2010 YAMAHA WR 250F stop start

6-23
HANDLEBAR
HANDLEBAR
REMOVING THE HANDLEBAROrder Part name Q'ty Remarks Headlight
1 Hot starter cable 1 Disconnect at the lever side.
2 Hot starter lever holder 1
3 Clutch cable 1 Disconnect at the lever side.
4 Clutch lever holder 1 Disconnect the clutch switch lead.
5 Engine stop switch 1 Disconnect the engine stop switch lead.
6 Brake master cylinder 1 Refer to removal section.
7 Start switch 1 Disconnect the start switch lead.
8 Throttle cable cap 1
9 Throttle cable #1 (pulled) 1 Disconnect at the throttle side.
10 Throttle cable #2 (pushed) 1 Disconnect at the throttle side.
11 Right grip 1 Refer to removal section.
12 Tube guide 1
13 Left grip 1 Refer to removal section.
14 Handlebar upper holder 2
15 Handlebar 1
16 Handlebar lower holder 2

6-25
HANDLEBAR
5. Install:• Right grip "1"
•Collar "2"Apply the adhesive on the tube
guide "3".
• Before applying the adhesive, wipe
off grease or oil on the tube guide
surface "a" with a lacquer thinner.
• Install the grip to the tube guide so
that the grip match mark "b" and
tube guide slot "c" form the angle as
shown.
6. Install:• Grip cap cover "1"
• Throttle grip "2"
Apply the lithium soap base grease
on the throttle grip sliding surface.
7. Install:
• Throttle cables "1"To tube guide "2".
Apply the lithium soap base grease
on the throttle cable end and tube
guide cable winding portion.
8. Install:• Throttle cable cap "1"
• Screw (throttle cable cap) "2"
After tightening the screws, check
that the throttle grip "3" moves
smoothly. If it does not, retighten
the bolts for adjustment.
9. Install:
• Grip cap cover "1"
• Cover (throttle cable cap) "2" 10. Install:
• Start switch "1"
• Brake master cylinder "2"
• Brake master cylinder bracket "3"
• Bolt (brake master cylinder brack-et) "4"
• Clamp "5"
• The start switch and brake master
cylinder bracket should be installed
according to the dimensions
shown.
• Install the bracket so that the arrow mark "a" faces upward.
• First tighten the bolt on the upper
side of the brake master cylinder
bracket, and then tighten the bolt on
the lower side.
11. Install:• Engine stop switch "1"
• Clutch lever holder "2"
• Bolt (clutch lever holder) "3"
• Hot starter lever holder "4"
• Bolt (hot starter lever holder) "5"
• Clamp "6"
Screw (throttle cable
cap): 4 Nm (0.4 m•kg, 2.9
ft•lb)
Bolt (brake master cylin-
der bracket):
9 Nm (0.9 m•kg, 6.5
ft•lb)
Bolt (clutch lever holder): 4 Nm (0.4 m•kg, 2.9
ft•lb)
Bolt (hot starter lever
holder): 4 Nm (0.4 m•kg, 2.9
ft•lb)

6-26
HANDLEBAR
• The engine stop switch, clutch lever holder and clamp should be in-
stalled according to the dimensions
shown.
• Pass the engine stop switch lead in
the middle of the clutch lever hold-
er.
12. Install:• Clutch cable "1"
• Hot starter cable "2"
Apply the lithium soap base grease
on the clutch cable end and hot start-
er cable end.
13. Adjust:• Clutch lever free play
Refer to "ADJUSTING THE
CLUTCH CABLE FREE PLAY"
section in the CHAPTER 3.
• Hot starter lever free play Refer to "ADJUSTING THE HOT
STARTER LEVER FREE PLAY"
section in the CHAPTER 3.

