2009 YAMAHA YFM250R-W compression ratio

4-20
4
NOTICEECB00090Never turn an adjusting mechanism beyondthe minimum and maximum settings.TIPAlthough the total number of clicks of a damping
force adjusting mechanism may not exactly match
the above specifications due to small differences in
production, the actual number of clicks always rep-
resents the entire adjusting range. To obtain a pre-
cise adjustment, it would be advisable to check the
number of clicks of each damping force adjusting
mechanism and to modify the specifications asnecessary.
WARNING
EWB02490
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 anaccident.EBU28240Adjusting the rear shock absorber as-
sembly (YFM250R-W)The spring preload can be adjusted to suit the rid-
er’s weight and the riding conditions.
Adjust the spring preload as follows.
1. Loosen the locknut.
2. Turn the adjusting nut in direction (a) to in-
crease the spring preload and thereby harden
the suspension, and in direction (b) to de-
crease the spring preload and thereby soften
the suspension.
U33B70E0.book Page 20 Wednesday, June 11, 2008 1:38 PM

4-26
4
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.U33B70E0.book Page 26 Wednesday, June 11, 2008 1:38 PM

8-43
8
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.U33B70E0.book Page 43 Wednesday, June 11, 2008 1:38 PM

10-1
10
EBU25960
SPECIFICATIONS
Dimensions:Overall length:
1650 mm (65.0 in)
Overall width:
1080 mm (42.5 in)
Overall height:
1100 mm (43.3 in)
Seat height:
730 mm (28.7 in)
Wheelbase:
1110 mm (43.7 in)
Ground clearance:
110 mm (4.3 in)
Minimum turning radius:
2900 mm (114 in)Weight:With oil and fuel:
160.0 kg (353 lb)Engine:Engine type:
Air cooled 4-stroke, SOHC
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
249.0 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 sump
Engine oil:Type:
SAE 5W-30 or SAE 10W-30 or SAE 10W-40 or SAE
15W-40 or SAE 20W-40 or SAE 20W-50
Recommended engine oil grade:
API service SG type or higher, JASO standard MA-20 -10 0
1020 304050 ˚C
SAE 15W-40
SAE 20W-40SAE 20W-50
SAE 10W-40
SAE 5W-30
SAE 10W-30
U33B70E0.book Page 1 Wednesday, June 11, 2008 1:38 PM