2009 YAMAHA YZ250F check oil

5-34
SWINGARM
2. Install:
•Collar "1"
• Washer "2"
To relay arm "3".
Apply the molybdenum disulfide
grease on the collars and oil seal lips.
3. Install:
•Collar "1"
To connecting rod "2".
Apply the molybdenum disulfide
grease on the collar and oil seal lips.
4. Install:
• Connecting rod "1"
• Bolt (connecting rod) "2"
• Washer "3"
• Nut (connecting rod) "4"
To relay arm "5".
Apply the molybdenum disulfide
grease on the bolt.
5. Install:
• Relay arm "1"
• Bolt (relay arm) "2"
•Washer "3"
• Nut (relay arm) "4"
To swingarm.
• Apply the molybdenum disulfide
grease on the bolt circumference
and threaded portion.
• Do not tighten the nut yet.
6. Install:
• Swingarm "1"
• Pivot shaft "2"
• Apply the molybdenum disulfide
grease on the pivot shaft.
• Insert the pivot shaft from right side.
7. Check:
• Swingarm side play "a"
Free play exists→Replace thrust
bearing.
• Swingarm up and down move-
ment "b"
Unsmooth movement/binding/
rough spots →Grease or replace
bearings, bushings and collars.
8. Install:
• Bolt (connecting rod) "1"
•Washer "2"
• Nut (connecting rod) "3"
• Apply the molybdenum disulfide
grease on the bolt.
• Do not tighten the nut yet.
9. Install:
• Bolt (rear shock absorber-relay
arm) "1"
• Nut (rear shock absorber-relay
arm) "2"
Apply the molybdenum disulfide
grease on the bolt.
10. Tighten:
• Nut (connecting rod) "1"
11. Tighten:
• Nut (relay arm) "1" Nut (connecting rod):
80 Nm (8.0 m•kg, 58
ft•lb)
Pivot shaft:
85 Nm (8.5 m•kg, 61
ft•lb)
Nut (rear shock absorb-
er-relay arm):
53 Nm (5.3 m•kg, 38
ft•lb)
Nut (connecting rod):
80 Nm (8.0 m•kg, 58
ft•lb)
Nut (relay arm):
70 Nm (7.0 m•kg, 50
ft•lb)

5-37
REAR SHOCK ABSORBER
HANDLING NOTE
• Support the machine securely so
there is no danger of it falling
over.
• This rear shock absorber is pro-
vided with a separate type tank
filled with high-pressure nitro-
gen gas. To prevent the danger
of explosion, read and under-
stand the following information
before handling the shock ab-
sorber. The manufacturer can
not be held responsible for prop-
erty damage or personal injury
that may result from improper
handling.
• Never tamper or attempt to dis-
assemble the cylinder or the
tank.
• Never throw the rear shock ab-
sorber into an open flame or
other high heat. The rear shock
absorber may explode as a re-
sult of nitrogen gas expansion
and/ or damage to the hose.
• Be careful not to damage any
part of the gas tank. A damaged
gas tank will impair the damp-
ing performance or cause a
malfunction.
• Take care not to scratch the
contact surface of the piston
rod with the cylinder; or oil
could leak out.
• Never attempt to remove the
plug at the bottom of the nitro-
gen gas tank. It is very danger-
ous to remove the plug.
• When scrapping the rear shock
absorber, follow the instruc-
tions on disposal.
NOTES ON DISPOSAL (YAMAHA
DEALERS ONLY)
Before disposing the rear shock ab-
sorber, be sure to extract the nitrogen
gas from valve "1". Wear eye protec-
tion to prevent eye damage from es-
caping gas and/or metal chips.
To dispose of a damaged or worn-
out rear shock absorber, take the
unit to your Yamaha dealer for this
disposal procedure.
REMOVING THE BEARING
1. Remove:
• Stopper ring (upper bearing) "1"
Press in the bearing while pressing its
outer race and remove the stopper
ring.
2. Remove:
• Upper bearing "1"
Remove the bearing by pressing its
outer race.
3. Remove:
• Lower bearing "1"
Remove the bearing by pressing its
outer race.
CHECKING THE REAR SHOCK
ABSORBER
1. Inspect:
• Damper rod "1"
Bends/damage→Replace rear
shock absorber assembly.
• Shock absorber "2"
Oil leaks→Replace rear shock
absorber assembly.
Gas leaks→Replace rear shock
absorber assembly.
• Spring "3"
Damage→Replace spring.
Fatigue→Replace spring.
Move spring up and down.
• Spring guide "4"
Wear/damage→Replace spring
guide.• Bearing "5"
Free play exists/unsmooth revolu-
tion/rust →Replace.
INSTALLING THE BEARING
1. Install:
• Upper bearing "1"
Install the bearing parallel until the
stopper ring groove appears by
pressing its outer race.
Do not apply the grease on the
bearing outer race because it will
wear the rear shock absorber sur-
face on which the bearing is press
fitted.
2. Install:
• Stopper ring (upper bearing) "1"
After installing the stopper ring, push
back the bearing until it contacts the
stopper ring.
3. Install:
• Lower bearing "1"

