2012 YAMAHA YZ125LC Owners Manual

5-37
SWINGARM
10. Tighten:
• Nut (connecting rod) "1"
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 (connecting rod):
80 Nm (8.0 m•kg, 58
ft•lb)
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)

5-38
REAR SHOCK ABSORBER
REAR SHOCK ABSORBER
REMOVING THE REAR SHOCK ABSORBER
Order 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 Spring seat 2
9 Lower spring guide 1
10 Upper spring guide 1
11 Spring (rear shock absorber) 1
53 Nm (5.3 m kg, 38 ft lb)
56 Nm (5.6 m kg, 40 ft lb)
2 Nm (0.2 m kg, 1.4 ft lb)
32 Nm (3.2 m kg, 23 ft lb)
29 Nm (2.9 m kg, 21 ft lb)

5-39
REAR SHOCK ABSORBER
12 Bearing 2 Refer to removal section. Order Part name Q'ty Remarks
53 Nm (5.3 m kg, 38 ft lb)
56 Nm (5.6 m kg, 40 ft lb)
2 Nm (0.2 m kg, 1.4 ft lb)
32 Nm (3.2 m kg, 23 ft lb)
29 Nm (2.9 m kg, 21 ft lb)

5-40
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.
• Spring seat "5"
Cracks/damage →Replace.
• Bearing "6"
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.

5-41
REAR SHOCK ABSORBER
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. 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 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)

5-42
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)]:
29 Nm (2.9 m•kg, 21
ft•lb)
Bolt (air filter joint):
2 Nm (0.2 m•kg, 1.4
ft•lb)

6-1
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.
6

6-2
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
ELECTRICAL COMPONENTS AND WIRING DIAGRAM
ELECTRICAL COMPONENTS
1. Engine stop switch
2. CDI unit3. Ignition coil
4. CDI magneto5. Spark plug
WIRING DIAGRAM
1. Engine stop switch
2. CDI unit
3. Ignition coil
4. CDI magneto
5. Spark plugCOLOR CODE
BBlack
O Orange
YYellow
B/R Black/Red
B/W Black/White
G/L Green/Blue
G/W Green/White
W/L White/Blue
W/R White/Red