2001 YAMAHA YZ250LC light

INSP
ADJ
3-14
PILOT AIR SCREW ADJUSTMENT
4. Remove:
9Oil drain bolt 1
9Oil filler cap 2
Drain the transmission oil.
5. Install:
9Aluminum washer
9Oil drain bolt 1
6. Fill:
9Transmission oil
Recommended oil:
Yamalube 4 (10W-30) or SAE
10W-30 type SE motor oil
Oil capacity
(periodic oil change):
0.75 L (0.66 Imp qt, 0.79 US qt)
20 Nm (2.0 m•kg, 14 ft•lb)
7. Check:
9Oil leakage
8. Check:
9Transmission oil level
9. Install:
9Oil filler cap 2
EC35L021
PILOT AIR SCREW ADJUSTMENT
1. Adjust:
9Pilot air screw 1
Adjusting steps:
9Turn in the pilot air screw until it is lightly
seated.
9Turn out the pilot air screw by the factory-set
number of turns.
NOTE:
To optimize the fuel flow at a smaller throttle
opening, each machine’s pilot air screw has
been individually set at the factory. Before
adjusting the pilot air screw, turn it in fully and
count the number of turns. Record this num-
ber as the factory-set number of turns out.
Pilot air screw:
1 turn out
*1-3/4 turns out
(for reference only)
*For EUROPE
5MW-9-30-3A 7/3/00 2:52 PM Page 36

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 endUse Yamaha cable lube or equivalent on
these areas.
õUse SAE10W-30 motor oil or suitable chain
lubricants.
‚Lubricate the following areas with high quali-
ty, lightweight lithium-soap base grease.
cC
Wipe off any excess grease, and avoid getting
grease on the brake discs.
A
A
CC
AB
AA
5MW-9-30-3B 7/3/00 3:30 PM Page 42

3-38
ELECTRICAL/SPARK PLUG INSPECTION
INSP
ADJ
EC370000
ELECTRICAL
EC371001
SPARK PLUG INSPECTION
1. Remove:
9Spark plug
2. Inspect:
9Electrode 1
Wear/Damage ÕReplace.
9Insulator color 2
Normal condition is a medium to light tan
color.
Distinctly different color ÕCheck the
engine condition.
NOTE:
When the engine runs for many hours at low
speeds, the spark plug insulator will become
sooty, even if the engine and carburetor are in
good operating condition.
3. Measure:
9Plug gap a
Use a wire gauge or thickness gauge.
Out of specification ÕRegap.
4. Clean the plug with a spark plug cleaner if
necessary.
5. Tighten:
9Spark plug
NOTE:
9Before installing a spark plug, clean the
gasket surface and plug surface.
9Finger-tighten athe spark plug before torquing
to specification b.
Spark plug gap:
0.5~0.6 mm (0.020~0.024 in)
Standard spark plug:
BR8EG (NGK)
20 Nm (2.0 m•kg, 14 ft•lb)
5MW-9-30-3B 7/3/00 3:30 PM Page 44

ENG
3. Install:
9Pilot air screw 1
9Throttle stop screw 2
*For EUROPE
4. Install:
9Starter plunger 1
4-14
CARBURETOR AND REED VALVE
Pilot air screw:
1 turn out
*1-3/4 turns out
(for reference only)
Note the following installation points:
9Turn in the pilot air screw until it is lightly
seated.
9Turn out the pilot air screw by the number of
turns recorded before removing.
5. Install:
9Pilot jet 1
9Main jet 2
6. Install:
9Needle valve 1
9Float 2
9Float pin 3
NOTE:
9After installing the needle valve to the float,
install them to the carburetor.
9Check the float for smooth movement.
7. Install:
9Float chamber 1
9Plate 2
9Screw (float chamber) 3
5MW-9-30-4A 7/3/00 5:24 PM Page 28

