Page 39 of 142

4-14
4
EBU30050Adjusting the front shock absorber as-
semblies (YFM25RSEA/YFM250RSEA)These shock absorber assemblies are equipped
with a spring preload adjusting nut, a rebound
damping force adjusting screw, with a compres-
sion damping force adjusting bolt (for fast com-
pression damping), and a compression damping
force adjusting screw (for slow compression damp-
ing).
WARNING
EWB02491Suspension components become hot during
operation. Never touch the compression
damping force adjusting bolt and screw, the
rebound damping force adjusting screw or
the oil reservoir with your bare hand or skin
until suspension components have cooled.
Always adjust the shock absorber assem-
blies on the left and right side to the same
setting. Uneven adjustment can cause poor
handling and loss of stability, which could
lead to an accident.NOTICEECB00090Never turn an adjusting mechanism beyond
the minimum and maximum settings.TIPAlthough the total number of clicks or turns of a
damping force adjusting mechanism may not ex-
actly match the following specifications due to
small differences in production, the actual number
of clicks or turns always represents the entire ad-
justing range. To obtain a precise adjustment, it
would be advisable to check the number of clicks
or turns of each damping force adjusting mecha-
nism and to modify the specifications as neces-
sary.Spring preload
1. Loosen the locknut. Spring preload setting:
Minimum (soft):
1
Standard:
2
Maximum (hard):
5
U1BT61E0.book Page 14 Tuesday, April 6, 2010 1:28 PM
Page 40 of 142
4-15
42. Turn the spring preload adjusting nut in direc-
tion (a) to increase the spring preload and
thereby harden the suspension, and in direc-
tion (b) to decrease the spring preload and
thereby soften the suspension.
TIPA special wrench can be obtained at a Yamaha
dealer to make this adjustment.The spring preload setting is determined by
measuring distance A, shown in the illustration.
The shorter distance A is, the higher the spring
preload; the longer distance A is, the lower thespring preload. With each complete turn of the
adjusting nut, distance A is changed by 1.5 mm
(0.06 in).1. Spring preload adjusting nut
2. Locknut
3. Special wrench
(a)
(b)1 2
3
Spring preload setting:
Minimum (soft):
Distance A = 209.6 mm (8.25 in)
Standard:
Distance A = 206.0 mm (8.11 in)
Maximum (hard):
Distance A = 197.6 mm (7.78 in)1. Distance A
1
U1BT61E0.book Page 15 Tuesday, April 6, 2010 1:28 PM
Page 41 of 142
4-16
4 3. Tighten the locknut to the specified torque.
NOTICE: Always tighten the locknut
against the adjusting nut, and then tighten
it to the specified torque.
[ECB00081]
Rebound damping force
Turn the rebound damping force adjusting screw in
direction (a) to increase the rebound damping
force and thereby harden the damping, and in di-
rection (b) to decrease the rebound damping force
and thereby soften the damping.Tightening torque:
Locknut:
42 Nm (4.2 m·kgf, 30 ft·lbf)
1. Rebound damping force adjusting screwRebound damping setting:
Minimum (soft):
20 click(s) in direction (b)*
Standard:
12 click(s) in direction (b)*
Maximum (hard):
3 click(s) in direction (b)*
* With the adjusting screw fully turned in di-
rection (a)
(a) (b) 1
U1BT61E0.book Page 16 Tuesday, April 6, 2010 1:28 PM
Page 44 of 142

4-19
4
NOTICEECB01090Never turn the adjusting mechanism beyond
the minimum and maximum settings.Adjust the spring preload as follows.
1. Loosen the locknut.
2. Turn the spring preload adjusting nut in direc-
tion (a) to increase the spring preload and
thereby harden the suspension, and in direc-
tion (b) to decrease the spring preload and
thereby soften the suspension.
TIPA special wrench can be obtained at a Yamaha
dealer to make this adjustment.The spring preload setting is determined by
measuring distance A, shown in the illustration.
The shorter distance A is, the higher the spring
preload; the longer distance A is, the lower the
spring preload. With each complete turn of the
adjusting nut, distance A is changed by 1.0 mm
(0.04 in).3. Tighten the locknut to the specified torque.
NOTICE: Always tighten the locknut
against the adjusting nut, and then tighten
it to the specified torque.
[ECB00081]
1. Locknut
2. Spring preload adjusting nut
3. Distance A
2
1
(b) 3(a)
Spring preload setting:
Minimum (soft):
Distance A = 234.0 mm (9.21 in)
Standard:
Distance A = 230.0 mm (9.06 in)
Maximum (hard):
Distance A = 222.0 mm (8.74 in)
U1BT61E0.book Page 19 Tuesday, April 6, 2010 1:28 PM
Page 45 of 142

