2010 YAMAHA YZ250F Owners Manual

5-32
SWINGARM
DISASSEMBLING THE SWINGARMOrder Part name Q'ty Remarks1 Relay arm 1
2 Connecting rod 1
3 Collar 2
4 Oil seal 2
5 Thrust bearing 2
6 Bushing 2
7 Oil seal 8
8 Bearing 10 Refer to removal section.

5-33
SWINGARM
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
REMOVING THE BEARING
1. Remove:• Bearing "1"
Remove the bearing by pressing its
outer race.
CHECKING THE SWINGARM
1. Inspect:• Bearing "1"
• Bushing "2"
Free play exists/unsmooth revolu-
tion/rust →Replace bearing and
bushing as a set.
2. Inspect: • Oil seal "3"Damage →Replace.
CHECKING THE RELAY ARM
1. 5294Inspect: • Bearing "1"
•Collar "2"
Free play exists/unsmooth revolu-
tion/rust → Replace bearing and
collar as a set.
2. Inspect: • Oil seal "3"Damage →Replace. CHECKING THE CONNECTING
ROD
1. Inspect:
•Bearing "1"
• Collar "2"Free play exists/unsmooth revolu-
tion/rust → Replace bearing and
collar as a set.
2. Inspect: • Oil seal "3"
Damage →Replace.
INSTALLING THE BEARING AND
OIL SEAL
1. Install: •Bearing "1"
• Oil seal "2"To swingarm.
• Apply the molybdenum disulfide
grease on the bearing when install-
ing.
• Install the bearing by pressing it on
the side having the manufacture's
marks or numbers.
• First install the outer and then the
inner bearings to a specified depth
from inside.
2. Install: • Bearing "1"
• Washer "2"
• Oil seal "3"To relay arm.
• Apply the molybdenum disulfide grease on the bearing when install-
ing.
• Install the bearing by pressing it on the side having the manufacture's
marks or numbers.
• Apply the molybdenum disulfide grease on the washer.
3. Install:• Bearing "1"
• Oil seal "2"To connecting rod.
• Apply the molybdenum disulfide grease on the bearing when install-
ing.
• Install the bearing by pressing it on the side having the manufacture's
marks or numbers.
Installed depth of bear-
ings:
Outer "a": Zero mm
(Zero in)
Inner "b": 6.5 mm (0.26
in)
Installed depth of bear-
ings "a": Zero mm (Zero in)
Installed depth of bear-
ings "a": Zero mm (Zero in)

5-34
SWINGARM
INSTALLING THE SWINGARM
1. Install:• Bushing "1"
• Thrust bearing "2"
• Oil seal "3"
•Collar "4"To swingarm "5".
Apply the molybdenum disulfide
grease on the bushings, thrust bear-
ings, oil seal lips and contact surfaces
of the collar and thrust bearing.
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"
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)

5-35
SWINGARM
11. Tighten:• Nut (relay arm) "1"
12. Install: • Bolt (lower chain tensioner) "1"
• Washer "2"
•Collar "3"
• Lower chain tensioner "4"
• Nut (lower chain tensioner) "5"
13. Install: • Drive chain support "1"
• Drive chain support cover "2"
• Bolt {drive chain support [L = 50 mm (1.97 in)]} "3"
• Nut (drive chain support) "4"
• Bolt {drive chain support cover [L
= 10 mm (0.3 9 in)]} "5"
Nut (relay arm):
70 Nm (7.0 m•kg, 50
ft•lb)
Nut (lower chain tension-
er): 16 Nm (1.6 m•kg, 11
ft•lb)
Nut (drive chain sup-
port): 7 Nm (0.7 m•kg, 5.1
ft•lb)
Bolt (drive chain support
cover): 7 Nm (0.7 m•kg, 5.1
ft•lb)

5-36
REAR SHOCK ABSORBER
REAR SHOCK ABSORBER
REMOVING THE REAR SHOCK ABSORBEROrder Part name Q'ty Remarks Hold the machine by placing the suitable stand
under the engine. Refer to "HANDLING NOTE".
Seat Refer to "SEAT, FUEL TANK AND SIDE
COVERS" section in the CHAPTER 4.
Silencer Refer to "EXHAUST PIPE AND SILENCER"
section in the CHAPTER 4.
1 Clamp (air filter joint) 1 Only loosening.
2Rear frame 1
3 Bolt (rear shock absorber-relay arm) 1 Hold the swingarm.
4 Bolt (rear shock absorber-frame) 1
5 Rear shock absorber 1
6 Locknut 1 Only loosening.
7 Adjuster 1 Only loosening.
8 Lower spring guide 1
9 Upper spring guide 1
10 Spring (rear shock absorber) 1
11 Bearing 2 Refer to removal section.
B2
9
8
10
11
11

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 follow ing 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.

5-38
REAR SHOCK ABSORBER
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"
Install the bearing by pressing it on
the side having the manufacture's
marks or numbers.
INSTALLING THE SPRING (REAR
SHOCK ABSORBER)
1. Install:• Spring "1"
• Upper spring guide "2"
• Lower spring guide "3"
2. Tighten: •Adjuster "1"
3. Adjust: • Spring length (installed)
Refer to "ADJUSTING THE
REAR SHOCK ABSORBER
SPRING PRELOAD" section in
the CHAPTER 3.
4. Tighten: • Locknut "1"
INSTALLING THE REAR SHOCK
ABSORBER
1. Install: • Dust seal "1"
• O-ring "2"
• Collar "3"
• Apply the molybdenum disulfide grease on the dust seal lips and col-
lars.
• Apply the lithium soap base grease on the O-rings.
2. Install:
• Bushing "1"
•Collar "2"
• Dust seal "3"
• Apply the molybdenum disulfide grease on the bearing and dust seal
lips.
• Install the dust seals with their lips
facing inward.
3. Install:• Rear shock absorber
4. Install: • Bolt (rear shock absorber-frame)
"1"
• Washer "2"
• Nut (rear shock absorber-frame) "3"
Apply the molybdenum disulfide
grease on the bolt.
5. Install:
• Bolt (rear shock absorber-relay arm) "1"
• Nut (rear shock absorber-relay
arm) "2"
Apply the molybdenum disulfide
grease on the bolt.
Installed depth of the
bearing "a": 4 mm (0.16 in)
Nut (rear shock absorb-
er-frame):56 Nm (5.6 m•kg, 40
ft•lb)
Nut (rear shock absorb-
er-relay arm): 53 Nm (5.3 m•kg, 38
ft•lb)

5-39
REAR SHOCK ABSORBER
6. Install:• Rear frame "1"
• Bolt [rear frame (upper)] "2"
• Bolt [rear frame (lower)] "3"
7. Tighten: • Bolt (air filter joint) "1" Bolt [rear frame (upper)]:
32 Nm (3.2 m•kg, 23
ft•lb)
Bolt [rear frame (lower)]: 32 Nm (3.2 m•kg, 23
ft•lb)
Bolt (air filter joint): 3 Nm (0.3 m•kg, 2.2
ft•lb)