steering YAMAHA TTR125 2002 User Guide

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INSP
ADJ

PRE-OPERATION INSPECTION AND MAINTENANCE
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation or practice, make sure the machine is in good operating condi-
tion.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCE
Item Routine Page
FuelCheck that a fresh gasoline is filled in the fuel tank. Check the
fuel line for leakage.P.1-12
Engine oilCheck that the oil level is correct. Check the crankcase for leak-
age.P.3-7 ~ 10
Gear shifter and clutchCheck that gears can be shifted correctly in order and that the
clutch operates smoothly.P.3-4
Throttle grip/housingCheck that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary.P.3-4 ~ 5
BrakesCheck the play of front and rear brake and effect of front and
rear brake.
Check fluid level and leakage. (TT-R125LW only)P.3-15 ~ 20
Drive chainCheck chain slack and alignment. Check that the chain is lubri-
cated properly.P.3-21 ~ 22
WheelsCheck for excessive wear and tire pressure. Check for loose
spokes and have no excessive play.P.3-24 ~ 25
SteeringCheck that the handlebar can be turned smoothly and have no
excessive play.P.3-25 ~ 27
Front forks and rear shock
absorber assemblyCheck that they operate smoothly and there is no oil leakage. P.3-23 ~ 24
Cables (wires)Check that the clutch and throttle cables move smoothly. 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. P.4-2
Sprocket Check that the driven sprocket tightening nut is not loose. P.3-20
Lubrication Check for smooth operation. Lubricate if necessary. P.3-28
Bolts and nuts Check the chassis and engine for loose bolts and nuts. —
Lead connectorsCheck that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly.P.1-5

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INSP
ADJSPOKES INSPECTION AND TIGHTENING/WHEEL INSPECTION/
STEERING HEAD INSPECTION AND ADJUSTMENT
SPOKES INSPECTION AND TIGHTENING
1. Inspect:
lSpokes 1
Bend/damage ® Replace.
Loose spoke ® Retighten.
2. Tighten:
lSpokes
NOTE:
Be sure to retighten these spokes before and
after break-in. After a practice check spokes
for looseness.
T R..Front 2 Nm (0.2 m · kg, 1.4 ft · lb)
Rear 3 Nm (0.3 m · kg, 2.2 ft · lb)
EC36T000
WHEEL INSPECTION
1. Inspect:
lWheel runout
Elevate the wheel and turn it.
Abnormal runout ® Replace.
2. Inspect:
lBearing free play
Exist play ® Replace.
STEERING HEAD INSPECTION AND
ADJUSTMENT
1. Elevate the front wheel by placing a suit-
able stand under the engine.
2. Check:
lSteering shaft
Grasp the bottom of the forks and gen-
tly rock the fork assembly back and
forth.
Free play ® Adjust steering head.

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INSP
ADJ
STEERING HEAD INSPECTION AND ADJUSTMENT
3. Check:
lSteering smooth action
Turn the handlebar lock to lock.
Unsmooth action ® Adjust steering ring
nut.
4. Adjust:
lSteering ring nut
Steering ring nut adjustment steps:
lRemove the number plate and starter
knob.
lRemove the handlebar and upper bracket.
lRemove the special washer 1
lRemove the upper ring nut 2, and rubber
washer 3.
lLoosen the lower ring nut 4 using the
steering nut wrench 5.
Steering nut wrench:
YU-33975/90890-01403
lTighten the lower ring nut 6 using steer-
ing nut wrench 7 and turn the steering
right and left a few times.
Steering nut wrench:
YU-33975/90890-01403
T R..
Lower ring nut (initial tightening):
38 Nm (3.8 m • kg, 27 ft • lb)
lLoosen the lower ring nut one turn.
lRetighten the lower ring nut using the
steering nut wrench.
NOTE:
Set the torque wrench to the steering nut
wrench so that they form a right angle.
WARNING
Avoid over-tightening.

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INSP
ADJ
STEERING HEAD INSPECTION AND ADJUSTMENT
T R..
Ring nut (final tightening):
20 Nm (2.0 m • kg, 14 ft • lb)
lCheck the steering stem by turning it lock
to lock. If there is any binding, remove the
steering stem assembly and inspect the
steering bearings.
lInstall the rubber washer 8, upper ring
nut 9 and special washer 0.
NOTE:
lTighten the upper ring nut until it contacts
the rubber washer.
lInsert the special washer pawls into the
slots. If the slots are not aligned, tighten
the upper ring nut for alignment.
lInstall the upper bracket A, steering stem
nut B, cap C, handlebar D, upper han-
dlebar holder E, starter knob nut F and
number plate G.
NOTE:
lThe upper handlebar holder should be
installed with the punched mark a for-
ward.
lInsert the end of fuel breather hose H into
the hole of the starter knob stay.
CAUTION:
First tighten the bolts on the front side of
the handlebar holder, and then tighten
the bolts on the rear side.
T R..
Pinch bolt (upper bracket):
25 Nm (2.5 m • kg, 18 ft • lb)
Steering stem nut:
110 Nm (11.0 m • kg, 80 ft • lb)
Handlebar upper holder:
23 Nm (2.3 m • kg, 17 ft • lb)
Starter knob nut:
1 Nm (0.1 m • kg, 0.7 ft • lb)
Number plate:
7 Nm (0.7 m • kg, 5.1 ft • lb)

