housing M6 × 1.0 4 10 1.0 7.2
Radiator M6 × 1.0 6 10 1.0 7.2
Radiator pipe M6 × 1.0 1 10 1.0 7.2
Oil pump cover M4 × 0.7 1 1.7 0.17 1.2
Oil pump M6 × 1.0 3 10 1.0 7.2

2-20
CABLE ROUTING DIAGRAM
1. Sub-wire harness
2. Hot starter cable
3. Oil hose
4. Neutral switch lead
5. Radiator hose 2
6. Clamp
7. Ignition coil lead
8. CDI magneto lead
9. Neutral switch lead coupler
10. CDI unit lead coupler11. Radiator breather hose
12. Hot starter cable protector
13. Rubber cap
14. Throttle position sensor lead
15. Cylinder head breather hose
16. Throttle position sensor lead
coupler
17. Tension pipe
18. Radiator mounting boss
19. Cylinder head breather hose 20. Throttle position sensor tube
clamp
E
K
E
F
G H
H
F
I
J
A
A B
D
D
C J
C
G
B
K
E
M
M
H-H
K-K
E-E
D-D
M-M
F-F
A-A
I
L
L

2-21
CABLE ROUTING DIAGRAM
A. Pass the hot starter cable over the radiator mounting boss.
B. Pass the throttle position sensor lead under the hot starter cable.
C. Fasten the throttle position sen- sor lead and the hot starter ca-
ble.
D. Locate the clamp between the hot starter cable protector and
rubber cap.
E. Fasten the neutral switch lead below the oil hose. and pass the
neutral switch lead on the inside
of the oil hose.
F. Pass the neutral switch lead on the inside of the oil hose.
G. Fasten the neutral switch lead, CDI magneto lead, and radiator
breather hose onto the frame.
They should all be clamped
above the engine bracket to the
left of the downtube of the
frame. The clamp ends should
face backward and the rest out-
side of the frame.
H. Pass the clutch cable through the cable guide.
I. Pass the neutral switch lead and
CDI magneto lead behind the
frame.
J. Pass the hot starter cable on the
inside of the cylinder head
breather hose.
K. Fit the coupler projection into the
hole in the cover.
L. Fasten the sub-wire harness on the CDI unit bracket.
M. Fasten the sub-wire harness at the position-taped portion.
N. Pass each lead under the clamp. Locate the CDI magneto
lead on the outside of the igni-
tion coil lead. Locate the throttle
position sensor lead, neutral
switch lead, CDI magneto lead
and ignition coil lead so that they
do not lie one on another.
O. Fasten the sub-wire harness to
the CDI unit bracket with the
clamp ends located under the
bracket.
P. Fasten the neutral switch lead, throttle position sensor lead,
CDI magneto lead and ignition
coil lead. Fasten them around
the periphery of the recess be-
tween the tension pipe and radi-
ator mounting boss on the
frame.
Q. Locate the clamp ends within
the arrowed range. Assure that
the clamp end does not contact
the cylinder head breather hose. R. Pass the radiator breather hose
on the outside of the CDI mag-
neto lead and neutral switch
lead.
S. Fasten the throttle position sen- sor lead and hot starter cable.
Fasten them between the cylin-
der head breather hose and
throttle position sensor tube
clamp. Fasten the clamp with its
ends toward the right-side of the
frame and cut off the other end
with 3 to 5 clamp holes left in it.
T. Locate the radiator breather hose end above the down tube
and between the oil hose and
engine guard.
U. Fasten the neutral switch lead above the oil hose, and pass the
neutral switch lead on the inside
of the oil hose.

2-22
CABLE ROUTING DIAGRAM
1. Radiator hose 2
2. Radiator breather hose
3. Ignition coil
4. Throttle cable (pull)
5. Throttle cable (return)
6. Engine stop switch leadA. Put a cover over the ignition coil.
B. Pass the throttle cables through
the cable guide.
C. Pass the throttle cable over the radiator mounting boss. Cross
the throttle cable behind the ra-
diator.
D. Pass the throttle cables on the
outside of the ignition coil. E. Insert the engine stop switch
lead into the CDI unit band.
Align the coupler lower end with
the band lower end.
F. Fit the hole in the CDI unit band
over the CDI unit bracket.
C A
B B
A
C