2001 YAMAHA YZ125LC seat adjustment

3-14
INSP
ADJ
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
7. Check:
9Oil leakage
8. Check:
9Transmission oil level
9. Install:
9Oil filler cap 2
EC35L002
PILOT AIR SCREW ADJUSTMENT
1. Adjust:
9Pilot air screw 1
Recommended oil:
Yamalube 4 (10W-30) or SAE
10W-30 type SE motor oil
Oil capacity
(periodic oil change):
0.65 L (0.57 Imp qt, 0.69 US qt)
Adjustment steps:
9Screw in the pilot air screw until it is
lightly seated.
9Back out by the specified number of
turns.
Pilot air screw:
1-1/4 turns out
*1-1/2 turns out
20 Nm (2.0 m•kg, 14 ft•lb)
*For EUROPE
5MV-9-30-3A 6/19/00 1:52 PM Page 36

3-15
INSP
ADJIDLE SPEED ADJUSTMENT/MUFFLER INSPECTION/
SILENCER FIBER REPLACEMENT
EC35M010
IDLE SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it up.
2. Adjust:
9Idle speed
EC35P010
MUFFLER INSPECTION
1. Inspect:
9O-ring 1
Damage ÕReplace.
EC35R041
SILENCER FIBER REPLACEMENT
1. Remove:
9Seat
9Side cover (right)
9Bolt (silencer) 1
9Silencer 2
9Bolt (fiber) 3
Adjustment steps:
9Loosen the locknut 1.
9Turn the throttle stop screw 2until the
engine runs at the lowest possible speed.
9Tighten the locknut.
To increase idle speed ÕTurn the throttle
stop screw 2 2
in.
To decrease idle speed ÕTurn the throttle
stop screw 2 2
out.
5MV-9-30-3A 6/19/00 1:52 PM Page 38

4-11
ENGCARBURETOR AND REED VALVE
Measurement and adjustment steps:
9Remove the drain plug.
9Connect the fuel level gauge adapter 2and
fuel level gauge 1to the float chamber.
Fuel level gauge adapter:
YM-01470/90890-01470
Fuel level gauge:
YM-1312-A/90890-01312
9Hold the fuel level gauge vertically next to
the float chamber mating surface.
9Measure the fuel level with the fuel level
gauge.
NOTE:
Keep the carburetor and fuel level gauge ver-
tically when measuring the fuel level.
9If the fuel level is not within specification, in-
spect the valve seat and needle valve.
9If either is worn, replace them both.
9If both are fine, adjust the fuel level by bend-
ing the float tab bon the float.
9Recheck the fuel level.
EC464802
Fuel level
1. Measure:
9Fuel level a
Out of specification ÕAdjust.
Fuel level:
13.5~14.5 mm (0.53~0.57 in)
Above the float chamber
mating surface
EC464A00
Filter
1. Inspect:
9Filter 1
Damage Õ Replace.
NOTE:
Inspect the filter as it is assembled to the carbu-
retor. Do not remove the filter except when
replacing it.
5MV-9-30-4A 6/19/00 1:47 PM Page 22

7-19
TUNSETTING
EC72B000
Rear suspension setting
The rear suspension setting should be made
depending on the rider’s feeling of an actual run
and the circuit conditions.
The rear suspension setting includes the follow-
ing two factors:
1. Setting of spring preload
9Change the set length of the spring.
9Change the spring.
2. Setting of damping force
9Change the rebound damping.
9Change the compression damping.
EC72C001
Choosing set length
1. Place a stand or block under the engine to
put the rear wheel above the floor, and mea-
sure the length abetween the rear wheel
axle center and the rear fender holding bolt.
2. Remove the stand or block from the engine
and with a rider astride the seat, measure
the sunken length bbetween the rear wheel
axle center and the rear fender holding bolt.
3. Loosen the locknut 1and make adjustment
by turning the spring adjuster 2to achieve
the standard figure from the subtraction of
the length bfrom the length a.
Standard figure:
90~100 mm (3.5~3.9 in)
5MV-9-30-7B 6/19/00 1:23 PM Page 14

