tow YAMAHA YZ250F 2016 Owners Manual

CONTROL FUNCTIONS
1-18
EAS1SM9029
CONTROL FUNCTIONS
EAS1SM9030ENGINE STOP SWITCH
The engine stop switch “1” is located on the left
handlebar. Continue pushing the engine stop
switch till the engine comes to a stop.
EAS1SM9031CLUTCH LEVER
The clutch lever “1” is located on the left han-
dlebar. The clutch lever disengages or engag-
es the clutch.
Pull the clutch lever toward the handlebar to
disengage the clutch, and release the lever to
engage the clutch.
EAS1SM9032SHIFT PEDAL
The shift pedal “1” has adopted a method of 1
down & 4 ups (press-down & kick-ups).
Press it down for N (neutral) to 1st, and kick it
up for 2nd to 5th.
EAS1SM9033KICKSTARTER LEVER
The kickstarter lever “1” is in the right of the
chassis.
To start the engine, pull out and push down the
kickstarter lever with your foot.
EAS1SM9034THROTTLE GRIP
The throttle grip “1” is located on the right han-
dlebar. The throttle grip accelerates or deceler-
ates the engine. For acceleration, turn the grip
toward you; for deceleration, turn it away from
you.
EAS1SM9035FRONT BRAKE LEVER
The front brake lever “1” is located on the right
handlebar. Pull it toward the handlebar to acti-
vate the front brake.
1
1

CONTROL FUNCTIONS
1-19
EAS1SM9036REAR BRAKE PEDAL
The rear brake pedal “1” is in the right of the
chassis. Press down on the brake pedal to ac-
tivate the rear brake.
EAS1SM9037STARTER KNOB/IDLE ADJUSTING SCREW
Starting a cold engine requires a larger amount
of intake air, which is supplied by the starter
knob/idle screw “1”.
Pulling the knob toward “a” turns ON the start-
er, resulting in a larger amount of intake air.
Pushing the knob toward “b” turns OFF the
starter.
EWA
WARNING
While handling the starter knob/idle screw,
take care not to burn yourself on exhaust
pipes.
EAS1SM9038FUEL TANK CAP
Fuel tank cap “1” is located under the fuel tank
cap cover “2”.
Remove the fuel tank cap cover to open the fuel
tank cap.
TIP
• To remove the fuel tank cap cover, insert fin-
gers under part “a”, and then use both hands
to lift it up towards the rear of the vehicle.
• Install the fuel tank cap cover after placing the
bands “3” all the way in under the seat.
1
ab1
1
23
a
2

CLEANING AND STORAGE
1-25
EAS1SM9047
CLEANING AND STORAGE
EAS1SM9048CLEANING
Frequent cleaning of your vehicle will enhance
its appearance, maintain performance, and ex-
tend the life of parts.
1. Before cleaning, block the silencer outlet to
prevent water from entering. A plastic bag
secured with a rubber band may be used for
this purpose.
2. If the engine is contaminated with oil, apply
some degreaser to it with a brush. Do not
apply degreaser to the drive chain, the
sprockets, or the wheel axles.
3. Hose off dirt. Use only enough water pres-
sure to do the job.
ECA
NOTICE
Do not use high-pressure washers or steam
cleaners. Otherwise, these may cause a fail-
ure because of the entry of water.
4. After hosing off the dirt, wash all surfaces
with a mild detergent and warm water. Use
a toothbrush to clean hard-to-reach places.
5. Rinse the detergent with clean water, and
dry the surfaces with a soft towel or a cloth.
6. Immediately after cleaning, remove any wa-
ter from the drive chain with a paper towel,
and lubricate it to prevent rust.
7. Clean the seat with a vinyl upholstery clean-
er to keep the cover pliable and glossy.
8. Automotive wax may be applied to all paint-
ed or chromed surfaces. Avoid using such
wax as contains abrasives, because it may
scratch surfaces.
9. After completing the above, start the engine
and allow it to warm up for several minutes.
EAS1SM9049STORAGE
If your vehicle is to be stored for 60 days or
more, some preventive measures must be tak-
en to avoid deterioration. After cleaning the ve-
hicle thoroughly, prepare it for storage as
follows:
1. Fill the fuel tank with gasoline.
2. Remove the spark plug, pour a spoonful of
engine oil (SAE 10W-40) into the spark plug
hole, and reinstall the plug. With the engine
stop switch pushed in, by pushing down the
kickstarter lever, crank the engine to coat
the cylinder walls with oil.3. Remove the drive chain, clean it thoroughly
with solvent, and lubricate it Reinstall the
drive chain or store it in a plastic bag tied to
the frame.
4. Lubricate all cables.
5. Lift up the frame of the vehicle to keep the
wheels off the ground.
6. Tie a plastic bag over the muffler outlet to
prevent moisture from entering.
7. If the vehicle is to be stored in a place that is
humid or exposed to the sea breeze, apply a
light coat of oil to metal surfaces. Do not ap-
ply oil to the seat or rubber parts.
TIP
Make any necessary repairs before the vehicle
is stored.

