2000 YAMAHA SR125 engine

PERIODIC MAINTENANCE AND MINOR REPAIR
6-23
6
EAU01106*
Drive chain lubricationThe chain consists of many parts which
work with each other. If the chain is not
maintained properly, it will wear out
quickly. Therefore, the chain must be
serviced regularly. This service is es-
pecially necessary when riding in dusty
areas.
The drive chain should be lubricated
every 500 km. First, remove all dirt and
mud from the chain with a brush or
cloth. Then, spray any of the many
brands of spray-type chain lubricant
between both rows of side plates and
on all center rollers.
To clean the chain thoroughly, remove
it from the motorcycle, dip it in solvent,
and clean out as much dirt as possible.
Then, take the chain out of the solvent
to dry it, and immediately lubricate it to
prevent it from rusting.
EAU02962
Cable inspection and
lubrication
EW000112
WARNING
@ Damage to the outer housing of ca-
bles may lead to internal rusting and
interfere with the cable movement.
Replace damaged cables as soon as
possible to prevent unsafe condi-
tions. @Lubricate the cables and cable ends. If
a cable does not operate smoothly, ask
a Yamaha dealer to replace it.
EAU00773
Throttle cable and grip
lubricationThe throttle twist grip assembly should
be greased at the time that the cable is
lubricated, since the grip must be re-
moved to get at the end of the throttle
cable. After removing the screws, hold
the end of the cable up in the air and
put in several drops of lubricant. With
the throttle grip disassembled, coat the
metal surface of the grip assembly with
a suitable all-purpose grease.
Recommended lubricant:
Engine oil
E_3mw.book Page 23 Monday, February 5, 2001 9:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-24
6
EAU02984
Brake and shift pedal
lubricationLubricate the pivoting parts.
EAU02985
Brake and clutch lever
lubricationLubricate the pivoting parts.
EAU02965
Center and sidestand
lubricationLubricate the pivoting and mating
joints.
Check to see that the center and side-
stand move up and down smoothly. Recommended lubricant:
Engine oil
Recommended lubricant:
Engine oil
Recommended lubricant:
Engine oil
E_3mw.book Page 24 Monday, February 5, 2001 9:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-26
6
EAU00794
Steering inspectionPeriodically inspect the condition of the
steering. Worn out or loose steering
bearings may be dangerous. Place a
stand under the engine to raise the
front wheel off the ground. Hold the
lower end of the front forks and try to
move them forward and backward. If
any free play can be felt, ask a Yamaha
dealer to inspect and adjust the steer-
ing. Inspection is easier if the front
wheel is removed.
EW000115
WARNING
@ Securely support the motorcycle so
there is no danger of it falling over. @
EAU01144
Wheel bearingsIf there is play in the front or rear wheel
hub or if the wheel does not turn
smoothly, have a Yamaha dealer in-
spect the wheel bearings.
EAU01647
BatteryRemove panel A. (See page 6-5 for re-
moval and installation procedures.)
Check the level of the battery electro-
lyte and make sure that the terminals
are tight. Fill with distilled water if the
electrolyte level is low.1. Maximum level mark
2. Minimum level mark
E_3mw.book Page 26 Monday, February 5, 2001 9:54 AM

PERIODIC MAINTENANCE AND MINOR REPAIR
6-34
6
EAU03009
Troubleshooting chart
EW000125
WARNING
@ Never check the fuel system while smoking or in the vicinity of an open flame. @
Check if there is fuel in
the fuel tank.1. Fuel
Enough fuel.
No fuel.
Go to compression check.
Supply fuel.
Engine doesn’t start, go to compression check.
Use the electric starter.2. Compression
There is compression.
No compression.
Go to ignition check.
Ask a Yamaha dealer to
inspect.
Remove spark plug and
check electrodes.3. Ignition
Wet.
Dry.
Wipe clean with dry cloth and correct
spark gap or replace spark plug.
Ask a Yamaha dealer to inspect.
Engine doesn’t start, ask a Yamaha
dealer to inspect.Engine doesn’t start, go to battery
check.Open throttle half-way and start
the engine.
Use the electric starter.4. Battery
Engine turns over
quickly.
Engine turns over
slowly.
Battery good.Check fluid, recharge,
check connections.
E_3mw.book Page 34 Monday, February 5, 2001 9:54 AM

