engine YAMAHA TTR125 2002 Manual PDF

4 - 63
ENGENGINE REMOVAL
REMOVAL POINTS
Drive sprocket
1. Remove:
lBolt (drive sprocket)
lDrive sprocket holder 1
lDrive sprocket 2
lDrive chain 3
NOTE:
Remove the drive sprocket together with the
drive chain.
Engine removal
1. Remove:
lEngine 1
From left side.
NOTE:
Make sure that the couplers, hoses and cables
are disconnected.
ASSEMBLY AND INSTALLATION
Engine installation
1. Install:
lEngine 1
Install the engine from left side.
lEngine mounting bolt (rear) 2
lEngine bracket (front) 3
lBolt (engine bracket) 4
lEngine mounting bolt (lower) 5
lEngine mounting bolt (front) 6
lEngine bracket (upper) 7
lEngine mounting bolt (upper) 8
lBolt (engine bracket) 9
T R..40 Nm (4.0 m · kg, 29 ft · lb)
T R..40 Nm (4.0 m · kg, 29 ft · lb)
T R..40 Nm (4.0 m · kg, 29 ft · lb)
T R..40 Nm (4.0 m · kg, 29 ft · lb)
T R..40 Nm (4.0 m · kg, 29 ft · lb)
T R..40 Nm (4.0 m · kg, 29 ft · lb)

4 - 64
ENGENGINE REMOVAL
NOTE:
lApply the lithium soap base grease on the
thread of the engine mounting bolts (rear) 2.
lTighten the engine mounting bolt (upper) 8,
and then tighten the bolts (engine bracket)
9.
Shift pedal link
1. Install:
lShift pedal link 1
lBolt (shift pedal link) 2
NOTE:
Adjust the center a of the front end of the shift
pedal to match the highest point of the foot-
rest.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
Drive sprocket
1. Install:
lDrive sprocket 1
lDrive chain 2
NOTE:
Install the drive sprocket together with the
drive chain.
2. Install:
lDrive sprocket holder 1
lBolt (drive sprocket)
T R..6 Nm (0.6 m · kg, 4.3 ft · lb)
3. Install:
lDrive sprocket cover 1
lBolt (drive sprocket cover) 2
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)

4 - 65
ENGCRANKCASE, CRANKSHAFT AND BALANCER
CRANKCASE, CRANKSHAFT AND BALANCER
Extent of removal:1 Crankcase separation2 Balancer removal
3 Crankshaft removal
Extent of removal Order Part name Q’ty Remarks
CRANKCASE, CRANKSHAFT
AND BALANCER REMOVAL
Preparation for removal Engine Refer to “ENGINE REMOVAL” section.
Piston Refer to “CYLINDER AND PISTON” sec-
tion.
Primary drive gear Refer to “CLUTCH AND PRIMARY
DRIVEN GEAR” section.
Kick axle assembly
Refer to “KICK AXLE AND SHIFT
SHAFT” section.
Segment
Rotor and stator Refer to “CDI MAGNETO” section.

4 - 67
ENGCRANKCASE, CRANKSHAFT AND BALANCER
REMOVAL POINTS
Crankcase
1. Remove:
lBolt (crankcase)
lLead guide 1
lClutch cable holder 2
NOTE:
Loosen each bolt 1/4 of a turn at a time and
after all the bolts are loosened, remove them.
2. Remove:
lRight crankcase 1
Use the crankcase separating tool 2.
NOTE:
lFully tighten the tool holding bolts, but make
sure the tool body is parallel with the case. If
necessary, one screw may be backed out
slightly to level tool body.
lAs pressure is applied, alternately tap on the
front engine mounting boss and transmission
shafts.
CAUTION:
Use soft hammer to tap on the case half.
Tap only on reinforced portions of case. Do
not tap on gasket mating surface. Work
slowly and carefully. Make sure the case
halves separate evenly. If one end “hangs
up”, take pressure off the push screw, re-
align, and start over. If the cases do not
separate, check for a remaining case screw
or fitting. Do not force.
Crankcase separating tool:
YU-1135-A/90890-01135

