YAMAHA YZ250F 2015 Manual Online

CABLE ROUTING DIAGRAM
2-38
1. Main harness
2. Radiator
3. Throttle position sensor lead
4. Joint coupler
5. Intake air temperature sensor lead
6. Intake air pressure sensor lead
7. Frame
8. Fuel hose
9. High tension cord
10. Spark plug cap
11. Cylinder head cover
12. Sub-wire harness
13. Injector coupler
14. Injector lead
15. Throttle body
16. Air filter case
17. ECU
18. Sub-wire harness coupler
A. Fix the main harness by the plastic clamp, and in-
sert the projection of the plastic clamp into the
hole in the sheet metal of the radiator.
B. Insert the projection of the main harness into the
hole in the frame.
C. To the sub-wire harness
D. Pass the high tension cord above the fuel hose.
E. ±10°
F. Install the spark plug cap with this facing the right
of the vehicle.
G. Push the spark plug cap home, where there shall
be no gap between it and the cylinder head cover.
H. Pass the injector lead to the top of the vehicle be-
yond the fuel hose.
I. Insert the coupler of the sub-wire harness into the
rib of the air filter case.
J. Pass the sub-wire harness between the ECU and
the air filter case.

CABLE ROUTING DIAGRAM
2-39

CABLE ROUTING DIAGRAM
2-40
1. Brake master cylinder
2. Brake hose holder
3. Brake hoses
A. While installing the brake hose, direct a bend in
its pipe portion as shown, and bring it into contact
with the projection on the brake caliper.
B. Pass the brake hose into the brake hose holders.
C. If the brake hose interferes with the rear shock
absorber, correct its twist.
D. While installing the brake hose, direct a bend in
its pipe portion as shown, and bring it into contact
with the projection on the brake master cylinder.

CABLE ROUTING DIAGRAM
2-41

3
PERIODIC CHECKS AND ADJUSTMENTS
MAINTENANCE INTERVALS.......................................................................... 3-1
MAINTENANCE INTERVALS .................................................................... 3-1
PRE-OPERATION INSPECTION AND MAINTENANCE................................. 3-7
GENERAL INSPECTION AND MAINTENANCE........................................ 3-7
ENGINE............................................................................................................ 3-8
CHECKING THE COOLANT LEVEL .......................................................... 3-8
CHECKING THE COOLING SYSTEM ....................................................... 3-8
CHANGING THE COOLANT...................................................................... 3-8
CHECKING THE RADIATOR CAP ............................................................ 3-9
CHECKING THE RADIATOR CAP OPENING PRESSURE ...................... 3-9
CHECKING THE COOLANT CIRCULATORY SYSTEM FOR LEAKS .... 3-10
ADJUSTING THE CLUTCH LEVER POSITION ...................................... 3-10
ADJUSTING THE CLUTCH LEVER FREE PLAY .................................... 3-10
ADJUSTING THE THROTTLE GRIP FREE PLAY .................................. 3-11
LUBRICATING THE THROTTLE CABLE ................................................ 3-12
CLEANING THE AIR FILTER ELEMENT................................................. 3-12
CHECKING THE THROTTLE BODY JOINT ............................................ 3-13
CHECKING THE BREATHER HOSES .................................................... 3-13
CHECKING THE EXHAUST SYSTEM..................................................... 3-13
CHECKING THE FUEL LINE ................................................................... 3-14
CHECKING THE ENGINE OIL LEVEL..................................................... 3-14
CHANGING THE ENGINE OIL ................................................................ 3-15
ADJUSTING THE ENGINE IDLING SPEED ............................................ 3-16
ADJUSTING THE VALVE CLEARANCE ................................................. 3-17
CHASSIS........................................................................................................ 3-21
BLEEDING THE BRAKE SYSTEM .......................................................... 3-21
CHECKING THE BRAKE HOSE .............................................................. 3-22
ADJUSTING THE FRONT BRAKE .......................................................... 3-22
ADJUSTING THE REAR BRAKE ............................................................. 3-23
CHECKING THE FRONT BRAKE PADS ................................................. 3-23
CHECKING THE REAR BRAKE PADS ................................................... 3-25
CHECKING THE REAR BRAKE PAD INSULATOR ................................ 3-26
CHECKING THE BRAKE FLUID LEVEL.................................................. 3-26
ADJUSTING THE DRIVE CHAIN SLACK ................................................ 3-27
CHECKING THE FRONT FORK LEGS ................................................... 3-28
CHECKING THE FRONT FORK PROTECTOR GUIDE .......................... 3-28
CLEANING THE FRONT FORK OIL SEAL AND DUST SEAL ................ 3-28
AIR BLEEDING FROM FRONT FORK .................................................... 3-28
ADJUSTING THE FRONT FORK LEGS .................................................. 3-29
CHECKING THE SWINGARM OPERATION ........................................... 3-30
CHECKING THE REAR SUSPENSION ................................................... 3-30
ADJUSTING THE REAR SHOCK ABSORBER ASSEMBLY ................... 3-30
CHECKING THE TIRES ........................................................................... 3-32
CHECKING AND TIGHTENING THE SPOKES ....................................... 3-32
CHECKING THE WHEELS ...................................................................... 3-33