6-3
IGNITION SYSTEM
IGNITION SYSTEM
INSPECTION STEPS
Use the following steps for checking the possibility of the malfunctioning engine being attributable to ignition system failure
and for checking the spark plug which will not spark.
*marked: Only when the ignition checker is used.
• Remove the following parts before inspection.
1. Seat
2. Fuel tank
• Use the following special tools in this inspection.
Spark gap test Spark→*Clean or replace spark plug.
No spark↓
Check entire ignition system for connection.
(couplers, leads and ignition coil)No good→
Repair or replace.
OK↓
Check engine stop switch. No good→Replace.
OK↓
Check ignition coil. (primary coil and secondary
coil)No good→
Replace.
OK↓
Check CDI magneto. (pickup coil and charging
coil)No good→
Replace.
OK↓
Check neutral switch. No good→Repair or replace.
OK↓
Replace CDI unit.
Dynamic spark tester:
YM-34487
Ignition checker:
90890-06754
Pocket tester:
YU-3112-C/90890-03112

6-4
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 checker "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 conductionNot conductive while it is pushed→
Replace.
Conductive while it is freed→Re-
place.
Set the tester selection position to "Ω
× 1".
CHECKING THE IGNITION COIL
1. Remove the ignition coil cap.
2. Inspect:
• Primary coil resistance
Out of specification→Replace.
3. Inspect:
• Secondary coil resistance
Out of specification→Replace.4. Inspect:
• Sealed portion of ignition coil "a"
• Spark plug terminal pin "b"
• Threaded portion of spark plug "c"
Wear →Replace.
CHECKING THE CDI MAGNETO
1. Inspect:
• Pickup coil resistance
Out of specification→Replace.
2. Inspect:
• Charging coil 1 resistance
Out of specification→Replace. Minimum spark gap:
6.0 mm (0.24 in)
Tester (+) lead→Black/White lead
"1"
Tester (-) lead→Black lead "2"
Result
Conductive (while the
engine stop switch is
pushed)
Tester (+) lead→Orange lead "1"
Tester (-) lead→Black lead "2"
Primary
coil resis-
tanceTester se-
lector posi-
tion
0.08–0.10
Ω at 20 °C
(68 °F) Ω × 1
Tester (+) lead→Orange lead "1"
Tester (-) lead→Spark plug termi-
nal "2"
Secondary
coil resis-
tanceTester se-
lector posi-
tion
4.6–6.8
kΩat 20 °C
(68 °F) kΩ × 1
Tester (+) lead→Red lead "1"
Tester (-) lead→White lead "2"
Pickup coil
resistanceTester se-
lector posi-
tion
248-372 Ω
at 20 °C (68
°F)Ω ×100
Tester (+) lead→Brown lead "1"
Tester (-) lead→Green lead "2"
Charging
coil 1 resis-
tanceTester se-
lector posi-
tion
720-1,080
Ω at 20 °C
(68 °F)Ω ×100

