weight YAMAHA YZ125LC 2002 Owners Manual

EC050000
TO THE NEW OWNER
This manual will provide you with a good basic
understanding of features, operation, and basic
maintenance and inspection items of this ma-
chine. Please read this manual carefully and
completely before operating your new machine.
If you have any questions regarding the opera-
tion or maintenance of your machine, please
consult your Yamaha dealer.
NOTE:
This manual should be considered a permanent
part of this machine and should remain with it
even if the machine is subsequently sold.
EC060000
NOTICE
Some data in this manual may become out-
dated due to improvements made to this
model in the future. If there is any question
you have regarding this manual or your
machine, please consult your Yamaha
dealer.
Weights of machines without fuel
The minimum weights for motocross ma-
chines are:
for the class 125 cc ........................minimum
88 kg (194 lb)
for the class 250 cc ........................minimum
98 kg (216 lb)
for the class 500 cc ........................minimum
102 kg (225 lb)
In modifying your machine (e.g., for weight
reduction), take note of the above limits of
weight.
EC070001
F.I.M. MACHINE WEIGHTS:
5NY-9-30-0 5/23/01 8:00 PM Page 8

EC085002
ILLUSTRATED SYMBOLS
(Refer to the illustration)
Illustrated symbols 1to 7are designed as
thumb tabs to indicate the chapter’s number and
content.
1
General information
2Specifications
3Regular inspection and adjustments
4Engine
5Chassis
6Electrical
7Tuning
Illustrated symbols 8to rare used to identify
the specifications appearing in the text.
8
With engine mounted
9Special tool
0Filling fluid
qLubricant
wTightening
eSpecified value, Service limit
rResistance (Ω), Voltage (V), Electric current (A)
Illustrated symbols tto oin the exploded dia-
grams indicate grade of lubricant and location of
lubrication point.
t
Apply transmission oil
yApply engine mixing oil
uApply molybdenum disulfide oil
iApply lightweight lithium-soap base grease
oApply molybdenum disulfide grease
Illustrated symbols pto ain the exploded dia-
grams indicate where to apply a locking agent
and where to install new parts.
p
Apply locking agent (LOCTITER)
aUse new one
GEN
INFO
12
3
5
74
6
8
90
qw
er
tyu
io
pa
SPEC
INSP
ADJENG
CHASELEC
TUN
5NY-9-30-0 5/23/01 8:01 PM Page 14

1-4
GEN
INFO
IMPORTANT INFORMATION
EC133000
GASKETS, OIL SEALS AND O-RINGS
1. All gaskets, oil seals, and O-rings should be
replaced when an engine is overhauled. All
gasket surfaces, oil seal lips, and O-rings
must be cleaned.
2. Properly oil all mating parts and bearings
during reassembly. Apply grease to the oil
seal lips.
EC134000
LOCK WASHERS/PLATES AND COTTER
PINS
1. All lock washers/plates 1and cotter pins
must be replaced when they are removed.
Lock tab(s) should be bent along the bolt or
nut flat(s) after the bolt or nut has been
properly tightened.
EC135001
BEARINGS AND OIL SEALS
1. Install the bearing (s) 1and oil seal (s) 2
with their manufacturer’s marks or numbers
facing outward. (In other words, the
stamped letters must be on the side ex-
posed to view.) When installing oil seal(s),
apply a light coating of light-weight lithium
base grease to the seal lip(s). Oil the bear-
ings liberally when installing.
cC
Do not use compressed air to spin the
bearings dry. This causes damage to the
bearing surfaces.
EC132000
ALL REPLACEMENT PARTS
1. We recommend to use Yamaha genuine
parts for all replacements. Use oil and/or
grease recommended by Yamaha for as-
sembly and adjustment.
5NY-9-30-1A 5/24/01 7:32 PM Page 8

2-1
SPECGENERAL SPECIFICATIONS
Model name: YZ125LC (EUROPE)
YZ125P1 (USA)
YZ125(P) (CDN, AUS, NZ, ZA)
Model code number: 5NY1 (USA, CDN, ZA)
5NY2 (EUROPE)
5NY4 (AUS, NZ)
Dimensions:USA, ZAAUS, NZ EUROPE CDN
Overall length 2,134 mm←2,130 mm←
(84.0 in) (83.9 in)
Overall width 827 mm←←←
(32.6 in)
Overall height 1,318 mm 1,315 mm 1,311 mm 1,315 mm
(51.9 in) (51.8 in) (51.6 in) (51.8 in)
Seat height 993 mm←992 mm←
(39.1 in) (39.1 in)
Wheelbase 1,438 mm←←←
(56.6 in)
Minimum ground clearance 400 mm←398 mm←
(15.7 in) (15.7 in)
Basic weight:
With oil and full fuel tank 95.0 kg (209.4 lb)
Engine:
Engine type Liquid cooled 2-stroke, gasoline
Cylinder arrangement Single cylinder, forward inclined
Displacement 124 cm
3(4.36 lmp oz, 4.19 US oz)
Bore ×Stroke 54 ×54.5 mm (2.126 ×2.146 in)
Compression ratio 8.7~10.8 : 1
Starting system Kick starter
Lubrication system: Premix (30 : 1)(Yamalube 2-R)
Oil type or grade (2-Cycle):
Transmission oil Yamalube 4 (10W-30) or SAE 10W-30 type SE
motor oil
Periodic oil change 0.65 L (0.57 Imp qt, 0.69 US qt)
Total amount 0.70 L (0.62 Imp qt, 0.74 US qt)
Coolant capacity (including all routes): 0.95 L (0.84 Imp qt, 1.00 US qt)
Air filter: Wet type element
Fuel:
Type Except for ZA: Premium unleaded gasoline
only with a research octane
number of 95 or higher
For ZA: Premium gasoline
Tank capacity 8.0 L (1.76 Imp gal, 2.11 US gal)
EC200000
SPECIFICATIONSEC211000
GENERAL SPECIFICATIONS
2
5NY-9-30-2A 5/24/01 8:03 PM Page 2

