engine oil YAMAHA YZ250LC 2001 User Guide

2-13
CABLE ROUTING DIAGRAMSPEC
EC240000
CABLE ROUTING DIAGRAM
1Cable guide
2Clamp
3“ENGINE STOP” button lead
4Throttle cable
5TPS (throttle position sensor)
lead
6Solenoid valve lead
7CDI unit
8CDI unit stay
9CDI unit band
0Air vent hose (left)
qTransmission oil breather hose
wOverflow hose
eAir vent hose (right)APass the throttle cable and
“ENGINE STOP” button lead into
the cable guide. Align with the
cable guide the front end of the
tape on the throttle cable.
BClamp the throttle cable,
“ENGINE STOP” button lead and
CDI unit lead with the clamp
ends downward.
CPass the throttle cable, “ENGINE
STOP” button lead and CDI unit
lead over the radiator hose.
DClamp the clutch cable, throttle
cable, “ENGINE STOP” button
lead, TPS (throttle position sen-
sor) lead and solenoid valve lead
with the clamp ends downward.
In so doing, clamp the “ENGINE
STOP” button lead at its protect-
ing tube.
EClamp the clutch cable so that
the clamp passes with its ends
downward, as shown.
FPass the TPS (throttle position
sensor) lead and solenoid valve
lead through the cable guide.GClamp the TPS (throttle position
sensor) lead and solenoid valve
lead to the frame with the clamp
ends backward.
HPass the solenoid valve lead
through the carburetor clamp.
IPass the air vent hoses, overflow
hose and transmission oil
breather hose between the frame
and connecting rod.
JFit the CDI unit into the CDI unit
stay till it stops.
KInsert the CDI unit into the CDI
unit band till it stops.
LPass the TPS (throttle position
sensor) lead and solenoid valve
lead under the damper.
MClamp the air vent hoses.
NPass the air vent hoses, overflow
hose and transmission oil
breather hose so that all these
hoses do not contact the rear
shock absorber.
5MW-9-30-2 7/3/00 2:24 PM Page 50

2-15
CABLE ROUTING DIAGRAMSPEC
1Brake hose holder
2Master cylinder
3Brake hose
4Reservoir hose
5Hose guide
6Clamp
7High tension cord
8Ignition coil
9Clutch cable
0Cable guide
qGround lead
wRadiator breather hose
eCDI magneto lead
rThrottle cable
tCDI unit lead
y“ENGINE STOP” button lead
uFuel tank damper
iEngine bracket
APass the brake hose into the
brake hose holder.BIf the brake hose contacts the
spring (rear shock absorber),
correct its twist.
CInstall the brake hose so that its
pipe portion directs as shown
and lightly touches the projec-
tion on the master cylinder.
DPass the reservoir hose
between the brake hose and
swingarm bracket.
EPass the reservoir hose into the
hose guide.
FClamp the high tension cord,
throttle cable, TPS (throttle posi-
tion sensor) and solenoid valve
lead so that the high tension
cord does not contact the
engine bracket installation nuts.
G
Fasten the ground lead together
with the front installation portion
of the ingnition coil.
HPass the clutch cable into the
cable guide.
IPosition the CDI magneto lead
coupler between the radiators.
JInstall the brake hose to the
caliper with the paint on the pipe
facing the caliper and with the
pipe contacting the caliper pro-
jection.
KPass the radiator breather hose
between the frame and radiator
hose so that it is not kinked or
wedged.
LPass the throttle cable, CDI unit
lead, “ENGINE STOP” button
lead and clutch cable between
the fuel tank damper tube ends.
5MW-9-30-2 7/3/00 2:26 PM Page 54

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
P7-1~24
results of test runs before racing? Are inspection and
maintenance completely done?
5MW-9-30-3A 7/3/00 2:47 PM Page 14

INSP
ADJ
3-7
RADIATOR CAP INSPECTION
cC
9Do not mix more than one type of ethyl-
ene glycol antifreeze containing corro-
sion inhibitors for aluminum engine.
9Do not use water containing impurities
or oil.
7. Install:
9Radiator cap
Start the engine and warm it up for a sev-
eral minutes.
8. Check:
9Coolant level
Coolant level lowÕAdd coolant.
EC355000
RADIATOR CAP INSPECTION
1. Inspect:
9Seal (radiator cap) 1
9Valve and valve seat 2
Crack/DamageÕReplace.
Exist fur deposits 3ÕClean or replace.
Handling notes of coolant:
The coolant is harmful so it should be handled
with special care.
w
9When coolant splashes to your eye.
Thoroughly wash your eye with water
and see your doctor.
9When coolant splashes to your clothes.
Quickly wash it away with water and then
with soap.
9When coolant is swallowed.
Quickly make him vomit and take him to
a doctor.
5MW-9-30-3A 7/3/00 2:48 PM Page 22

INSP
ADJ
3-12
TRANSMISSION OIL LEVEL CHECK
3. Inspect:
9Air filter element
DamageÕReplace.
4. Apply:
9Foam-air-filter oil or engine mixing oil
To the element.
NOTE:
Squeeze out the excess oil. Element should be
wet but not dripping.
5. Install:
9Filter guide 1
NOTE:
Align the projection aon filter guide with the
hole bin air filter element.
6. Apply:
9Lithium soap base grease
On the matching surface aon air filter ele-
ment.
7. Install:
9Air filter element 1
9Washer
9Fitting bolt
NOTE:
Align the projection aon filter guide with the
hole bin air filter case.
EC35H002
TRANSMISSION OIL LEVEL CHECK
1. Start the engine, warm it up for several min-
utes and wait for five minutes.
2. Place the machine on a level place and hold
it up on upright position by placing the suit-
able stand under the engine.
2 Nm (0.2 m•kg, 1.4 ft•lb)
5MW-9-30-3A 7/3/00 2:51 PM Page 32

