2014 YAMAHA WR 250F stop start

2-13
TIGHTENING TORQUES
Throttle cable adjust bolt and locknut M6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Throttle cable (pull) M6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Throttle cable (return) M12 1 11 Nm (1.1 m•kg, 8.0 ft•lb)
Throttle cable cover M5 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Hot starter plunger M12 1 2 Nm (0.2 m•kg, 1.4 ft•lb)
Hot starter cable adjust bolt and locknut M6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
△Air filter case M6 2 8 Nm (0.8 m•kg, 5.8 ft•lb)
Air filter joint and air filter case M5 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Exhaust pipe M8 2 20 Nm (2.0 m•kg, 14 ft•lb)
△Exhaust pipe protector M6 3 10 Nm (1.0 m•kg, 7.2 ft•lb)
△Silencer M8 2 30 Nm (3.0 m•kg, 22 ft•lb)
Silencer clamp M8 1 16 Nm (1.6 m•kg, 11 ft•lb)
Spark arrester M5 4 7 Nm (0.7 m•kg, 5.1 ft•lb)
Silencer cap M5 6 5 Nm (0.5 m•kg, 3.6 ft•lb)
Air induction pipe M6 1 10 Nm (1.0 m•kg, 7.2 ft•lb)
Air induction pipe clamp M6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Air cut-off valve assembly and bracket M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Bracket (air cut-off valve) and frame M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
Crankcase M6 11 12 Nm (1.2 m•kg, 8.7 ft•lb)
Crankcase bearing stopper M6 11 10 Nm (1.0 m•kg, 7.2 ft•lb)
Crankcase bearing stopper (crankshaft) M6 4 14 Nm (1.4 m•kg, 10 ft•lb) Stake.
Left crankcase cover M6 8 10 Nm (1.0 m•kg, 7.2 ft•lb)
Idle gear cover (starter motor)M6 3 10 Nm (1.0 m•kg, 7.2 ft•lb)
Idle gear plate M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Right crankcase cover M6 6 10 Nm (1.0 m•kg, 7.2 ft•lb)
Clutch cover M6 7 10 Nm (1.0 m•kg, 7.2 ft•lb)
Crankcase oil drain bolt M10 1 20 Nm (2.0 m•kg, 14 ft•lb)Copper
washer
△Crankshaft end accessing screw M32 1 —
△Timing mark accessing screw M14 1 —
Drive chain sprocket cover M6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
Kick shaft ratchet wheel guide M6 2 12 Nm (1.2 m•kg, 8.7 ft•lb) Lock washer
Kickstarter lever M8 1 33 Nm (3.3 m•kg, 24 ft•lb)
Primary drive gear M18 1 75 Nm (7.5 m•kg, 54 ft•lb) Lock washer
Clutch spring M6 5 10 Nm (1.0 m•kg, 7.2 ft•lb)
Clutch boss M16 1 75 Nm (7.5 m•kg, 54 ft•lb) Lock washer
Clutch cable locknut M8 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
Push lever shaft M6 1 10 Nm (1.0 m•kg, 7.2 ft•lb)
Drive sprocket M18 1 75 Nm (7.5 m•kg, 54 ft•lb) Lock washer
Drive axle oil seal stopper M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Segment M8 1 30 Nm (3.0 m•kg, 22 ft•lb)
Shift guide M6 2 10 Nm (1.0 m•kg, 7.2 ft•lb)
Stopper lever M6 1 10 Nm (1.0 m•kg, 7.2 ft•lb)
Shift pedal M6 1 12 Nm (1.2 m•kg, 8.7 ft•lb)ItemThread
sizeQ'ty Tightening torque Remarks

2-14
TIGHTENING TORQUES
CHASSIS
△- marked portion shall be checked for torque tightening after break-in or before each race.
