2005 YAMAHA YZ125LC steering

3-4
PRE-OPERATION INSPECTION AND MAINTENANCE
INSP
ADJ
EC320000
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating
condition.
Before using this machine, check the following points.
EC321000
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
Coolant Check that coolant is filled up to the radiator filler cap.
Check the cooling system for leakage.P3-5~9
Fuel Check that a fresh mixture of oil and gasoline is filled in
the fuel tank. Check the fuel line for leakage.P1-12
Transmission oil Check that the oil level is correct. Check the crankcase
for leakage.P3-12~14
Gear shifter and clutch Check that gears can be shifted correctly in order and
that the clutch operates smoothly.P3-9
Throttle grip/Housing Check that the throttle grip operation and free play
are correctly adjusted. Lubricate the throttle grip and P3-10~11
housing, if necessary.
Brakes Check the play of front brake and effect of front and
rear brake.P3-17~23
Chain Check chain slack and alignment. Check that the chain
is lubricated properly.P3-24~26
Wheels Check for excessive wear and tire pressure. Check for
loose spokes and have no excessive play.P3-34~35
Steering Check that the handlebar can be turned smoothly and
have no excessive play.P3-35~36
Front forks and Check that they operate smoothly and there is no oil
rear shock absorber leakage.P3-26~33
Cables (wires) Check that the clutch and throttle cables move smooth-
ly. Check that they are not caught when the handlebars —
are turned or when the front forks travel up and down.
Muffler Check that the muffler is tightly mounted and has no
cracks.P3-15~16
Sprocket Check that the driven sprocket tightening bolt is
not loose.P3-24
Lubrication Check for smooth operation. Lubricate if necessary. P3-37
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P1-16
Lead connectors Check that the CDI magneto, CDI unit, and ignition coil
are connected tightly.P1-6
Settings Is the machine set suitably for the condition of the
racing course and weather or by taking into account the
P7-1~23
results of test runs before racing? Are inspection and
maintenance completely done?
1C3-9-30-3A 17/5/04 8:42 PM Page 14

3-35
STEERING HEAD INSPECTION AND ADJUSTMENT
INSP
ADJ
2. Inspect:
9Bearing free play
Exist play Replace.
EC36U070
STEERING HEAD INSPECTION AND
ADJUSTMENT
1. Elevate the front wheel by placing a suitable
stand under the engine.
2. Check:
9Steering shaft
Grasp the bottom of the forks and gently
rock the fork assembly back and forth.
Free play Adjust steering head.
3. Check:
9Steering smooth action
Turn the handlebar lock to lock.
Unsmooth action Adjust steering ring
nut.
4. Adjust:
9Steering ring nut
Steering ring nut adjustment steps:
9Remove the number plate.
9Remove the handlebar and handle crown.
9Loosen the ring nut 1using the ring nut
wrench 2.
9Tighten the ring nut 3using ring nut wrench
4.
NOTE:
9Apply the lithium soap base grease on the
thread of the steering shaft.
9Set the torque wrench to the ring nut wrench
so that they form a right angle.
Ring nut wrench:
YU-33975/90890-01403
1C3-9-30-3B 17/5/04 1:21 PM Page 34

3-36
STEERING HEAD INSPECTION AND ADJUSTMENT
INSP
ADJ
9Loosen the ring nut one turn.
9Retighten the ring nut using the ring nut
wrench.
w
Avoid over-tightening.
9Check the steering shaft by turning it lock to
lock. If there is any binding, remove the
steering shaft assembly and inspect the
steering bearings.
9Install the plain washer 5, handle crown 6,
plain washer 7, steering shaft nut 8, steer-
ing shaft cap 9, handlebar 0, handlebar
holder q and number plate w.
NOTE:
9The upper handlebar holder should be
installed with the punched mark aforward.
9Install the handlebar so that the marks b
are in place on both sides.
9Insert the end of the fuel breather hose e
into the hole in the steering shaft cap.
cC
First tighten the bolts on the front side of
the handlebar holder, and then tighten the
bolts on the rear side.
Ring nut wrench:
YU-33975/90890-01403
Ring nut (initial tightening):
38 Nm (3.8 m•kg, 27ft•lb)
Steering shaft nut:
145 Nm (14.5 m•kg, 105 t•lb)
Handlebar upper holder:
28 Nm (2.8 m•kg, 20 ft•lb)
Pinch bolt (handle crown):
23 Nm (2.3 m•kg, 17 ft•lb)
Number plate:
7 Nm (0.7 m•kg, 5.1 ft•lb)
Ring nut (final tightening):
7 Nm (0.7 m•kg, 5.1 ft•lb)
1C3-9-30-3B 17/5/04 1:21 PM Page 36