7-1
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
ELECTRICAL
This section is intended for those who have basic knowledge and skill concerning the servicing of Yamaha motorcycles
(e.g., Yamaha dealers, service engineers, etc.) Those who have little knowledge and skill concerning servicing are request-
ed not to undertake inspection, adjustment, disassembly, or reassembly only by reference to this manual. It may lead to
servicing trouble and mechanical damage.
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
ELECTRICAL COMPONENTS
1. Headlight
2. Multi-function display
3. Engine stop switch
4. Clutch switch
5. Diode
6. Starter relay diode
7. Throttle position sensor
8. Starter relay
9. Fuse
10. Starting circuit cut-off relay
11. CDI unit 12. Taillight
13. Neutral switch
14. Starter motor
15. AC magneto
16. Rectifier/regulator
17. Ignition coil
18. Spark plug
19. Start switch
20. Main switch
21. Speed sensor
22. Battery

7-2
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
WIRING DIAGRAM
1. Headlight
2. Multi-function display
3. Engine stop switch
4. Clutch switch
5. Diode
6. Starter relay diode
7. Throttle position sensor
8. Starter relay
9. Fuse
10. Starting circuit cut-off relay
11. CDI unit
12. Taillight
13. Neutral switch
14. Starter motor
15. AC magneto
16. Rectifier/regulator
17. Ignition coil
18. Spark plug
19. Start switch
20. Main switch
21. Speed sensor
22. Battery
*1: For USA, CDN and EUROPE
*2: For AUS, NZ and ZACOLOR CODE
BBlack
Br Brown
Ch Chocolate
Dg Dark green
GGreen
Gy Gray
LBlue
O Orange
RRed
Sb Sky blue
WWhite
YYellow
B/L Black/Blue
B/W Black/White
L/B Blue/Black
L/R Blue/Red
L/Y Blue/Yellow
L/W Blue/White
R/B Red/Black
R/W Red/White


7

7-4
IGNITION SYSTEM
SPARK GAP TEST
1. Disconnect the ignition coil from spark plug.
2. Remove the ignition coil cap.
3. Connect the dynamic spark tester "1" (ignition ch ecker "2") as
shown.
• Ignition coil "3"
• Spark plug "4"
A. For USA and CDN
B. Except for USA and CDN
4. Kick the kickstarter crank.
5. Check the ignition spark gap.
6. Start engine, and increase spark gap until misfire occurs. (for USA
and CDN only)
CHECKING THE COUPLERS,
LEADS AND IGNITION COIL
CONNECTION
1. Check: • Couplers and leads connection
Rust/dust/looseness/short-circuit
→ Repair or replace.
• Ignition coil and spark plug as
they are fitted
Push in the ignition coil until it
closely contacts the spark plug
hole in the cylinder head cover. CHECKING THE ENGINE STOP
SWITCH
1. Inspect:
• Engine stop switch conduction
Not conductive while it is pushed →
Replace.
Conductive while it is freed →Re-
place.
Set the tester selection position to " Ω
× 1".
2. Inspect: • Rubber part "a"Tears/damage → Replace.
CHECKING THE MAIN SWITCH
1. Inspect: • Main switch conduction
Not conductive while the main switch
is moved to "ON" →Replace.
Conductive while the main switch is
moved to "OFF" →Replace.
Set the tester selection position to " Ω
×1".
2. Inspect: • Main switch indicator light
Use 12 V battery.
Indicator light does not come on →
Replace.
3. Inspect:
• Rubber part "a"Tears/damage →Replace.
CHECKING THE IGNITION COIL
1. Remove the ignition coil cap.
2. Inspect: • Primary coil resistanceOut of specification →Replace.
Minimum spark gap:
6.0 mm (0.24 in)
Tester (+) lead →Black lead "1"
Tester (-) lead →Black lead "2"
Result Conductive (while the
engine stop switch is
pushed)
Tester (+) lead →Red lead "1"
Tester (-) lead →Brown lead "2"
Result Conductive (while the
main switch is moved
to "ON")
Battery (+) lead →Red/Black lead
"1"
Battery (-) lead →Black lead "2"
Tester (+) lead →Orange lead "1"
Tester (-) lead →Black lead "2"
Primary
coil resis- tance Tester se-
lector posi- tion
0.08–0.10
Ω at 20 °C (68 °F) Ω × 1