4-65
CRANKCASE AND CRANKSHAFTENG
NOTE:
9Fully 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.
9As pressure is applied, alternately tap on the
front engine mounting boss and transmission
shafts.
cC
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,
realign, and start over. If the cases do not
separate, check for a remaining case screw
or fitting. Do not force.
EC4N3000
REMOVAL POINTS
EC4N3100
Segment
1. Remove:
9Bolt (segment) 1
9Segment 2
NOTE:
Turn the segment counterclockwise until it stops
and loosen the bolt.
EC4N3211
Crankcase
1. Remove:
9Crankcase (right) 1
Use the crankcase separating tool 2and
crankcase separating bolt 3.
Crankcase separating tool:
YU-1135-A/90890-01135
Crankcase separating bolt:
YM-1305/90890-01305
5MW-9-30-4C 7/4/00 9:25 AM Page 34

4-69
CRANKCASE AND CRANKSHAFTENG
3. Install:
9O-ring 1
To crankcase (right) 2.
5. Install:
9Dowel pin 1
9Crankcase (right) 2
To crankcase (left) 3.
NOTE:
9Fit the crankcase (right) onto the crankcase
(left). Tap lightly on the case with soft hammer.
9When installing the crankcase, the connecting
rod should be positioned at TDC (top dead
center).
6. Install:
9Bolt (crankcase) 1
NOTE:
Tighten the crankcase tightening bolts in stage,
using a crisscross pattern.
NOTE:
Clean the contacting surface of crankcase (left
and right) before applying the sealant.
4. Apply:
9Sealant
On the crankcase (right) 1.
Quick gasket®:
ACC-QUICK-GS-KT
Yamaha bond No. 1215:
90890-85505
14 Nm (1.4 m•kg, 10 ft•lb)
5MW-9-30-4C 7/4/00 9:29 AM Page 42

4-72
TRANSMISSION, SHIFT CAM AND SHIFT FORKENG
EC4H4600
Bearing
1. Inspect:
9Bearing 1
Rotate inner race with a finger.
Rough spot/Seizure
ÕReplace. 2. Check:
9Gears movement
Unsmooth movement
ÕRepair or replace.
EC4H4000
INSPECTION
EC4H4200
Gears
1. Inspect:
9Matching dog a
9Gear teeth b
9Shift fork groove c
Wear/Damage
ÕReplace.
EC4H3000
REMOVAL POINTS
EC4H3230
Transmission
1. Remove:
9Main axle 1
9Drive axle 2
9Shift cam
9Shift fork 3
9Shift fork 2
9Shift fork 1
NOTE:
9Remove assembly carefully. Note the position
of each part. Pay particular attention to the
location and direction of shift forks.
9Remove the main axle, drive axle, shift cam
and shift fork all together by tapping lightly on
the transmission drive axle with a soft hammer.
5MW-9-30-4C 7/4/00 9:31 AM Page 48

5-18
CHASFRONT BRAKE AND REAR BRAKE
3. Install:
9Brake hose holder 1
9Caliper 2
9Bolt (caliper) 3
NOTE:
Fit the brake hose holder cut aover the projec-
tion bon the front fork and clamp the brake
hose.
4. Tighten:
9Pad pin 4
5. Install:
9Pad pin plug 5
EC5A5120
Rear caliper
1. Install:
9Pad support 1
9Brake pad 2
9Pad pin 3
NOTE:
9Install the brake pads with their projections
ainto the caliper recesses b.
9Temporarily tighten the pad pin at this point.
2. Install:
9Copper washer 1
9Union bolt 2
w
Always use new copper washers.
cC
Install the brake hose so that its pipe por-
tion a a
directs as show and lightly touches
the projection b b
on the caliper.
30 Nm (3.0 m•kg, 22 ft•lb)
23 Nm (2.3 m•kg, 17 ft•lb)
18 Nm (1.8 m•kg, 13 ft•lb)
3 Nm (0.3 m•kg, 2.2 ft•lb)
5MW-9-30-5A 7/6/00 8:55 AM Page 36