relay YAMAHA YZ250F 2008 Owners Manual

2-13
TIGHTENING TORQUES
△Rear brake disc coverM6 × 1.0 2 10 1.0 7.2
△Rear brake caliper protector M6 × 1.0 2 7 0.7 5.1
Drive chain puller adjust bolt and locknut M8 × 1.25 2 19 1.9 12
Engine mounting:
△Engine and engine bracket (front) M10 × 1.25 1 53 5.3 38
△Engine and frame (lower) M10 × 1.25 1 53 5.3 38
△Upper engine bracket and frame M8 × 1.25 4 34 3.4 25
△Lower engine bracket and frameM8 × 1.25 4 38 3.8 27
△Engine and engine bracket (upper)M10 × 1.25 1 55 5.5 40
Lower engine guard M6 × 1.0 3 10 1.0 7.2
△Right engine guardM6 × 1.0 1 10 1.0 7.2
CDI unit bracket M6 × 1.0 2 7 0.7 5.1
Cable guide and CDI unit bracket M5 × 0.8 2 4 0.4 2.9
Cable guide and frame M5 × 0.8 1 5 0.5 3.6
△Pivot shaft and nutM16 × 1.5 1 85 8.5 61
△Relay arm and swingarmM14 × 1.5 1 70 7.0 50
△Relay arm and connecting rod M14 × 1.5 1 80 8.0 58
△Connecting rod and frame M14 × 1.5 1 80 8.0 58
△Rear shock absorber and frameM10 × 1.25 1 56 5.6 40
△Rear shock absorber and relay armM10 × 1.25 1 53 5.3 38
△Rear frame (upper) M8 × 1.25 1 38 3.8 27
△Rear frame (lower) M8 × 1.25 2 32 3.2 23
△Swingarm and brake hose holder M5 × 0.8 4 2 0.2 1.4
Swingarm and patch M4 × 0.7 4 2 0.2 1.4
Upper drive chain tensioner M8 × 1.25 1 16 1.6 11
Lower drive chain tensioner M8 × 1.25 1 16 1.6 11
Drive chain support M6 × 1.0 3 7 0.7 5.1
△Seal guard and swingarmM5 × 0.8 4 6 0.6 4.3
△Fuel tank mounting boss and frameM10 × 1.25 1 20 2.0 14
△Fuel tank M6 × 1.0 2 9 0.9 6.5
△Fuel cockM6 × 1.0 2 4 0.4 2.9
Seat set bracket and fuel tank M6 × 1.0 1 7 0.7 5.1
Fuel tank bracket and fuel tank M6 × 1.0 4 7 0.7 5.1
△Air scoop and fuel tankM6 × 1.0 6 7 0.7 5.1
△Air scoop and radiator guard (lower) M6 × 1.0 2 7 0.7 5.1
△Front fenderM6 × 1.0 4 7 0.7 5.1
△Rear fender (front) M6 × 1.0 2 7 0.7 5.1
△Rear fender (rear) M6 × 1.0 2 16 1.6 11
△Side coverM6 × 1.0 2 7 0.7 5.1
Seat M8 × 1.25 2 23 2.3 17
△Number plate M6 × 1.0 1 7 0.7 5.1
Part to be tightened
Thread size Q'tyTightening torque
Nm m•kg ft•lb

3-3
MAINTENANCE INTERVALS
OIL STRAINERClean
●
FRAMEClean and inspect
●●
FUEL TANK, COCKClean and inspect
●●
BRAKESAdjust lever position and pedal
height
●●
Lubricate pivot point●●
Check brake disc surface●●
Check fluid level and leakage●●
Retighten brake disc bolts, cali-
per bolts, master cylinder bolts
and union bolts●●
Replace pads●
Replace brake fluid●Every one year
FRONT FORKS Inspect and adjust
●●
Replace oil●●Suspension oil "S1"
Replace oil seal
●
FRONT FORK OIL SEAL AND
DUST SEAL Clean and lube
●●Lithium base grease
PROTECTOR GUIDE Replace
●
REAR SHOCK ABSORBERInspect and adjust
●●
Lube●
(After rain
ride)
●Molybdenum disulfide grease
Replace spring seat
●Every one year
Retighten
●●
DRIVE CHAIN GUIDE AND
ROLLERS Inspect
●●
SWINGARMInspect, lube and retighten
●●Molybdenum disulfide grease
RELAY ARM, CONNECTING
ROD Inspect, lube and retighten
●●Molybdenum disulfide grease
STEERING HEAD Inspect free play and retighten
●●
Clean and lube●Lithium base grease
Replace bearing
●
Item After
break-
in Every
race
Every third
(or 500 km) Every
fifth (or 1,000 km)
As re-
quired Remarks

5-32
SWINGARM
SWINGARM
REMOVING THE SWINGARMOrder Part name Q'ty Remarks Hold the machine by placing the suitable stand
under the engine. Refer to "HANDLING NOTE".
Brake hose holder Refer to "FRONT BRAKE AND REAR
BRAKE" section.
Rear brake caliper Refer to "FRONT BRAKE AND REAR
BRAKE" section.
Bolt (brake pedal) Shift the brake pedal backward.
Drive chain
1 Drive chain support 1
2 Lower chain tensioner 1
3 Bolt (rear shock absorber-relay arm) 1 Hold the swingarm.
4 Bolt (connecting rod) 1
5Pivot shaft 1
6 Swingarm 1

5-33
SWINGARM
DISASSEMBLING THE SWINGARMOrder Part name Q'ty Remarks1 Cap 2 Refer to removal section.
2 Relay arm 1
3 Connecting rod 1
4Collar 2
5 Oil seal 2
6 Thrust bearing 2
7 Bushing 2
8 Oil seal 8
9 Bearing 10 Refer to removal section.

5-34
SWINGARM
HANDLING NOTE
Support the machine securely so
there is no danger of it falling over.
REMOVING THE CAP
1. Remove:• Left cap "1"
Remove with a slotted-head screw-
driver inserted under the mark "a" on
the left cap.
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. 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.
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)

5-35
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)

5-36
SWINGARM
11. Tighten:• Nut (relay arm) "1"
12. Install: • Cap "1"
Install the right cap with its mark "a"
facing forward.
13. Install:• Bolt (lower chain tensioner) "1"
• Washer "2"
•Collar "3"
• Lower chain tensioner "4"
• Nut (lower chain tensioner) "5"
14. 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 (0.39 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)

5-37
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.
2 Rear 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 Spring seat 2
9 Lower spring guide 1
10 Upper spring guide 1
11 Spring (rear shock absorber) 1

5-40
REAR SHOCK ABSORBER
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. Install: • Spring seat "1"
Install the spring seat with the projec-
tion "a" brought into contact with the
spring end, as shown.
3. Tighten:•Adjuster "1" 4. Adjust:
• Spring length (installed)Refer to "ADJUSTING THE
REAR SHOCK ABSORBER
SPRING PRELOAD" section in
the CHAPTER 3.
5. 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 outward.
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.
6. Install:• Rear frame "1"
• Bolt [rear frame (upper)] "2"
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)
Bolt [rear frame (upper)]: 38 Nm (3.8 m•kg, 27
ft•lb)