7-23
TUNSETTING
EC72H010
Suspension setting
9Front fork
NOTE:
9If any of the following symptoms is experienced with the standard position as the base, make reset-
ting by reference to the adjustment procedure given in the same chart.
9Before any change, set the rear shock absorber sunken length to the standard figure 90~100 mm
(3.5~3.9 in).
Section
Symptom
JumpLarge
Medium Small Check Adjust
gap gap gap
Compression damping Turn adjuster counterclockwise (about 2 clicks)
Stiff over entire to decrease damping.
range111Oil level (oil amount) Decrease oil level by about 5~10 mm (0.2~0.4
in).
Spring Replace with soft spring.
Unsmooth Outer tube Check for any bends, dents, and other notice-
movement over 1111Inner tube able scars, etc. If any, replace affected parts.
entire range
Under bracket tightening Retighten to specified torque.
torque
Poor initial Rebound damping Turn adjuster counterclockwise (about 2 clicks)
movement1to decrease damping.
Oil seal Apply grease in oil seal wall.
Compression damping Turn adjuster clockwise (about 2 clicks) to in-
Soft over entire crease damping.
range, bottoming 11Oil level (oil amount) Increase oil level by about 5~10 mm (0.2~0.4
outin).
Spring Replace with stiff spring.
Stiff toward stroke
1Oil level (oil amount) Decrease oil level by about 5 mm (0.2 in).
end
Soft toward stroke
1Oil level (oil amount) Increase oil level by about 5 mm (0.2 in).
end, bottoming out
Stiff initial
1111Compression dampingTurn adjuster counterclockwise (about 2 clicks)
movement to decrease damping.
Compression damping Turn adjuster clockwise (about 2 clicks) to in-
crease damping.
Low front, tending Rebound damping Turn adjuster counterclockwise (about 2 clicks)
to lower front 11to decrease damping.
postureBalance with rear end Set sunken length for 95~100 mm (3.7~3.9 in)
when one passenger is astride seat (lower rear
posture).
Oil level (oil amount) Increase oil level by about 5 mm (0.2 in).
Compression damping Turn adjuster counterclockwise (about 2 clicks)
to decrease damping.
“Obtrusive” front, Balance with rear end Set sunken length for 90~95 mm (3.5~3.7 in)
tending to upper 11when one passenger is astride seat (upper rear
front postureposture).
Spring Replace with soft spring.
Oil lever (oil amount) Decrease oil level by about 5~10 mm (0.2~0.4
in).
5MV-9-30-7B 6/19/00 1:23 PM Page 22

7-24
TUNSETTING
9Rear shock absorber
NOTE:
9If any of the following symptoms is experienced with the standard position as the base, make reset-
ting by reference to the adjustment procedure given in the same chart.
9Adjust the rebound damping in 2-click increments or decrements.
9Adjust the low compression damping in 1-click increments or decrements.
9Adjust the hight compression damping in 1/6 turn increments or decrements.
Section
Symptom
JumpLarge
Medium Small Check Adjust
gap gap gap
Rebound damping Turn adjuster counterclockwise (about 2 clicks)
Stiff, tending to
11to decrease damping.
sink Spring set length Set sunken length for 90~100 mm (3.5~3.9 in)
when one passenger is astride seat.
Rebound damping Turn adjuster clockwise (about 2 clicks) to in-
Spongy and crease damping.
unstable11Low compression Turn adjuster clockwise (about 1 click) to in-
damping crease damping.
Spring Replace with stiff spring.
Heavy and Rebound damping Turn adjuster counterclockwise (about 2 clicks)
dragging11to decrease damping.
Spring Replace with soft spring.
Rebound damping Turn adjuster counterclockwise (about 2 clicks)
to decrease damping.
Low compression Turn adjuster clockwise (about 1 click) to in-
damping crease damping.
Poor road gripping1High compression Turn adjuster clockwise (about 1/6 turn) to
damping increase damping.
Spring set length Set sunken length for 90~100 mm (3.5~3.9 in)
when one passenger is astride seat.
Spring Replace with soft spring.
High compression Turn adjuster clockwise (about 1/6 turn) to in-
damping crease damping.
Bottoming out11Spring set length Set sunken length for 90~100 mm (3.5~3.9 in)
when one passenger in astride seat.
Spring Replace with stiff spring.
Rebound damping Turn adjuster clockwise (about 2 clicks) to in-
Bouncing11crease damping.
Spring Replace with soft spring.
High compression Turn adjuster counterclockwise (about 1/6
damping turn) to decrease damping.
Stiff travel11Spring set length Set sunken length for 90~100 mm (3.5~3.9 in)
when one passenger is astride seat.
Spring Replace with soft spring.
5MV-9-30-7B 6/19/00 1:23 PM Page 23