ItemThread
sizeQ'ty Tightening torque Remarks
△Upper bracket and outer tube M84 21 Nm (2.1 m•kg, 15 ft•lb)
△Lower bracket and outer tube M8 4 21 Nm (2.1 m•kg, 15 ft•lb)
△Upper bracket and steering stem M24 1 145 Nm (14.5 m•kg, 105 ft•lb)
△Handlebar upper holder and handlebar
lower holderM8 4 28 Nm (2.8 m•kg, 20 ft•lb)
△Handlebar lower holder and upper brack-
etM10 2 34 Nm (3.4 m•kg, 24 ft•lb)
△Steering stem and steering ring nut M28 1 Refer to TIP.
Front fork and front fork cap bolt M51 2 30 Nm (3.0 m•kg, 22 ft•lb)
Front fork and base valve M30 2 55 Nm (5.5 m•kg, 40 ft•lb)Copper
washer
Front fork cap bolt and damper rod M12 2 29 Nm (2.9 m•kg, 21 ft•lb)
Front fork bleed screw and front fork cap
boltM5 2 1 Nm (0.1 m•kg, 0.7 ft•lb)
△Front fork and front fork protector M6 6 7 Nm (0.7 m•kg, 5.1 ft•lb)
△Front fork protector and brake hose hold-
erM6 2 7 Nm (0.7 m•kg, 5.1 ft•lb)
Throttle grip cap M5 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Start switch M3 1 0.5 Nm (0.05 m•kg, 0.36 ft•lb)
Engine stop switch M3 1 0.5 Nm (0.05 m•kg, 0.36 ft•lb)
△Front brake master cylinder M6 29 Nm (0.9 m•kg, 6.5 ft•lb)
Brake lever mounting bolt M6 1 6 Nm (0.6 m•kg, 4.3 ft•lb)
Brake lever mounting nut M6 1 6 Nm (0.6 m•kg, 4.3 ft•lb)
Brake lever position locknut M6 1 5 Nm (0.5 m•kg, 3.6 ft•lb)
△Front brake hose guide and front brake
hose guide bracketM5 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
△Front brake hose guide and lower bracket M6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Clutch lever holder M5 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Clutch lever mounting nut M6 1 4 Nm (0.4 m•kg, 2.9 ft•lb)
Hot starter lever holder M5 2 4 Nm (0.4 m•kg, 2.9 ft•lb)
Hot starter lever mounting nut M5 1 2 Nm (0.2 m•kg, 1.4 ft•lb)
Front brake master cylinder cap M4 2 2 Nm (0.2 m•kg, 1.4 ft•lb)
△
Front brake hose union bolt M10 2 30 Nm (3.0 m•kg, 22 ft•lb)Copper
washer
△Front brake caliper M8 2 23 Nm (2.3 m•kg, 17 ft•lb)
△Front brake caliper and brake hose holder M6 1 10 Nm (1.0 m•kg, 7.2 ft•lb)
Pad pin plug M10 2 3 Nm (0.3 m•kg, 2.2 ft•lb)
△Front brake caliper and pad pin M10 1 18 Nm (1.8 m•kg, 13 ft•lb)
△Rear brake caliper and pad pin M10 1 18 Nm (1.8 m•kg, 13 ft•lb)
△Brake caliper and bleed screw M8 2 6 Nm (0.6 m•kg, 4.3 ft•lb)
△Front wheel axle and axle nut M16 1 90 Nm (9.0 m•kg, 65 ft•lb)
△Front wheel axle holder M8 4 21 Nm (2.1 m•kg, 15 ft•lb)

2-27
CABLE ROUTING DIAGRAM
1. Throttle cable
2. Clamp
3. Brake hose
4. Clutch cable
5. Hose guide
6. Main switch coupler
7. Wire harness
8. Headlight coupler
9. Hot starter cable
10. Multi-function display bracket
11. Main switch12. Upper bracket
13. Clutch switch coupler
14. Engine stop switch coupler
15. Multi-function display coupler
16. Start switch coupler
17. Speed sensor coupler
18. Speed sensor lead

2-28
CABLE ROUTING DIAGRAM
A. Fasten the start switch lead to
the handlebar with the plastic
bands.