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CHASSTEERING
EC560000
STEERING
Extent of removal:1 Lower bracket removal2 Bearing removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalSTEERING REMOVAL
Hold the machine by placing the
suitable stand under the engine.
WARNING
Support the machine securely so there is nodanger of it falling over.
Front forks Refer to “FRONT FORK” section.
Handlebar Refer to “HANDLEBAR” section.
Front fender
1 Steering stem nut 1
2 Upper bracket 1
3 Special washer 1
4 Upper ring nut 1
Use special tool.
Refer to “REMOVAL POINTS”. 5 Rubber washer 1
6 Lower ring nut 1
7 Lower bracket 1
8Bearing cover
1
21

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CHASSTEERING
Extent of removal Order Part name Q’ty Remarks
9 Bearing inner race (upper) 1
10 Bearing (upper) 1
11 Bearing outer race (upper) 1
Refer to “REMOVAL POINTS”.
12 Bearing outer race (lower) 1
13Bearing (lower)
1Refer to “REMOVAL POINTS”.
2

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CHAS
EC563000
REMOVAL POINTS
EC563202
Ring nut
1. Remove:
lRing nut 1
Use the steering nut wrench 2.
WARNING
Support the steering shaft so that it may
not fall down.
Steering nut wrench:
YU-33975/90890-01403
Bearing race
1. Remove:
lBearing race 1
Remove the bearing race using long
rod 2 and the hammer.
EC563300
Bearing (lower)
1. Remove:
lBearing (lower) 1
Use the floor chisel 2.
CAUTION:
Take care not to damage the steering shaft
thread.
EC564000
INSPECTION
Steering stem
1. Inspect:
lSteering stem 1
Bend/damage ® Replace.
STEERING

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CHAS
Bearing and bearing race
1. Wash the bearings and bearing races
with a solvent.
2. Inspect:
lBearing
lBearing race
Pitting/damage ® Replace bearings
and bearing races as a set.
Install the bearing in the bearing races.
Spin the bearings by hand. If the bear-
ings hang up or are not smooth in their
operation in the bearing races, replace
bearings and bearing races as a set.
EC565000
ASSEMBLY AND INSTALLATION
Lower bracket
1. Install:
lBearing (lower) 1
NOTE:
Apply the lithium soap base grease on the dust
seal lip and bearing inner circumference.
2. Install:
lBearing outer race (lower)
lBearing outer race (upper)
3. Install:
lBearing (upper)
lBearing inner race 1
lBearing cover 2
NOTE:
Apply the lithium soap base grease on the
bearing and bearing cover lip.
STEERING

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CHAS
4. Install:
lLower bracket 1
NOTE:
Apply the lithium soap base grease on the
bearing.
5. Install:
lLower ring nut 1
lRubber washer
lUpper ring nut
lSpecial washer
Tighten the ring nut using the steering
nut wrench 2 .
NOTE:
Install the lower ring nut with its larger cham-
fered portion a facing downward.
Refer to “STEERING HEAD INSPEC-
TION AND ADJUSTMENT” section in
the CHAPTER 3.
6. 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.
T R..20 Nm (2.0 m · kg, 14 ft · lb)
7. Install:
lUpper bracket 1
lSteering stem nut 2
lStarter knob bracket 3
NOTE:
Do not tighten the steering stem nut yet.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
8. Install:
lFront forks 1
NOTE:
lTemporarily tighten the pinch bolts (lower
bracket) 2.
lDo not tighten the pinch bolts (upper bracket)
yet.
STEERING

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CHAS
9. Tighten:
lSteering stem nut 1
10. Install:
lCap 2
11. After tightening the nut, check the steer-
ing for smooth movement. If not, adjust
the steering by loosening the ring nut little
by little.
T R..110 Nm (11.0 m · kg, 80 ft · lb)
12. Adjust:
lFront fork top end a
Front fork top end (standard) a:
Zero mm (Zero in)
13. Tighten:
lPinch bolts (lower bracket) 1
lPinch bolts (upper bracket) 2
T R..60 Nm (6.0 m · kg, 43 ft · lb)
T R..25 Nm (2.5 m · kg, 18 ft · lb)
STEERING