2008 YAMAHA YZ250F fuel cap

FOREWARD
INTRODUCTION
Congratulations on your purchase of
a Yamaha YZ series. This model is
the culmination of Yamaha's vast ex-
perience in the production of paceset-
ting racing machines. It represents
the highest grade of craftsmanship
and reliability that have made Yama-
ha a leader.
This manual explains operation, in-
spection, basic maintenance and tun-
ing of your machine. If you have any
questions about this manual or your
machine, please contact your Yama-
ha dealer.
Yamaha continually seeks advance-
ments in product design and quality.
Therefore, while this manual contains
the most current product information
available at the time of printing, there
may be minor discrepancies between
your machine and this manual. If you
have any questions concerning this
manual, please consult your Yamaha
dealer.
PLEASE READ THIS MANUAL
CAREFULLY AND COMPLETELY
BEFORE OPERATING THIS MA-
CHINE. DO NOT ATTEMPT TO OP-
ERATE THIS MACHINE UNTIL YOU
HAVE ATTAINED A SATISFACTO-
RY KNOWLEDGE OF ITS CON-
TROLS AND OPERATING
FEATURES AND UNTIL YOU HAVE
BEEN TRAINED IN SAFE AND
PROPER RIDING TECHNIQUES.
REGULAR INSPECTIONS AND
CAREFUL MAINTENANCE,
ALONG WITH GOOD RIDING
SKILLS, WILL ENSURE THAT YOU
SAFETY ENJOY THE CAPABILI-
TIES AND THE RELIABILITY OF
THIS MACHINE.
PARTICULARLY IMPORTANT
INFORMATION
The Safety Alert Symbol means AT-
TENTION! BECOME ALERT! YOUR
SAFETY IS INVOLVED!
Failure to follow WARNING instruc-
tions could result in severe injury or
death to the machine operator, a by-
stander, or a person inspecting or re-
pairing the machine. A CAUTION indicates special pre-
cautions that must be taken to avoid
damage to the machine.
A NOTE provides key information to
make procedures easier or clearer.
IMPORTANT NOTICE
THIS MACHINE IS DESIGNED
STRICTLY FOR COMPETITION
USE, ONLY ON A CLOSED
COURSE. It is illegal for this machine
to be operated on any public street,
road, or highway. Off-road use on
public lands may be illegal. Please
check local regulations before riding.
1. THIS MACHINE IS TO BE OP-
ERATED BY AN EXPERI-
ENCED RIDER ONLY.
Do not attempt to operate this
machine at maximum power
until you are totally familiar
with its characteristics.
2. THIS MACHINE IS DESIGNED TO BE RIDDEN BY THE OP-
ERATOR ONLY.
Do not carry passengers on
this machine.
3. ALWAYS WEAR PROTEC- TIVE APPAREL.
When operating this ma-
chine, always wear an ap-
proved helmet with goggles
or a face shield. Also wear
heavy boots, gloves, and pro-
tective clothing. Always wear
proper fitting clothing that
will not be caught in any of
the moving parts or controls
of the machine.
4. ALWAYS MAINTAIN YOUR MACHINE IN PROPER
WORKING ORDER.
For safety and reliability, the
machine must be properly
maintained. Always perform
the pre-operation checks in-
dicated in this manual. Cor-
recting a mechanical problem
before you ride may prevent
an accident.
5. GASOLINE IS HIGHLY FLAM-MABLE.
Always turn off the engine
while refueling. Take care to
not spill any gasoline on the
engine or exhaust system.
Never refuel in the vicinity of
an open flame, or while
smoking.
6. GASOLINE CAN CAUSE IN- JURY.
If you should swallow some
gasoline, inhale excess gaso-
line vapors, or allow any gas-
oline to get into your eyes,
contact a doctor immediately.
If any gasoline spills onto
your skin or clothing, imme-
diately wash skin areas with
soap and water, and change
your clothes.
7. ONLY OPERATE THE MA- CHINE IN AN AREA WITH AD-
EQUATE VENTILATION.
Never start the engine or let it
run for any length of time in
an enclosed area. Exhaust
fumes are poisonous. These
fumes contain carbon mon-
oxide, which by itself is odor-
less and colorless. Carbon
monoxide is a dangerous gas
which can cause uncon-
sciousness or can be lethal.
8. PARK THE MACHINE CARE- FULLY; TURN OFF THE EN-
GINE.
Always turn off the engine if
you are going to leave the
machine. Do not park the ma-
chine on a slope or soft
ground as it may fall over.
9. THE ENGINE, EXHAUST PIPE, MUFFLER, AND OIL
TANK WILL BE VERY HOT
AFTER THE ENGINE HAS
BEEN RUN.
Be careful not to touch them
or to allow any clothing item
to contact them during in-
spection or repair.

