compression ratio YAMAHA WR 250X 2008 Owners Manual

INSTRUMENT AND CONTROL FUNCTIONS
3-15
2
34
5
6
7
8
9

EAU14790
Front fork bleeding
When riding in extremely rough condi-
tions, the air temperature and pressure
in the front fork will rise. This will in-
crease the spring preload and harden
the front suspension. If this occurs,
bleed the front fork as follows.
1. Elevate the front wheel by placing
a suitable stand under the engine.
NOTE:

When bleeding the front fork, there
should be no weight on the front end of
the vehicle.
2. Remove the bleed screws and al-
low all of the air to escape fromeach fork leg.
WARNING

EWA10200
Always bleed both fork legs, other-
wise poor handling and loss of sta-
bility may result.
3. Install the bleed screws.
EAU45260
Adjusting the shock absorber
assembly
This shock absorber assembly is
equipped with a spring preload adjust-
ing ring, a rebound damping force ad-
justing dial and a compression
damping force adjusting screw.
CAUTION:

ECA10100
Never attempt to turn an adjusting
mechanism beyond the maximum or
minimum settings.
Spring preload
Spring preload adjustment should be
made by a Yamaha dealer, since this
service requires special tools and tech-
nical skills. The specified settings are
listed below.
NOTE:

The spring preload setting is deter-
mined by measuring distance A, shown
in the illustration. The shorter the dis-
tance A is, the higher the spring pre-
load; the longer distance A is, the lower
the spring preload.
1. Bleed screw
1

PERIODIC MAINTENANCE AND MINOR REPAIR
6-40
1
2
3
4
5
6
7
8
9

EAU25870
Troubleshooting
Although Yamaha motorcycles receive
a thorough inspection before shipment
from the factory, trouble may occur dur-
ing operation. Any problem in the fuel,
compression, or ignition systems, for
example, can cause poor starting and
loss of power.
The following troubleshooting charts
represent quick and easy procedures
for checking these vital systems your-
self. However, should your motorcycle
require any repair, take it to a Yamaha
dealer, whose skilled technicians have
the necessary tools, experience, and
know-how to service the motorcycle
properly.
Use only genuine Yamaha replace-
ment parts. Imitation parts may look like
Yamaha parts, but they are often inferi-
or, have a shorter service life and can
lead to expensive repair bills.

8-1
2
3
4
5
6
7
89

SPECIFICATIONS
EAU2633N
Dimensions:
Overall length:
2115 mm (83.3 in)
Overall width:
810 mm (31.9 in)
Overall height:
1190 mm (46.9 in)
Seat height:
895 mm (35.2 in)
Wheelbase:
1425 mm (56.1 in)
Ground clearance:
265 mm (10.43 in)
Minimum turning radius:
2300 mm (90.6 in)
Weight:
With oil and fuel:
136.0 kg (300 lb)
Engine:
Engine type:
Liquid cooled 4-stroke, DOHC
Cylinder arrangement:
Forward-inclined single cylinder
Displacement:
250.0 cm
3

Bore
×
stroke:
77.0
×
53.6 mm (3.03
×
2.11 in)
Compression ratio:
11.80 :1
Starting system:
Electric starterLubrication system:
Wet sump

Engine oil:
Type:
SAE 20W-40
Recommended engine oil grade:
API service SG type or higher, JASO stan-
dard MA
Engine oil quantity:
Without oil filter element replacement:
1.30 L (1.37 US qt) (1.14 Imp.qt)
With oil filter element replacement:
1.40 L (1.48 US qt) (1.23 Imp.qt)
Cooling system:
Coolant reservoir capacity (up to the maxi-
mum level mark):
0.25 L (0.26 US qt) (0.22 Imp.qt)
Radiator capacity (including all routes):
0.90 L (0.95 US qt) (0.79 Imp.qt)
Air filter:
Air filter element:
Wet element
Fuel:
Recommended fuel:
Premium unleaded gasoline only
Fuel tank capacity:
7.6 L (2.01 US gal) (1.67 Imp.gal)
Fuel reserve amount:
2.1 L (0.55 US gal) (0.46 Imp.gal)
Fuel injection:
Throttle body:
Manufacturer:
MIKUNI
Type/quantity:
38EIS/1
Spark plug (s):
Manufacturer/model:
NGK/CR9EK
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)
Clutch:
Clutch type:
Wet, multiple-disc
Transmission:
Primary reduction system:
Spur gear
Primary reduction ratio:
78/25 (3.120)
Secondary reduction system:
Chain drive
Secondary reduction ratio:
42/13 (3.231)
Transmission type:
Constant mesh 6-speed
-20 -10 0
10 20 30
40
50 ˚C
SAE 10W-30
SAE 15W-40SAE 20W-40SAE 20W-50
SAE 10W-40SAE 10W-50