CHECKING THE WHEEL BEARINGS ..................................................... 3-33
CHECKING AND ADJUSTING THE STEERING HEAD .......................... 3-33
LUBRICATING THE LEVERS .................................................................. 3-34
LUBRICATING THE PEDAL .................................................................... 3-34
ELECTRICAL SYSTEM.................................................................................. 3-35
CHECKING THE SPARK PLUG .............................................................. 3-35
CHECKING THE IGNITION TIMING ........................................................ 3-35

MAINTENANCE INTERVALS
3-1
EAS1SM5066
MAINTENANCE INTERVALS
EAS1SM5067MAINTENANCE INTERVALSECA@
NOTICE
• After a break-in or before each race, always check the points shown in “TORQUE-CHECK
POINTS” for tightening torques and retighten them. (“TORQUE-CHECK POINTS” on page 1-
25.)
• Periodic inspection is essential in making full use of the machine performance. The life of
parts varies significantly 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.
ITEMAfter
break-
inEvery
race
(about
2.5
hours)Every
third
(about
7.5
hours)Every
fifth
(about
12.5
hours)As re-
quiredRemarks
VALVE
Check the valve
clearancesThe engine must be cold.
Inspect Check the valve seats and the
valve faces for wear.
Replace
VALVE SPRING
Inspect Check the free length and the
tilt.
Replace
VALVE LIFTER
Inspect Check for scratches and wear.
Replace
CAMSHAFT Inspect the camshaft surface.
Inspect Inspect the decompression
system.
Replace
CAMSHAFT
SPROCKET
Inspect Check for wear on the teeth
and for damage.
Replace
PISTON
Inspect Inspect crack.
Clean Inspect carbon deposits and
eliminate them.
Replace Replace the piston, piston pin,
piston pin clip, and piston ring
all as a set.

MAINTENANCE INTERVALS
3-2
PISTON RING
Inspect Check the end gap of the pis-
ton ring.
Replace Replace the piston, piston pin,
piston pin clip, and piston ring
all as a set.
PISTON PIN
Inspect
Replace Replace the piston, piston pin,
piston pin clip, and piston ring
all as a set.
CYLINDER HEAD Check the coolant passages
for corrosion.
Inspect carbon deposits and
eliminate them.
Inspect and clean Check for warpage, and re-
place the gasket.
CYLINDER
Inspect and clean Inspect score marks.
Replace Inspect wear.
ENGINE OIL
Inspect Check the engine oil amount.
Replace
OIL FILTER ELE-
MENT
Replace
OIL STRAINER
Clean
CLUTCH
Inspect and adjust Inspect housing, friction plate,
clutch plate and spring.
Replace
TRANSMISSION
Inspect
Replace bearings
SHIFT FORK, SHIFT
CAM, GUIDE BAR
Inspect Inspect wear.ITEMAfter
break-
inEvery
race
(about
2.5
hours)Every
third
(about
7.5
hours)Every
fifth
(about
12.5
hours)As re-
quiredRemarks

MAINTENANCE INTERVALS
3-3
NUT (ROTOR)
Retighten Check for tightening torques.
EXHAUST PIPE, SI-
LENCER, PROTEC-
TOR
Inspect and re-
tightenCheck for exhaust leaks, and
tightening torques.
Clean
Replace fiver ** When the exhaust sound be-
comes louder or when a per-
formance drop is felt.
CRANKSHAFT
Inspect and clean
THROTTLE BODY
Inspect
AIR FILTER
Clean and lubri-
cateUse foam air-filter oil or equiv-
alent oil.
Replace
SPARK PLUG
Inspect and clean Check the electrodes and the
terminals for wear.
Replace
COOLING SYSTEM
Check coolant lev-
el and leakage
Check radiator cap
operationUse the radiator cap tester for
a checkup.
Check radiator cap
attached
Change the cool-
antEvery two years
Inspect hoses
ENGINE GUARD
Replace Breakage
FRAME
Clean and inspectITEMAfter
break-
inEvery
race
(about
2.5
hours)Every
third
(about
7.5
hours)Every
fifth
(about
12.5
hours)As re-
quiredRemarks

MAINTENANCE INTERVALS
3-4
FUEL TANK, FUEL
PUMP
Inspect
FUEL HOSE
Inspect
Replace Every four years
FRONT FORK LEG
(S)
Clean Dust seal
Inspect and adjust
Replace oil
Replace oil seal
Clean and grease
oil seals and dust
sealsLithium soap base grease
PROTECTOR
GUIDE
Replace
REAR SHOCK AB-
SORBER
Inspect and adjust
Lubricate(After
rain
ride)Grease pillow balls and bear-
ings.
Retighten Check for tightening torques.
BRAKE(S)
Adjust lever posi-
tion and pedal
height
Lubricate pivot
point
Check brake disc
surface
Check fluid level
and leakage
Retighten brake
disc bolts, caliper
bolts, master cylin-
der bolts and union
boltsCheck for tightening torques.
Replace padsITEMAfter
break-
inEvery
race
(about
2.5
hours)Every
third
(about
7.5
hours)Every
fifth
(about
12.5
hours)As re-
quiredRemarks