4 - 69
ENGCRANKCASE, CRANKSHAFT AND BALANCER
Crankcase
1. Inspect:
lContacting surface a
Scratches ® Replace.
lEngine mounting boss b, crankcase
Cracks/damage ® Replace.
2. Inspect:
lBearing
Rotate inner race with a finger.
Rough spot/seizure ® Replace.
Crankshaft
1. Measure:
lRunout limit a
lConnecting rod big end side clearance
b
lCrank width c
Out of specification ® Replace.
Use the dial gauge and a thickness
gauge.
Dial gauge & stand set:
YU-3097/90890-01252
Standard
Runout
limit:—0.03 mm
(0.0012 in)
Side clear-
ance:0.15 ~ 0.45 mm
(0.0059 ~ 0.0177 in)0.50 mm
(0.02 in)
Crack
width:46.95 ~ 47.00 mm
(1.848 ~ 1.850 in)—

4 - 73
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
TRANSMISSION, SHIFT CAM AND SHIFT FORK
Extent of removal:1 Shift cam and shift fork removal2 Main axle and drive axle removal
Extent of removal Order Part name Q’ty Remarks
TRANSMISSION, SHIFTCAM
AND SHIFT FORK REMOVAL
Preparation for removal Engine Refer to “ENGINE REMOVAL” section.
Separate the crankcase. Refer to “CRANKCASE, CRANKSHAFT
AND BALANCER” section.
1 Shift fork guide bar 1 (short) 1
2 Shift fork guide bar 2 (long) 1
3 Shift cam 1
4 Shift fork 2 (C) 1
5 Shift fork 3 (R) 1
6 Shift fork 1 (L) 1
7 Main axle 1
Refer to “REMOVAL POINTS”.
8 Drive axle 1
9 Push rod 2 1
10 Washer 1
1
2

4 - 77
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
3. Install:
lPlain washer 1
lCirclip 2
NOTE:
lBe sure the circlip sharp-edged corner a is
positioned opposite side to the plain washer
and gear b.
lBe sure the circlip end c is positioned at
axle spline groove d.
New
4. Install:
lPush rod 2
On main axle.
NOTE:
Apply the engine oil on the push rod 2.
5. Install:
lWasher 1
On drive axle.
6. Install:
lMain axle
lDrive axle
Install these in the left crankcase at the
same time.
NOTE:
lApply the lithium soap base grease on the oil
seal lip.
lWhen installing the drive axle into the crank-
case, pay careful attention to the crankcase
oil seal lip.

4 - 78
ENGTRANSMISSION, SHIFT CAM AND SHIFT FORK
Shift cam and shift fork
1. Install:
lShift fork 1 (L) 1
lShift fork 2 (C) 2
lShift fork 3 (R) 3
NOTE:
lMesh the shift fork #1 (L) with the 2nd wheel
gear and #3 (R) with the 4th wheel gear on
the drive axle.
lMesh the shift fork #2 (C) with the 3rd pinion
gear on the main axle.
2. Install:
lShift cam 1
NOTE:
Apply the engine oil on the shift cam.
3. Install:
lShift fork guide bar 1 (short) 1
lShift fork guide bar 2 (long) 2
NOTE:
lApply the engine oil on the guide bars.
lBe sure the long bar is inserted into the shift
forks #1 and #3 and the short one into #2.
4. Check:
lShifter operation
lTransmission operation
Unsmooth operation ® Repair.

5 - 1
CHAS

FRONT WHEEL AND FRONT BRAKE (TT-R125)
EC500000
CHASSIS
FRONT WHEEL AND FRONT BRAKE (TT-R125)
Extent of removal:
1
Front wheel removal
2
Wheel bearing removal
3
Brake shoe plate assembly removal and disassembly
Extent of removal Order Part name Q’ty Remarks
Preparation for removal
FRONT WHEEL AND DRUM
BRAKE
Hold the machine by placing the
suitable stand under the engine.
WARNING

Support the machine securely so there is no
danger of it falling over.
1 Brake cable holder 1
2 Brake cable 1 Disconnect at the lever side, first.
3 Axle nut 1
4 Wheel axle 1
5 Front wheel 1
6 Collar set 1
7 Brake shoe plate assembly 1
8 Oil seal 1
9 Wheel bearing 2 Refer to “REMOVAL POINTS”.
10Spacer
1
2
3
1

5

5 - 8
CHAS
FRONT WHEEL (TT-R125LW)
Extent of removal:1 Front wheel removal2 Wheel bearing removal
3 Brake disc removal
Extent of removal Order Part name Q’ty Remarks
Preparation for removalFRONT WHEEL 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.
1 Axle nut 1
2 Washer 1
3 Wheel axle 1
4 Front wheel 1
5 Collar 2
6 Oil seal 2
7 Wheel bearing 2 Refer to “REMOVAL POINTS”.
8 Spacer 1
9Brake disk
1
2
31
3
FRONT WHEEL (TT-R125LW)