B. Fasten the engine stop switch
lead and clutch switch lead to
the handlebar with the plastic
bands.
C. Pass the brake hose through
the hose guides.
D. Secure the coupler by inserting
it into the multi-function display
bracket.
E. Pass the throttle cables, clutch
cable and hot starter cable be-
tween the upper bracket and
multi-function display bracket.
F. Fasten the multi-function display
leads to the bracket. Cut off the
tie end.
G. Secure the coupler by pushing it
into the hole in the multi-function
display bracket.
H. Secure the wire harness clip by
pushing it into the hole in the
multi-function display bracket on
the inside.
I. Fasten the wire harness to the
multi-function display bracket.
Cut off the tie end.
J. Fasten the main switch lead
(wire harness side) to the multi-
function display bracket. Locate
the clamp end facing toward the
lower side of the frame and cut
off the tie end.
K. Pass the speed sensor lead
through the guide on the outside
of the front fork.

3-14
ENGINE
ADJUSTING THE PILOT SCREW
(For EUROPE)
1. Adjust:
• Pilot screw "1"
Adjustment steps:
To optimize the fuel flow at a smaller
throttle opening, each machine's pilot
screw has been individually set at the
factory. Before adjusting the pilot
screw, turn it in fully and count the
number of turns. Record this number
as the factory-set number of turns
out.
a. Turn in the pilot screw until it is
lightly seated.
b. Turn out the pilot screw by the
factory-set number of turns.
ADJUSTING THE ENGINE IDLING
SPEED
1. Start the engine and thoroughly
warm it up.
2. Adjust:
• Engine idling speed
Adjustment steps:
a. Turn the throttle stop screw "1"
until the specified engine idling
speed.
Using a digital engine tachometer for
idle speed adjustment, detect the en-
gine idling speed by bringing the
sensing element "c" of the engine ta-
chometer close to the ignition coil "2".
ADJUSTING THE VALVE
CLEARANCE
This section is intended for those who
have basic knowledge and skill con-
cerning the servicing of Yamaha mo-
torcycles (e.g., Yamaha dealers,
service engineers, etc.) Those who
have little knowledge and skill con-
cerning servicing are requested not to
undertake inspection, adjustment,
disassembly, or reassembly only by
reference to this manual. It may lead
to servicing trouble and mechanical
damage.
• The valve clearance should be ad-
justed when the engine is cool to
the touch.
• The piston must be at Top Dead
Center (T.D.C.) on compression
stroke to check or adjust the valve
clearance.
1. Remove:
•Seat
•Fuel tank
Refer to "SEAT, FUEL TANK
AND SIDE COVERS" section.
2. Drain:
• Coolant
Refer to "CHANGING THE
COOLANT" section.
3. Remove:
• Right radiator
Right to "RADIATOR" section in
the CHAPTER 5.
• Carburetor
Refer to "CARBURETOR" section
in the CHAPTER 5.
• Spark plug
• Upper engine bracket
• Cylinder head cover
Refer to "CAMSHAFTS" section
in the CHAPTER 5.4. Remove:
• Timing mark accessing screw "1"
• Crankshaft end accessing screw
"2"
• O-ring
5. Check:
• Valve clearance
Out of specification→Adjust.
Checking steps:
a. Turn the crankshaft counterclock-
wise with a wrench.
b. Align the T.D.C. mark "a" on the
rotor with the align mark "b" on the
crankcase cover when piston is at
T.D.C. on compression stroke.
In order to be sure that the piston is at
Top Dead Center, the punch mark "c"
on the exhaust camshaft and the
punch mark "d" on the intake cam-
shaft must align with the cylinder
head surface, as shown in the illustra-
tion.
c. Measure the valve clearance "e"
using a feeler gauge "1".
Record the measured reading if the
clearance is incorrect.