MOTORCYCLE CARE AND STORAGE
7-3
7 After riding in the rain, near the sea or
on salt-sprayed roadsSince sea salt or salt sprayed on the
roads in the winter are extremely corro-
sive in combination with water, carry
out the following steps after each ride
in the rain, near the sea or on salt-
sprayed roads. (Salt sprayed in the
winter may remain on the roads well
into spring.)
1. Clean your motorcycle with cold
water and soap after the engine
has cooled down.
ECA00012
CAUTION:@ Do not use warm water since it in-
creases the corrosive action of the
salt. @2. Be sure to apply a corrosion pro-
tection spray on all (even chrome-
and nickel-plated) metal surfaces
to prevent corrosion.After cleaning
1. Dry the motorcycle with a chamois
or an absorbing cloth.
2. Immediately dry the drive chain
and lubricate it to prevent it from
rusting.
3. Use a chrome polish to shine
chrome, aluminum and stainless-
steel parts, including the exhaust
system. (Even the thermally in-
duced discoloring of stainless-
steel exhaust systems can be re-
moved through polishing.)
4. To prevent corrosion, it is recom-
mended to apply a corrosion pro-
tection spray on all (even chrome-
and nickel-plated) metal surfaces.
5. Use spray oil as a universal clean-
er to remove any remaining dirt.
6. Touch up minor paint damage
caused by stones, etc.
7. Wax all painted surfaces.
8. Let the motorcycle dry completely
before storing it or covering it.
EWA00001
WARNING
@ Make sure that there is no oil or wax
on the brakes and tires. If neces-
sary, clean the brake discs and lin-
ings with a regular brake disc
cleaner or acetone, and wash the
tires with warm water and mild soap.
Then, carefully test the motorcycle
for its braking performance and cor-
nering behavior. @
E_3mw.book Page 3 Monday, February 5, 2001 9:54 AM

MOTORCYCLE CARE AND STORAGE
7-5
7 a. Remove the spark plug cap and
spark plug.
b. Pour a teaspoonful of engine oil
into the spark plug bore.
c. Install the spark plug cap onto the
spark plug and place the spark
plug on the cylinder head so that
the electrodes are grounded. (This
will limit sparking during the next
step.)
d. Turn the engine over several times
with the starter. (This will coat the
cylinder wall with oil.)
e. Remove the spark plug cap from
the spark plug, install the spark
plug and then the spark plug cap.
EWA00003
WARNING
@ When turning the engine over, be
sure to ground the spark plug elec-
trodes to prevent damage or injury
from sparking. @
6. Lubricate all control cables and
the pivoting points of all levers and
pedals as well as of the sidestand/
centerstand.
7. Check and, if necessary, correct
the tire air pressure, then raise the
motorcycle so that both of its
wheels are off the ground. Alterna-
tively, turn the wheels a little every
month in order to prevent the tires
from becoming degraded in one
spot.
8. Cover up the muffler outlet with a
plastic bag to prevent moisture
from entering.9. Remove the battery and fully
charge it. Store it in a cool, dry
place and recharge it once a
month. Do not store the battery in
an excessively cold or warm place
(less than 0 °C or more than
30 °C). For more information, see
“Battery storage” in the chapter
“PERIODIC MAINTENANCE AND
MINOR REPAIRS”.
NOTE:@ Make any necessary repairs before
storing the motorcycle. @
E_3mw.book Page 5 Monday, February 5, 2001 9:54 AM

8-1
8
EAU01038
8-SPECIFICATIONSSpecifications
Model SR125
Dimensions
Overall length 2,020 mm
Overall width 775 mm
Overall height 1,100 mm
Seat height 745 mm
Wheelbase 1,285 mm
Ground clearance 155 mm
Minimum turning radius 2,100 mm
Basic weight (with oil and full
fuel tank)
113 kg
Engine
Engine type Air-cooled 4-stroke, SOHC
Cylinder arrangement Forward-inclined single cylinder
Displacement 124 cm
3
Bore ´ Stroke 57.0 ´ 48.8 mm
Compression ratio 10:1
Starting system Electric starter
Lubrication system Wet sumpEngine oil
Ty p e
Recommended engine oil
classification API Service SE, SF, SG type or
higher
Quantity
Periodic oil change 1.0 L
With oil filter replacement 1.1 L
Total amount 1.3 L
Air filterWet type element
-20˚ -10˚ 0˚
10˚20˚ 30˚
40˚50˚C
SAE 10W/30
SAE 15W/40SAE 20W/40SAE 20W/50
SAE 10W/40
CAUTION:Be sure to use motor oils that do not contain anti-friction
modifiers. Passenger car motor oils (often labeled
“Energy Conserving”) contain anti-friction additives which
will cause clutch and/or starter clutch slippage, resulting in
reduced component life and poor engine performance.
E_3mw.book Page 1 Monday, February 5, 2001 9:54 AM