7-16
THROTTLE POSITION SENSOR SYSTEM
HANDLING NOTE
Do not loosen the screw (throttle
position sensor) "1" except when
changing the throttle position sen-
sor due to failure because it will
cause a drop in engine perfor-
mance.
CHECKING THE COUPLERS AND
LEADS CONNECTION
1. Check: • Couplers and leads connectionRust/dust/looseness/short-circuit
→ Repair or replace.
CHECKING THE THROTTLE
POSITION SENSOR COIL
1. Inspect: • Throttle position sensor coil resis-tance
Out of specification →Replace.
2. Loosen: • Throttle stop screw "1"
Turn out the throttle stop screw until
the throttle shaft is in the full close po-
sition.
3. Inspect:• Throttle position sensor coil vari-able resistance
Check that the resistance in in-
creased as the throttle grip is
moved from the full close position
to the full open position.
Out of specification →Replace.
CHANGING AND ADJUSTING THE
THROTTLE POSI TION SENSOR
1. Remove: • Throttle position sensor coupler
• Carburetor
2. Remove: • Screw (throttle position sensor) "1"
• Throttle position sensor "2"
Loosen the screw (throttle position
sensor) using the T25 bit.
3. Replace: • Throttle position sensor 4. Install:
• Throttle position sensor "1"
• Screw (throttle position sensor) "2"
• Align the slot "a" in the throttle posi-
tion sensor with the projection "b"
on the carburetor.
• Temporarily tighten the screw
(throttle position sensor).
5. Install:•Carburetor
• Throttle position sensor coupler
6. Adjust: • Engine idling speed
Refer to "ADJUSTING THE EN-
GINE IDLING SPEED" section in
the CHAPTER 3.
7. Insert the thin electric conductors "2" (lead) into the throttle position
sensor coupler "1", as shown, and
connect the tester to them.
• Do not insert the electric conduc-
tors more than required because
it may reduce the waterproof
function of the coupler.
• Make sure that a short-circuit does not develop between the
terminals because it may cause
damage to electrical compo-
nents.
8. Start the engine.
Tester (+) lead
→Blue lead "1"
Tester (-) lead →Black lead "2"
Throttle po- sition sen-
sor coil
resistance Tester se-
lector posi- tion
4–6 k Ω at
20°C (68 °F) k
Ω×1
Tester (+) lead →Yellow lead "1"
Tester (-) lead →Black lead "2"
Throttle posi-
tion sensor coil
variable resis- tance Tester
selec-
tor po- sition
Full
closed Full
opene
d
kΩ×1
Zero –3
k Ωat
20°C
(68 °F) 4–6
k Ωat
20 °C
(68 °F)
Tester (+) lead →Yellow lead "3"
Tester (-) lead →Black lead "4"

7-17
THROTTLE POSITION SENSOR SYSTEM
9. Adjust:• Throttle position sensor output voltage
Adjustment steps:
a. Adjust the installation angle of the
throttle position sensor "1" to ob-
tain the specified output voltage.
Measure the output voltage accurate-
ly with a digital electronic voltmeter
that gives an easy reading of a small
voltage.
10. Put the aligning marks "a" on the throttle position sensor and car-
buretor.
11. Stop the engine.
12. Remove the carburetor.
13. Tighten: • Screw (throttle position sensor) "1"
Tighten the screw (throttle position
sensor) using the T25 bit.
14. Install the carburetor. CHECKING THE THROTTLE
POSITION SENSOR INPUT
VOLTAGE
1. Disconnect the throttle position
sensor coupler.
2. Start the engine.
3. Inspect:
• Throttle position sensor input volt-age
Out of specification →Replace the
CDI unit.
Throttle po- sition sen-sor output
voltage Tester se-
lector posi- tion
0.58–0.78 V DCV
Tester (+) lead →Blue lead "1"
Tester (-) lead →Black/Blue lead
"2"
Throttle po-sition sen- sor input voltage Tester se-
lector posi-
tion
4–6 V DCV-20