2004 YAMAHA YZ250LC seat adjustment

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
*7/8 turns out
(for reference only)
*For EUROPE
5XF-9-30-3A 4/21/03 2:09 PM Page 36

4-11
ENGCARBURETOR AND REED VALVE
EC464401
Jet needle
1. Inspect:
9Jet needle 1
Bends/Wear Replace.
9Clip groove
Free play exists/Wear Replace.
9Clip position
*For EUROPE
EC464511
Float height
1. Measure:
9Float height a
Out of specification Adjust.
Standard clip position:
No.2 Groove
*No.3 Groove
Float height:
5.5~7.5 mm (0.22~0.30 in)
Measurement and adjustment steps:
9Hold the carburetor in an upside down posi-
tion.
9Measure the distance between the mating
surface of the float chamber and top of the
float using a vernier calipers.
NOTE:
The float arm should be resting on the nee-
dle valve, but not compressing the needle
valve.
9If the float height is not within specification,
inspect the valve seat and needle valve.
9If either is worn, replace them both.
9If both are fine, adjust the float height by
bending the float tab bon the float.
9Recheck the float height.
5XF-9-30-4A 5/7/03 1:35 PM Page 22

7-16
SETTINGTUN
EC727030
Spring preload adjustment
The spring preload is adjusted by installing the
adjustment washer 1between the spring seat 2
and fork spring 3.
cC
Do not install three or more adjustment
washers for each front fork.
w
Always adjust each front fork to the same
setting. Uneven adjustment can cause
poor handling and loss of stability.
åLoad
∫Fork stroke
aWithout adjustment washer (standard)
b1 adjustment washer
c2 adjustment washers
EC72A001
Setting of spring after replacement
As the front fork setting can be easily affected by
rear suspension, take care so that the machine
front and rear are balanced (in position, etc.)
when setting the front fork.
1. Use of soft spring
Generally a soft spring gives a soft riding
feeling. Rebound damping tends to become
stronger and the front fork may sink deeply
over a series of gaps.
To set a soft spring:
9Change the rebound damping.
Turn out one or two clicks.
9Change the compression damping.
Turn in one or two clicks.
Standard washer quantity:
Zero adjustment washers
Extent of adjustment:
Zero ~ 2 adjustment washers
5XF-9-30-7 4/22/03 8:56 AM Page 36

7-19
SETTINGTUN
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)
5XF-9-30-7 4/22/03 8:56 AM Page 42

7-23
SETTINGTUN
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).
5XF-9-30-7 4/22/03 8:56 AM Page 50

7-24
SETTINGTUN
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.
Spongy and Rebound damping Turn adjuster clockwise (about 2 clicks) to in-
unstablecrease damping.
11Low 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.
5XF-9-30-7 4/22/03 8:56 AM Page 51