Pilot screw (example):
2 turns out
To increase idle speed→Turn the
throttle stop screw "1" in "a".
To decrease idle speed→Turn the
throttle stop screw "1" out "b".
Engine idling speed:
1,750–1,950 r/min
Valve clearance (cold):
Intake valve:
0.10–0.15 mm
(0.0039–0.0059 in)
Exhaust valve:
0.17–0.22 mm
(0.0067–0.0087 in)

4-1
ENGINE
TUNING
ENGINE
CARBURETOR SETTING
• The air/fuel mixture will vary de-
pending on atmospheric conditions.
Therefore, it is necessary to take
into consideration the air pressure,
ambient temperature, humidity,
etc., when adjusting the carburetor.
• Perform a test run to check for prop-
er engine performance (e.g., throt-
tle response) and spark plug(-s)
discoloration or fouling. Use these
readings to determine the best pos-
sible carburetor setting.
It is recommended to keep a record of
all carburetor settings and external
conditions (e.g., atmospheric condi-
tions, track/surface conditions, lap
times) to make future carburetor set-
ting easier.
• The carburetor is a part of the
fuel line. Therefore, be sure to in-
stall it in a wellventilated area,
away from flammable objects
and any sources of fire.
• Never look into the carburetor in-
take. Flames may shoot out from
the pipe if the engine backfires
while it is being started. Gasoline
may be discharged from the ac-
celerator pump nozzle when the
carburetor has been removed.
• The carburetor is extremely sen-
sitive to foreign matter (dirt,
sand, water, etc.). During instal-
lation, do not allow foreign mat-
ter to get into the carburetor.
• Always handle the carburetor
and its components carefully.
Even slight scratches, bends or
damage to carburetor parts may
prevent the carburetor from
functioning correctly. Carefully
perform all servicing with the ap-
propriate tools and without ap-
plying excessive force.
• When the engine is stopped or
when riding at no load, do not
open and close the throttle un-
necessarily. Otherwise, too
much fuel may be discharged,
starting may become difficult or
the engine may not run well.• After installing the carburetor,
check that the throttle operates
correctly and opens and closes
smoothly.
ATMOSPHERIC CONDITIONS AND
CARBURETOR SETTINGS
The air density (i.e., concentration of
oxygen in the air) determines the rich-
ness or leanness of the air/fuel mix-
ture.
• Higher temperature expands the air
with its resultant reduced density.
• Higher humidity reduces the
amount of oxygen in the air by so
much of the water vapor in the
same air.
• Lower atmospheric pressure (at a
high altitude) reduces the density of
the air.
EFFECT OF SETTING PARTS IN
RELATION TO THROTTLE VALVE
OPENING
A. Closed
B. Fully open
1. Pilot jet
2. Throttle valve cutaway
3. Jet needle
4. Main jetCONSTRUCTION OF
CARBURETOR AND SETTING
PARTS
The FLATCR carburetor has a prima-
ry main jet. This type of main jet is
perfect for racing machines since it
supplies an even flow of fuel, even at
full load. Use the main jet and the jet
needle to set the carburetor.
1. Jet needle
2. Pilot air jet
3. Needle jet
4. Main jet
5. Pilot jet
ADJUSTING THE MAIN JET
The richness of the air-fuel mixture at
full throttle can be set by changing the
main jet "1".
If the air-fuel mixture is too rich or too
lean, the engine power will drop, re-
sulting in poor acceleration.
Effects of changing the main jet
(reference)
A. Idle
B. Fully open
1. #180
2. #160
3. #170 Air
tem
p.Hu-
midi-
tyAir
pres-
sure
(alti-
tude)Mix-
tureSet-
ting
High HighLow
(high)Rich-
erLean-
er
Low LowHigh
(low)Lean-
erRich-
er
Standard main jet#160
* #170
* For AUS, NZ and ZA

5-8
CARBURETOR
e. If both are fine, adjust the float
height by bending the float tab "b"
on the float.
f. Recheck the float height.
