compression ratio YAMAHA YFM250R 2011 Owners Manual

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
EWB02491
Suspension 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
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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)
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8-43
8 3. Lower the ATV to the ground.
4. Tighten the wheel nuts to the specified
torques.
EBU25720Troubleshooting Although Yamaha ATVs receive a thorough in-
spection before shipment from the factory, trouble
may occur during operation. Any problem in the fu-
el, compression, or ignition systems, for example,
can cause poor starting and loss of power.
The following troubleshooting chart represents a
quick and easy procedure for checking these vital
systems yourself. However, should your ATV re-
quire any repair, take it to a Yamaha dealer, whose
skilled technicians have the necessary tools, expe-
rience, and know-how to service the ATV properly.
Use only genuine Yamaha replacement parts. Im-
itation parts may look like Yamaha parts, but they
are often inferior, have a shorter service life and
can lead to expensive repair bills.
WARNING
EWB02280Do not smoke when checking the fuel system.
Fuel can ignite or explode, causing severe inju-
ry or property damage. Make sure there are no
open flames or sparks in the area, including pi-
lot lights from water heaters or furnaces.
1. Arrow markTightening torques:
Front wheel nut:
45 Nm (4.5 m·kgf, 33 ft·lbf)
Rear wheel nut:
45 Nm (4.5 m·kgf, 33 ft·lbf)
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10-1
10
EBU25960
SPECIFICATIONS
Dimensions:Overall length:
1625 mm (64.0 in)
Overall width:
1072 mm (42.2 in)
Overall height:
1040 mm (40.9 in)
Seat height:
730 mm (28.7 in)
Wheelbase:
1110 mm (43.7 in)
Ground clearance:
100 mm (3.9 in)
Minimum turning radius:
2900 mm (114 in)Weight:With oil and fuel:
150.0 kg (331 lb)Noise and vibration level:Noise level (77/311/EEC):
YFM25RA 81.0 dB(A)@3500 r/min
YFM25RSEA 81.0 dB(A)@3500 r/min
Noise level 40 CFR Part 205 Subpart D (Acceleration):
YFM25RA 78.8 dB(A)
YFM25RSEA 78.8 dB(A)
Vibration on seat (EN1032, ISO5008):
YFM25RA Will not exceed 0.5 m/s²
YFM25RSEA Will not exceed 0.5 m/s²Vibration on handlebar (EN1032, ISO5008):
YFM25RA Will not exceed 2.5 m/s²
YFM25RSEA Will not exceed 2.5 m/s²
Engine:Engine type:
Air cooled 4-stroke, SOHC
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
249 cm³
Bore × stroke:
74.0 × 58.0 mm (2.91 × 2.28 in)
Compression ratio:
9.50 :1
Starting system:
Electric starter
Lubrication system:
Wet sumpEngine oil:Recommended brand:
YAMALUBE
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