CABLE ROUTING DIAGRAM
2-32
1. Clutch cable
2. Throttle cable (pull)
3. Throttle cable (return)
4. Cable holder
5. Engine stop switch lead
6. Frame
7. Coupler for connecting optional part
8. Bracket
9. Engine stop switch coupler
10. Rectifier/regulator coupler
11. Starter knob/idle screw
12. Neutral switch lead
13. Crankcase cover
14. AC magneto lead
15. Front engine bracket
16. Radiator hose
17. Coupler cover
18. Tension arm
19. Rectifier/regulator lead
20. Main harness
21. Tank rail
22. Radiator
23. Cylinder head breather hose
24. Radiator breather hose
25. Down tube
26. Crankcase
A. Pass the engine stop switch lead between the
frame and the cable holder.
B. Pass the engine stop switch lead between the
coupler for connecting optional part and the
frame, where the main harness should face the
outside of the vehicle.
C. Insert the coupler for connecting optional part into
the connector, and fix it to the bracket.
D. Insert and fix the engine stop switch coupler to
the bracket.
E. Insert and fix the rectifier/regulator coupler to the
bracket.
F. Pass the AC magneto lead to the front of the ve-
hicle beyond the starter knob/idle screw and to
the rear of the vehicle beyond the radiator. No
pinch is allowed between the radiator and the
tension arm.
G. 70 mm (2.76 in)
H. Bring the neutral switch lead into line with the
crankcase cover with no sag allowed.
I. Bring the AC magneto lead into line with the
clutch cable with no sag allowed.
J. Pass the neutral switch lead to the inside of the
front engine bracket (the side of the vehicle).
K. Clamp the clutch cable and the AC magneto lead
by the plastic locking tie. Regardless of the orien-
tation of the lock on the plastic locking tie, cut the
end.
L. Pass the clutch cable with no downward sag al-
lowed.
M. Bring the grommet of the clutch cable into contact
with the radiator hose, and pass it to the outside
of the neutral switch lead and the AC magneto
lead (the outside of the vehicle).
N. 40 mm (1.57 in)
O. Clamp the clutch cable, the AC magneto lead,
and the neutral switch lead by the plastic locking
tie. Make sure that they are clamped at the posi-
tioning tape in the clutch cable. Make the lock on
the plastic locking tie face the front of the vehicle,
and cut the end.
P. After connecting the neutral switch coupler, at-
tach the coupler cover.
Q. After connecting the AC magneto coupler, attach
the coupler cover.R. Pass the rectifier/regulator lead to the inside of
the tension arm (the side of the vehicle).
S. Pass the main harness to the front of the radiator
hose (the front of the vehicle), and to the inside of
the clutch cable (the side of the vehicle).
T. Pass the engine stop switch lead between the
coupler for connecting optional part and the tank
rail, with the lead on the main harness side facing
the top of the vehicle.
U. Pass the radiator breather hose between the
down tubes.
V. Clamp the radiator breather hose, above the en-
gine bracket (front). Clamp the lock on the plastic
tie with it located outside the vehicle, and face the
end toward the front of the vehicle.
W. Clamp the clutch cable at the front of the lead (the
front of the vehicle).
X. Make the lock on the plastic locking tie face the
front of the vehicle, and insert the projection into
the hole in the frame. Cut the end of the plastic
locking tie.