INSP
ADJ
3-13
TRANSMISSION OIL REPLACEMENT
3. Check:
9Transmission oil level
EC35K002
TRANSMISSION OIL REPLACEMENT
1. Start the engine and warm it up for several
minutes and wait for five minute.
2. Place the machine on a level place and hold
it on upright position by placing the suitable
stand under the engine.
3. Place a suitable container under the engine.
Transmission oil level checking steps:
9Remove the oil check bolt 1.
9Inspect the oil level.
NOTE:
Be sure the machine is positioned straight
up when inspecting the oil level.
w
Never attempt to remove the oil check bolt
just after high speed operation. The heat-
ed oil could spout out, causing danger.
Wait until the oil cools down.
Oil flows outÕOil level is correct.
Oil does not flow outÕOil level is low.
Add transmission
oil until oil flows
out.
9Inspect the gasket (oil check bolt), replace if
damaged.
9Tighten the oil check bolt.
Recommended oil:
Yamalube 4 (10W-30) or SAE
10W-30 type SE motor oil
Oil check bolt:
10 Nm (1.0 m•kg, 7.2 ft•lb)
5MW-9-30-3A 7/3/00 2:51 PM Page 34

3-25
DRIVE CHAIN SLACK ADJUSTMENT
INSP
ADJ
EC36A060
DRIVE CHAIN SLACK ADJUSTMENT
1. Elevate the rear wheel by placing the suit-
able stand under the engine.
2. Check:
9Drive chain slack a
Above the seal guard installation bolt.
Out of specification ÕAdjust
NOTE:
Before checking and/or adjusting, rotate the rear
wheel through several revolutions and check the
slack several times to find the tightest point. Check
and/or adjust chain slack with rear wheel in this
“tight chain” position.
Drive chain slack:
40~50 mm (1.6~2.0 in)
Drive chain lubricant:
SAE 10W-30 motor oil or suitable
chain lubricants
5. Install:
9Drive chain 1
9Joint 2
9Master link clip 3
cC
Be sure to install the master link clip to the
direction as shown.
aTurning direction
6. Lubricate:
9Drive chain
5MW-9-30-3B 7/3/00 3:23 PM Page 18

3-26
FRONT FORK INSPECTION
INSP
ADJ
3. Adjust:
9Drive chain slack
EC36C000
FRONT FORK INSPECTION
1. Inspect:
9Front fork smooth action
Operate the front brake and stroke the
front fork.
Unsmooth action/oil leakage ÕRepair or
replace.
Drive chain slack adjustment steps:
9Loosen the axle nut 1and locknuts 2.
9Adjust chain slack by turning the
adjusters 3.
To tighten ÕTurn adjuster 3 3
counter-
clockwise.
To loosen ÕTurn adjuster 3 3
clockwise
and push wheel forward.
9Turn each adjuster exactly the same amount
to maintain correct axle alignment. (There are
marks aon each side of chain puller align-
ment.)
NOTE:
Turn the adjuster so that the chain is in line
with the sprocket, as viewed from the rear.
cC
Too small chain slack will overload the
engine and other vital parts; keep the
slack within the specified limits.
9Tighten the axle nut while pushing down the
drive chain.
9Tighten the locknuts.
Axle nut:
125 Nm (12.5 m•kg, 90 ft•lb)
5MW-9-30-3B 7/3/00 3:23 PM Page 20

ENG
2. Install:
9Reed valve assembly 1
9Reed valve spacer 2
NOTE:
Install the reed valve spacer with its chamfered
side ato the right.
3. Install:
9Carburetor joint 1
9Bolt (carburetor joint) 2
4-13
CARBURETOR AND REED VALVE
10 Nm (1.0 m•kg, 7.2 ft•lb)
EC4652F0
Carburetor
1. Install:
9Power jet 1
To carburetor 2.
2. Install:
9O-ring 1
9Solenoid valve 2
9Clamp 3
9Screw (clamp) 4
To carburetor 5.
cC
9Before installing the solenoid valve, blow air
on the solenoid valve and its installing loca-
tion on the carburetor in order to remove
any foreign particles such as chips etc.
9Apply the engine oil on the solenoid valve
thread.
5MW-9-30-4A 7/3/00 5:24 PM Page 26

4-28
CYLINDER HEAD, CYLINDER AND PISTONENG
7. Install:
9O-ring 1
9Side holder 2
9Screw (side holder) 3
9YPVS breather hose 4
NOTE:
9Apply the lithium soap base grease on the O-
rings.
9Install the side holder with its projection a
facing upward.
8. Install:
9Gasket (power valve cover) 1
9Power valve cover 2
9Screw (power valve cover) 3
NOTE:
9Install the gasket with its cut afacing down-
ward and the seal print side toward the power
valve cover.
9Install the power valve cover so that the arrow
mark bfaces upward.
EC475233
Piston ring and piston
1. Install:
9Piston ring 1
NOTE:
9Take care not to scratch the piston or damage
the piston ring.
9Align the piston ring gap with the pin 2.
9After installing the piston ring, check the
smooth movement of it.
2. Install:
9Gasket (cylinder) 1
9Small end bearing 2
9Dowel pin 3
NOTE:
9Apply the engine oil onto the bearing (crank-
shaft and connecting rod) and connecting rod
big end washers.
9Install the gasket with the seal print side toward
the crankcase.
4 Nm (0.4 m•kg, 2.9 ft•lb)
4 Nm (0.4 m•kg, 2.9 ft•lb)
5MW-9-30-4B 7/3/00 6:24 PM Page 4