2-12
SPEC
GENERAL TORQUE SPECIFICATIONS/
DEFINITION OF UNITS
This chart specifies torque for standard faste-
ners with standard I.S.O. pitch threads. Torque
specifications for special components or assem-
blies are included in the applicable sections of
this book. To avoid warpage, tighten multi-faste-
ner assemblies in a crisscross fashion, in pro-
gressive stages, until full torque is reached.
Unless otherwise specified, torque specifications
call for clean, dry threads. Components should
be at room temperature.
A: Distance across flats
B: Outside thread diameter
EC230000
DEFINITION OF UNITS
EC220001
GENERAL TORQUE SPECIFICATIONS
A B TORQUE SPECIFICATION
(Nut) (Bolt)
Nm m•kg ft•lb
10 mm 6 mm 6 0.6 4.3
12 mm 8 mm 15 1.5 11
14 mm 10 mm 30 3.0 22
17 mm 12 mm 55 5.5 40
19 mm 14 mm 85 8.5 61
22 mm 16 mm 130 13 94
Unit Read Definition Measure
mm milimeter 10-
3meter Length
cm centimeter 10-2meter Length
kg kilogram 103gram Weight
N Newton 1 kg ×m/sec2Force
Nm Newton meter N ×m Torque
m•kg Meter kilogrma m ×kg Torque
Pa Pascal N/m2Pressure
N/mm Newton per millimeter N/mm Spring rate
L Liter — Volume or capacity
cm3Cubic centimeter — Volume or capacity
r/min Revolution per minute — Engine speed
5NY-9-30-2A 5/24/01 8:03 PM Page 13

3-37
LUBRICATION
INSP
ADJ
EC36a042
LUBRICATION
To ensure smooth operation of all components,
lubricate your machine during setup, after break-
in, and after every race.
1All control cable
2Clutch lever pivot
3Shift pedal pivot
4Footrest pivot
5Throttle-to-handlebar contact
6Drive chain
7Throttle roller sliding surface
8Tube guide cable winding portion
9Throttle cable end
0Clutch cable endÅUse Yamaha cable lube or equivalent on
these areas.
ıUse SAE10W-30 motor oil or suitable chain
lubricants.
ÇLubricate the following areas with high quali-
ty, lightweight lithium-soap base grease.
cC
Wipe off any excess grease, and avoid get-
ting grease on the brake discs.
A
A
CC
AB
AA
5NY-9-30-3B 5/23/01 8:34 PM Page 38

4-46
ENGYPVS GOVERNOR
Extent of removal Order Part name Q’ty Remarks
YPVS GOVERNOR REMOVAL
Preparation for Crankcase cover (right)
Refer to “KICK AXLE, SHIFT SHAFT AND
removalPRIMARY DRIVE GEAR” section.
1 Governor assembly 1
2 Dowel pin 1 Refer to “REMOVAL POINTS”.
3 Retainer 1
4 Ball 4
5 Retainer weight 1
6 Plain washer 4
7 Thrust bearing 2
8 Collar 1
9 Plate 1
10 Compression spring 1
11 Governor gear 1
12 Governor shaft 1
EC4K0000
YPVS GOVERNOR
1
Extent of removal:1YPVS governor removal and disassembly
5 Nm (0.5 m•kg, 3.6 ft•lb)
5NY-9-30-4C 5/23/01 8:56 PM Page 18

4-47
ENGYPVS GOVERNOR
EC4K3000
REMOVAL POINTS
EC4K3100
Governor
1. Remove:
9Dowel pin 1
NOTE:
While compressing the spring, remove the dowel
pin.
EC4K4000
INSPECTION
EC4K4100
Governor groove
1. Inspect:
9Plain washer 1
9Collar 2
Wear/Damage Replace.
EC4K4200
Bearing
1. Inspect:
9Thrust bearing 1
9Plain washer 2
Wear/Damage Replace.
EC4K5000
ASSEMBLY AND INSTALLATION
EC4K5120
Governor
1. Install:
9Governor gear 1
9Compression spring 2
9Plate 3
9Plain washer 4
9Thrust bearing 5
9Collar 6
9Retainer weight 7
To governor shaft 8.
NOTE:
Apply the lithium soap base grease on the thrust
bearing.
5NY-9-30-4C 5/23/01 8:56 PM Page 20

7-17
TUNSETTING
2. Use of stiff spring
Generally a stiff spring gives a stiff riding
feeling. Rebound damping tends to become
weaker, resulting in lack of a sense of con-
tact with the road surface or in a vibrating
handlebar.
To set a stiff spring:
9Change the rebound damping.
Turn in one or two clicks.
9Change the compression damping.
Turn out one or two clicks.
åCoverage of spring by weight
∫Rider weight
1Soft
2Standard
3Stiff
5NY-9-30-7B 5/23/01 9:22 PM Page 10

7-21
TUNSETTING
cC
When using a rear cushion other than cur-
rently installed, use the one whose overall
length
a a
does not exceed the standard as
it may result in faulty performance. Never
use one whose overall length is greater
than standard.
åCoverage of spring by weight
∫Rider weight
1Soft
2Standard
3Stiff
Length a a
of standard shock:
490.5 mm (19.31 in)
5NY-9-30-7B 5/23/01 9:22 PM Page 18