6-5
IGNITION SYSTEM
3. Inspect:
• Charging coil 2 resistance
Out of specification→Replace.
CHECKING THE NEUTRAL
SWITCH
1. Inspect:
• Neutral switch conduction
Not conductive while it is in neutral→
Replace.
Conductive while it is engaged→Re-
place.
Set the tester selection position to "Ω
× 1".
CHECKING THE CDI UNIT
Check all electrical components. If no
fault is found, replace the CDI unit.
Then check the electrical compo-
nents again.Tester (+) lead→Pink lead "1"
Tester (-) lead→Black lead "2"
Charging
coil 2 resis-
tanceTester se-
lector posi-
tion
44-66 Ω at
20 °C (68
°F)Ω ×10
Tester (+) lead→Sky blue lead "1"
Tester (-) lead→Ground "2"
Result
Conductive (while gear
is in neutral)

6-6
THROTTLE POSITION SENSOR SYSTEM
THROTTLE POSITION SENSOR SYSTEM
INSPECTION STEPS
If the throttle position sensor will not operate, use the following inspection steps.
*marked: Refer to "IGNITION SYSTEM" section.
Use the following special tools in this inspection.
Check entire ignition system for connection. No good→Repair or replace.
OK↓
Check throttle position sensor. (Throttle position
sensor coil)No good→
Replace.
OK↓
*Check CDI magneto. (Charging coil) No good→Replace.
OK↓
Check CDI unit. (Throttle position sensor input
voltage)No good→
Replace.
Pocket tester:
YU-3112-C/90890-03112

6-7
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 connection
Rust/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 POSITION 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.
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. Tester (+) lead→Blue lead "1"
Tester (-) lead→Black lead "2"
Throttle po-
sition sen-
sor coil
resistanceTester se-
lector posi-
tion
4–6 kΩ at
20°C (68 °F) kΩ×1
Tester (+) lead→Yellow lead "1"
Tester (-) lead→Black lead "2"
Throttle position
sensor coil vari-
able resistanceTester
selec-
tor po-
sition
Full
closedFull
opened
kΩ×1 Zero –3
kΩat
20°C
(68 °F)4–6
kΩat
20 °C
(68 °F)
Tester (+) lead→Yellow lead "3"
Tester (-) lead→Black lead "4"

7-10
CHASSIS
SUSPENSION SETTING (FRONT FORK)
• If any of the following symptoms is experienced with the standard position as the base, make resetting 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
range○○○Compression damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Oil amount Decrease oil amount by about 5–10 cm
3 (0.2–0.4
Imp oz, 0.2–0.3 US oz).
Spring Replace with soft spring.
Unsmooth move-
ment over entire
range○○○○Outer tube Check for any bends, dents, and other noticeable
scars, etc. If any, replace affected parts.
Inner tube
Slide metal Replace with a new one for extended use.
Piston metal Replace with a new one for extended use.
Under bracket tighten-
ing torqueRetighten to specified torque.
Poor initial move-
ment○Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Oil seal Apply grease in oil seal wall.
Soft over entire
range, bottoming
out○○Compression damping Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Oil amount Increase oil amount by about 5–10 cm
3 (0.2–0.4
Imp oz, 0.2–0.3 US oz).
Spring Replace with stiff spring.
Stiff toward stroke
end○Oil amountDecrease oil amount by about 5 cm
3 (0.2 Imp
oz,0.2 US oz).
Soft toward stroke
end, bottoming out○Oil amountIncrease oil amount by about 5 cm
3 (0.2 Imp
oz,0.2 US oz).
Stiff initial move-
ment○○○○Compression dampingTurn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Low front, tending to
lower front posture○○Compression damping Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Rebound damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Balance with rear end Set sunken length for 95–100 mm (3.7–3.9 in)
when one passenger is astride seat (lower rear
posture).
Oil amount Increase oil amount by about 5 cm
3 (0.2 Imp oz,
0.2 US oz).
"Obtrusive" front,
tending to upper
front posture○○Compression damping Turn adjuster counterclockwise (about 2 clicks) to
decrease damping.
Balance with rear end Set sunken length for 90–95 mm (3.5–3.7 in)
when one passenger is astride seat (upper rear
posture).
Spring Replace with soft spring.
Oil amount Decrease oil amount by about 5–10 cm
3 (0.2–0.4
Imp oz, 0.2–0.3 US oz).