compression ratio YAMAHA YBR250 2011 Owners Manual

PERIODIC MAINTENANCE AND ADJUSTMENT
6-33
6
EAU25851
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 chart
represents a quick and easy procedure
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.
WARNING
EWA15141
When checking the fuel system, do
not smoke, and make sure there are
no open flames or sparks in the ar-
ea, including pilot lights from waterheaters or furnaces. Gasoline or
gasoline vapors can ignite or ex-
plode, causing severe injury or
property damage.
U5D1E1E0.book Page 33 Friday, September 5, 2008 1:17 PM

SPECIFICATIONS
8-1
8
Dimensions:Overall length:
2025 mm (79.7 in)
Overall width:
745 mm (29.3 in)
Overall height:
1065 mm (41.9 in)
Seat height:
805 mm (31.7 in)
Wheelbase:
1360 mm (53.5 in)
Ground clearance:
190 mm (7.48 in)
Minimum turning radius:
2395 mm (94.3 in)Weight:With oil and fuel:
154.0 kg (340 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:
9.80 :1
Starting system:
Electric starter
Lubrication system:
Wet sump
Engine oil:Type:
SAE 20W-40 or 20W-50
Recommended engine oil grade:
API service SF, SG type or higher, JASO
standard MA
Engine oil quantity:
Without oil filter element replacement:
1.35 L (1.43 US qt, 1.19 Imp.qt)
With oil filter element replacement:
1.45 L (1.53 US qt, 1.28 Imp.qt)Air filter:Air filter element:
Wet elementFuel:Recommended fuel:
Regular unleaded gasoline only
Fuel tank capacity:
19.2 L (5.07 US gal, 4.22 Imp.gal)
Fuel reserve amount:
4.5 L (1.19 US gal, 0.99 Imp.gal)
Fuel injection:Throttle body:
Type/quantity:
33EHS-3D01/1Spark plug (s):Manufacturer/model:
NGK/DR8EA
Spark plug gap:
0.6–0.7 mm (0.024–0.028 in)Clutch:Clutch type:
Wet, multiple-discTransmission:Primary reduction system:
Spur gear
Primary reduction ratio:
74/24 (3.083)
Secondary reduction system:
Chain drive
Secondary reduction ratio:
44/15 (2.933)
Transmission type:
Constant mesh 5-speed
Operation:
Left foot operation
Gear ratio:
1st:
36/14 (2.571)
2nd:
32/19 (1.684)
3rd:
28/22 (1.273)
4th:
26/25 (1.040)
-20 -10 0
10 20 30
40
50 ˚C
SAE 10W-30
SAE 15W-40SAE 20W-40SAE 20W-50
SAE 10W-40SAE 10W-50
U5D1E1E0.book Page 1 Friday, September 5, 2008 1:17 PM