CABLE ROUTING DIAGRAM
2-34
1. Bracket
2. Condenser
3. Coolant temperature sensor
4. Coupler cover
5. Intake air temperature sensor coupler
6. Intake air temperature sensor coupler
7. Radiator hoses
8. Radiator breather hose
9. Joint coupler
10. Plate
11. Tension arm
12. Throttle position sensor lead
13. Ground lead
14. Throttle position sensor coupler
15. Radiator breather hose
16. Cylinder head breather hose
17. Engine guard
18. Crankcase
19. Fuel pump coupler
20. Fuel hose
21. Condenser lead
22. Fuel pump lead
23. Condenser coupler
24. Ground lead terminal
25. Fuel tank
26. Damper
27. Rear frame
28. Main harness
A. Insert the condenser into the bracket as far as it
will go.
B. Attach the coupler cover to the coolant tempera-
ture sensor coupler.
C. Pass the radiator breather hose to the inside of
the radiator hose (the side of the vehicle).
D. Insert and fix the joint coupler to the plate. After
fixing it, attach the cover.
E. Pass the throttle position sensor lead to the out-
side of the tension arm (the outside of the vehi-
cle).
F. After connecting the throttle position sensor cou-
pler, attach the cover.
G. Pass the radiator breather hose to the outside of
the tension arm and the throttle position sensor
lead (the outside of the vehicle), and to the inside
of the radiator hose (the side of the vehicle).
H. Pass the protector of the cylinder head breather
hose until it touches the holder.
I. Pass the cylinder head breather hose between
the engine guard and the crankcase.
J. Install the end of the cylinder head breather hose
with it facing downward.
K. After connecting the fuel pump coupler, attach
the coupler cover.
L. 55 mm (2.17 in) (seat load receiver)
M. Clamp the fuel hose and the fuel pump lead by
the holder. Make sure that the painted part on the
fuel hose is clamped, and face the lock on the
clamp toward the rear top of the vehicle.
N. Do not install the plastic locking tie to the seat
load receiver.
O. Make the lock on the plastic locking tie face the
front of the vehicle, and make the end face the
bottom of the vehicle. Do not cut the end.
P. Install the ground lead terminal between the plate
and the bolt.
Q. Detent
R. Fix the ground lead terminal to the detent in the
plate. For the ground lead terminal, either side
will do.S. Insert the projection on the plastic locking tie into
the hole in the rear frame.
T. Clamp the painted part on the fuel hose by the
plastic clamp. Make the lock on the plastic clamp
face the bottom of the vehicle, and cut the end.

FRONT BRAKE
4-19
3. Install:
• Spring “1”
Install to the brake master cylinder piston
“2”.
TIP
Install the spring with a smaller inside diameter
to the brake master cylinder piston.
4. Install:
• Brake master cylinder kit “1”
• Washer “2”
• Circlip “3”
• Dust boot “4”
• Push rod “5”
TIP
• Before installation, apply brake fluid to the
brake master cylinder kit.
• Before installation, apply silicone grease to
the push rod end.
• Use circlip pliers to install the circlip.
EAS1SM9145INSTALLING THE FRONT BRAKE MASTER
CYLINDER
1. Install:
• Brake master cylinder “1”
TIP
• Install the front brake master cylinder holder
with the “UP” mark facing up.
• First, tighten the upper bolt, then the lower
bolt.
2. Install:
• Copper washers
• Brake hose
• Union bolt
EWA13530
WARNING
Proper brake hose routing is essential to in-
sure safe vehicle operation.
ECA1DX1007
NOTICE
During installation, bring the brake hose
into contact with the brake master cylinder
projection “a” and make its bent portion “b”
face downward.
TIP
Turn the handlebar toward right and left to
make sure that the brake hose does not touch
other parts (e.g., wire harness, cables, leads).
Adjust if necessary.
2 1
3
New
New
Brake master cylinder holder bolt
9 Nm (0.9 m·kgf, 6.5 ft·lbf)
Brake hose union bolt
30 Nm (3.0 m·kgf, 22 ft·lbf)
T R..
New
T R..

ENGINE REMOVAL
5-7
EAS1SM9198REMOVING THE ENGINE
1. Remove:
• Pivot shaft “1”
TIP
If the pivot shaft is pulled all the way out, the
swingarm will come loose. If possible, insert a
shaft of similar diameter into the other side of
the swingarm to support it.
2. Remove:
• Engine “1”
From the right side.
TIP
• Make sure that the couplers, the hoses, and
the cables are disconnected.
• Lift up the engine, and remove this from its
lower part toward the right of the chassis.
EAS1SM9199CHECKING THE SILENCER AND EXHAUST
PIPE
1. Check:
•Gasket “1”
Damage  Replace.
EAS1SM9200CHANGING THE SILENCER FIBER
1. Remove:
•Bolt “1”
• Silencer body “2”
ECANOTICE
Do not hit the silencer stay “a” as it may do
damage to the silencer.
TIP
Remove the inner pipe while holding the silenc-
er in place with a vise etc.
2. Remove:
•Rivet “1”
• Silencer cap “2”
1
1
1
a
1
2
2
1