5-47
CHASHANDLEBAR
14. Clamp the clamp portion aof the number
plate to the handlebar.
15. Insert the end of the fuel breather hose 1
into the hole in the steering shaft cap 2.
12. Install:
9Clutch cable 1
NOTE:
Apply the lithium soap base grease on the clutch
cable end.
13. Adjust:
9Clutch lever free play
Refer to “CLUTCH ADJUSTMENT” section in
the CHAPTER 3.
1C3-9-30-5C 25/5/04 7:29 PM Page 14

5-48
CHASSTEERING
Extent of removal Order Part name Q’ty Remarks
STEERING REMOVAL
Preparation for
Hold the machine by placing the
removalsuitable stand under the engine.
Number plate
Handlebar Refer to “HANDLEBAR” section.
Front fender
1 Steering shaft cap 1
2 Steering shaft nut 1
3 Front fork 2 Refer to “FRONT FORK” section.
4 Handle crown 1
5 Ring nut 1 Use special tool.
Refer to “REMOVAL POINTS”.
6 Under bracket 1
7 Bearing race cover 1
8 Bearing (upper) 1
9 Bearing (lower) 1 Refer to “REMOVAL POINTS”.
10 Bearing race 2 Refer to “REMOVAL POINTS”. Extent of removal:1Under bracket removal 2Bearing removal
2
1
w
Support the machine securely so there is no dan-
ger of it falling over.
EC560000
STEERING
145 Nm (14.5 m•kg, 105 ft•lb)
23 Nm (2.3 m•kg, 17 ft•lb)
9Tighten ring nut.
38 Nm (3.8 m•kg, 27 ft•lb)
9Loosen it one turn.
9Retighten it.
7 Nm (0.7 m•kg, 5.1 ft•lb)
TIGHTENING STEPS:
20 Nm (2.0 m•kg, 14 ft•lb)
4Nm (0.4 m•kg, 2.9 ft•lb)
1C3-9-30-5C 25/5/04 7:29 PM Page 16

5-49
CHASSTEERING
EC563000
REMOVAL POINTS
EC563202
Ring nut
1. Remove:
9Ring nut 1
Use the ring nut wrench 2.
w
Support the steering shaft so that it may
not fall down.
EC563300
Bearing (lower)
1. Remove:
9Bearing (lower) 1
Use the floor chisel 2.
cC
Take care not to damage the steering shaft
thread.
EC563400
Bearing race
1. Remove:
9Bearing race 1
Remove the bearing race using long rod 2
and the hammer.
EC564000
INSPECTION
EC564200
Steering shaft
1. Inspect:
9Steering shaft 1
Bend/Damage Replace.
Ring nut wrench:
YU-33975/90890-01403
1C3-9-30-5C 25/5/04 7:29 PM Page 18

5-50
CHASSTEERING
EC564101
Bearing and bearing race
1. Wash the bearings and bearing races with a
solvent.
2. Inspect:
9Bearing 1
9Bearing race
Pitting/Damage Replace bearings and
bearing races as a set.
Install the bearing in the bearingraces. Spin
the bearings by hand. If the bearings hang up
or are not smooth in their operation in the
bearingraces, replace bearings and bearing
races as a set.
EC565000
ASSEMBLY AND INSTALLATION
EC5651A0
Under bracket
1. Install:
9Bearing (lower) 1
NOTE:
Apply the lithium soap base grease on the dust
seal lip and bearing inner circumference.
2. Install:
9Bearing race
9Bearing (upper) 1
9Bearing race cover 2
NOTE:
Apply the lithium soap base grease on the bear-
ing and bearing race cover lip.
3. Install:
9Under bracket 1
NOTE:
Apply the lithium soap base grease on the bear-
ing, the portion aand thread of the steering
shaft.
1 a
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5-51
CHASSTEERING
4. Install:
9Ring nut 1
Tighten the ring nut using the ring nut
wrench 2.
Refer to “STEERING HEAD INSPECTION
AND ADJUSTMENT” section in the CHAP-
TER 3.
5. Check the steering shaft by turning it lock to
lock. If there is any binding, remove the
steering shaft assembly and inspect the
steering bearings.
6. Install:
9Plain washer 1
7. Install:
9Front fork 1
9Handle crown 2
NOTE:
9Temporarily tighten the pinch bolts (under
bracket).
9Do not tighten the pinch bolts (handle crown)
yet.
8. Install:
9Plain washer 1
9Steering shaft nut 2
7 Nm (0.7 m•kg, 5.1 ft•lb)
145 Nm (14.5 m•kg, 105 ft•lb)
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