CHECKING THE FLOAT
1. Inspect:
• Float "1"
Damage→Replace.
CHECKING THE STARTER
PLUNGER
1. Inspect:
• Cold starter plunger "1"
• Hot starter plunger "2"
Wear/damage→Replace.
CHECKING THE ACCELERATOR
PUMP
1. Inspect:
• Diaphragm (accelerator pump)
"1"
• Spring (accelerator pump) "2"
• Accelerator pump cover "3"
• O-ring "4"
• Push rod "5"
Tears (diaphragm)/damage→Re-
place.
Dirt→Clean.2. Inspect:
• Throttle shaft "1"
• Spring "2"
• Lever 1 "3"
• Spring 1 "4"
• Lever 2 "5"
• Spring 2 "6"
Dirt→Clean.
CHECKING THE AIR CUT VALVE
1. Inspect:
• Diaphragm (air cut valve) "1"
• Spring (air cut valve) "2"
• Air cut valve cover "3"
• O-ring "4"
Tears (diaphragm)/damage→Re-
place.
ASSEMBLING THE CARBURETOR
1. Install:
• Cold starter plunger "1"
2. Install:
•Pilot air jet "1"
• Main air jet "2"
3. Install:
• Spring 1 "1"
• Lever 1 "2"
To lever 2 "3".
Make sure the spring 1 fits on the
stopper "a" of the lever 2.
4. Install:
• Spring 2 "1"
To lever 2 "2".
5. Install:
• Push rod link lever assembly "1"
Make sure the stopper "a" of the
spring 2 fits into the recess "b" in the
carburetor.
6. Install:
• Washer "1"
• Circlip "2"
7. Install:
• Spring "1"
To throttle shaft "2".
Install the bigger hook "a" of the
spring fits on the stopper "b" of the
throttle shaft pulley.

5-9
CARBURETOR
8. Install:
• Throttle shaft assembly "1"
• Washer (metal) "2"
• Washer (resin) "3"
• Valve lever "4"
• Apply the fluorochemical grease on
the bearings.
• Fit the projection "a" on the throttle
shaft assembly into the slot "b" in
the throttle position sensor.
• Make sure the stopper "c" of the
spring fits into the recess in the car-
buretor.
• Turn the throttle shaft assembly left
while holding down the lever 1 "5"
and fit the throttle stop screw tip "d"
to the stopper "e" of the throttle
shaft assembly pulley.
9. Install:
• Push rod "1"
While holding down the lever 1 "2", in-
sert the push rod farthest into the car-
buretor.
10. Install:
• Starter jet "1"
• Pilot jet "2"
• Spacer "3"
• Needle jet "4"
•Main jet "5"
11. Install:
• Needle valve "1"
•Float "2"
• Float pin "3"
• After installing the needle valve to
the float, install them to the carbure-
tor.
• Check the float for smooth move-
ment.
12. Install: (For EUROPE)
• Pilot screw "1"
• Spring "2"
• Washer "3"
• O-ring "4"
Note the following installation
points:
a. Turn in the pilot screw until it is
lightly seated.
b. Turn out the pilot screw by the
number of turns recorded before
removing.
13. Install:
• O-ring
• Leak jet "1"
• Float chamber "2"
• Bolt (float chamber) "3"
• Cable holder (throttle stop screw
cable) "4"
• Hose holder (carburetor breather
hose) "5"
14. Install:
• Diaphragm (air cut valve) "1"
• Spring (air cut valve) "2"
• O-ring "3"
• Air cut valve cover "4"
• Holder (cylinder head breather
hose) "5"
• Screw (air cut valve cover) "6"
15. Install:
• Diaphragm (accelerator pump)
"1"
• Spring "2"
• O-ring "3"
• Accelerator pump cover "4"
• Hose holder (drain hose) "5"
• Screw (accelerator pump cover)
"6"
Install the diaphragm (accelerator
pump) with its mark "a" facing the
spring.
Pilot screw (example):
2 turns out