4-20
4
WARNING
EWB00450This shock absorber assembly contains highly
pressurized nitrogen gas. If the shock absorb-
er assembly is damaged, it could explode
causing injury or property damage. Shock ab-
sorber cylinder damage could also result in
poor handling which could cause an accident.Do not tamper with or attempt to open the
cylinder assembly.Do not subject the shock absorber assembly
to an open flame or other high heat.Do not deform or damage the cylinder in any
way.Do not dispose of a damaged or worn out
shock absorber assembly yourself. Take the
shock absorber assembly to a Yamaha deal-
er for any service.
EBU29312Adjusting the rear shock absorber as-
sembly (YFM25RSEA/YFM250RSEA)The spring preload, rebound damping and com-
pression damping forces of the rear shock absorb-
er assembly can be adjusted to suit the rider’s
weight and the riding conditions.
WARNING
EWB02500Suspension components become hot during
operation. Never touch the compression
damping force adjusting screw, the rebound
damping force adjusting dial or the oil reser-
voir with your bare hand or skin until suspen-
sion components have cooled.NOTICEECB00090Never turn an adjusting mechanism beyond
the minimum and maximum settings.Spring preload
1. Loosen the locknut. Tightening torque:
Locknut:
42 Nm (4.2 m·kgf, 30 ft·lbf)
U1BT61E0.book Page 20 Tuesday, April 6, 2010 1:28 PM
Page 46 of 142
4-21
42. Turn the spring preload adjusting nut in direc-
tion (a) to increase the spring preload and
thereby harden the suspension, and in direc-
tion (b) to decrease the spring preload and
thereby soften the suspension.
TIPA special wrench can be obtained at a Yamaha
dealer to make this adjustment.The spring preload setting is determined by
measuring distance A, shown in the illustration.
The shorter distance A is, the higher the spring
preload; the longer distance A is, the lower thespring preload. With each complete turn of the
adjusting nut, distance A is changed by 1.5 mm
(0.06 in).1. Locknut
2. Spring preload adjusting nut
12
(a)
(b)
Spring preload setting:
Minimum (soft):
Distance A = 232.0 mm (9.13 in)
Standard:
Distance A = 228.0 mm (8.98 in)
Maximum (hard):
Distance A = 220.0 mm (8.66 in)1. Distance A
1
U1BT61E0.book Page 21 Tuesday, April 6, 2010 1:28 PM
Page 47 of 142
4-22
4 3. Tighten the locknut to the specified torque.
NOTICE: Always tighten the locknut
against the adjusting nut, and then tighten
it to the specified torque.
[ECB00081]
Rebound damping force
Turn the rebound damping force adjusting dial in
direction (a) to increase the rebound damping
force and thereby harden the damping, and in di-
rection (b) to decrease the rebound damping force
and thereby soften the damping.Tightening torque:
Locknut:
42 Nm (4.2 m·kgf, 30 ft·lbf)
1. Rebound damping force adjusting dialRebound damping setting:
Minimum (soft):
20 click(s) in direction (b)*
Standard:
12 click(s) in direction (b)*
Maximum (hard):
3 click(s) in direction (b)*
* With the adjusting dial fully turned in direc-
tion (a)
1
(a)
(b)
U1BT61E0.book Page 22 Tuesday, April 6, 2010 1:28 PM
Page 60 of 142

6-5
6There is never a more important period in the life of
your engine than the first 320 km (200 mi) or 20
hours of riding. For this reason, you should read
the following material carefully.
Since the engine is brand new, do not put an ex-
cessive load on it for the first 320 km (200 mi) or 20
hours. The various parts in the engine wear and
polish themselves to the correct operating clear-
ances. During this period, prolonged full-throttle
operation or any condition that might result in en-
gine overheating must be avoided.
0–160 km (0–100 mi) or 0–10 hours
Avoid prolonged operation above 1/2 throttle. Vary
the speed of the ATV regularly. Do not operate it at
one set throttle position.
160–320 km (100–200 mi) or 10–20 hours
Avoid prolonged operation above 3/4 throttle. Rev
the engine through the gears freely, but do not use
full throttle at any time.
320 km (200 mi) or 20 hours and beyond
The ATV can now be operated normally.
NOTICEECB00220If any engine trouble should occur during the
engine break-in period, immediately have a
Yamaha dealer check the ATV.EBU20722Parking When parking the ATV, shift into first gear, stop the
engine, apply the parking brake, and then turn the
fuel cock to “OFF”.1. Parking brake lever (locked position)
U1BT61E0.book Page 5 Tuesday, April 6, 2010 1:28 PM