KICKSTATER
5-46
3. Install:
•Transmission
TIP
Slide the spring guide into the kick shaft, make
sure the groove “a” in the spring guide fits on
the stopper of the torsion spring.
4. Install:
• Kick shaft assembly “1”
TIP
• Before installation, apply molybdenum disul-
fide grease to the contacting surfaces of the
kick shaft ratchet wheel guide “2” and the kick
shaft stopper “a”.
• Apply the engine oil on the kick shaft.
• Slide the kick shaft assembly into the crank-
case and make sure the kick shaft stopper “a”
fits into the kick shaft ratchet wheel guide.5. Install:
• Torsion spring “1”
TIP
Turn the torsion spring clockwise and hook into
the proper hole “a” in the crankcase.
EAS1SM9251INSTALLING THE KICK IDLE GEAR
1. Install:
• Kick idle gear “1”
• Washer “2”
• Circlip “3”
TIP
• Apply the engine oil on the kick idle gear inner
circumference.
• Install the kick idle gear with its depressed
side “a” toward you.
1 2a b
New

CHASSIS
10-1
EAS1SM9366
CHASSIS
EAS1SM9367SELECTION OF THE SECONDARY REDUC-
TION RATIO (SPROCKET)
reduction ratio>
• It is generally said that the secondary gear ra-
tio should be reduced for a longer straight por-
tion of a speed course and should be
increased for a course with many corners. Ac-
tually, 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 ma-
chine suitable for the entire course.
• In actuality, it is very difficult to achieve set-
tings suitable for the entire course and some
settings may be sacrificed. Thus, the settings
should be matched to the portion of the
course that has the greatest effect 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, determine the second-
ary reduction ratio.
• If a course has a long straight portion where a
machine can run at maximum speed, the ma-
chine is generally set such that it can develop
its maximum revolutions toward the end of the
straight line, with care taken to avoid the en-
gine over-revving.
TIP
Riding technique varies from rider to rider and
the performance of a machine also vary from
machine to machine. Therefore, do not imitate
other rider’s settings from the beginning but
choose your own setting according to the level
of your riding technique.
EAS1SM9368DRIVE AND REAR WHEEL SPROCKETS
SETTING PARTS
Secondary reduction ratio = Number of
rear wheel sprocket teeth/Number of
drive sprocket teeth
Secondary reduction ratio
3.846 (50/13)
Part name Type Part number
Drive sprocket “1”
(STD) 13T 9383B-13218
Rear wheel
sprocket “2”
47T 17D-25447-50
48T 17D-25448-50
49T 17D-25449-50
(STD) 50T 17D-25450-50
51T 17D-25451-50
52T 17D-25452-50

CHASSIS
10-6
EAS1SM9378SUSPENSION SETTING (FRONT FORK)
TIP
• If any of the following symptoms is experienced with the standard position as the base, make reset-
ting by reference to the adjustment procedure given in the same chart.
• Before any change, set the rear shock absorber sunken length to the standard figure 90–100 mm
(3.5–3.9 in).
SymptomSection
Check Adjust
JumpLarge
gapMedi-
um
gapSmall
gap
Stiff over entire
rangeCompression
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.
Oil amount Decrease oil amount by about
5–10 cm
3 (0.2–0.3 US oz, 0.2–
0.4 Imp.oz).
Spring Replace with soft spring.
Unsmooth
movement over
entire rangeOuter tube
Inner tubeCheck for any bends, dents,
other noticeable scars, etc. If
any, replace affected parts.
Slide metal Replace with a new one for ex-
tended use.
Piston metal Replace with a new one for ex-
tended use.
Lower bracket
tightening
torqueRetighten to specified torque.
Poor initial
movementRebound
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.
Oil seals Apply grease in oil seal wall.
Soft over entire
range, bottom-
ing outCompression
damping forceTurn adjuster clockwise (about
2 clicks) to increase damping.
Oil amount Increase oil amount by about
5–10 cm
3 (0.2–0.3 US oz, 0.2–
0.4 Imp.oz).
Spring Replace with stiff spring.
Stiff toward
stroke endOil amountDecrease oil amount by about
5 cm
3 (0.2 US oz, 0.2 Imp.oz).
Soft toward
stroke end, bot-
toming outOil amountIncrease oil amount by about 5
cm
3 (0.2 US oz, 0.2 Imp.oz).
Stiff initial
movementCompression
damping forceTurn adjuster counterclock-
wise (about 2 clicks) to de-
crease damping.