1-1
DESCRIPTION
GENERAL INFORMATION
DESCRIPTION
• The machine you have purchased may differ slightly from those shown in the following.
• Designs and specifications are subject to change without notice.
1. Clutch lever
2. Hot starter lever
3. Front brake lever
4. Throttle grip
5. Radiator cap
6. Fuel tank cap
7. Engine stop switch
8. Kickstarter crank
9. Fuel tank
10. Radiator
11. Coolant drain bolt
12. Rear brake pedal
13. Valve joint14. Fuel cock
15. Cold starter knob
16. Drive chain
17. Air filter
18. Oil level check window
19. Shift pedal
20. Front fork
1

2-1
GENERAL SPECIFICATIONS
SPECIFICATIONS
GENERAL SPECIFICATIONS
Model name:YZ250FX (USA, CDN, AUS, NZ)
YZ250F (EUROPE, ZA)
Model code number: 5XCL (USA,CDN)
5XCM (EUROPE)
5XCP (AUS, NZ, ZA)
Dimensions: USA, CDN, ZA, AUS, NZEUROPE
Overall length 2,162 mm (85.12 in) 2,165 mm (85.24 in)
Overall width 825 mm (32.48 in)
←
Overall height1,300 mm (51.18 in)←
Seat height 985 mm (38.78 in)997 mm (39.25 in)
Wheelbase 1,469 mm (57.83 in)
←
Minimum ground clearance370 mm (14.57 in)372 mm (14.65 in)
Dry weight: Without oil and fuel 92.7 kg (204 lb)
Engine: Engine type Liquid cooled 4-stroke, DOHC
Cylinder arrangement Single cylinder, forward inclined
Displacement 249 cm
3 (8.76 Imp oz, 8.42 US oz)
Bore × stroke 77.0 × 53.6 mm (3.03 × 2.11 in)
Compression ratio 13.5 : 1
Starting system Kickstarter
Lubrication system: Dry sump
Oil type or grade: Engine oil (For USA and CDN)
Yamalube 4, SAE10W30 or SAE20W40
Yamalube 4-R, SAE10W50
API service SG type or higher,
JASO standard MA
(Except for USA and CDN)
SAE10W30, SAE10W40, SAE15W40,
SAE20W40 or SAE20W50
API service SG type or higher,
JASO standard MA
Oil capacity: Engine oilPeriodic oil change 1.05 L (0.92 Imp qt, 1.11 US qt)
With oil filter replacement 1.15 L (1.01 Imp qt, 1.22 US qt)
Total amount 1.30 L (1.14 Imp qt, 1.37 US qt)
Coolant capacity (including all routes): 0.99 L (0.87 Imp qt, 1.05 US qt)
Air filter: Wet type element
2

2-2
GENERAL SPECIFICATIONS
Fuel:Type Premium unleaded gasoline only with a research octane
number of 95 or higher.
Tank capacity 7.0 L (1.54 Imp gal, 1.85 US gal)
Carburetor: Type FCR-MX37
Manufacturer KEIHIN
Spark plug: Type/manufacturer CR8E/NGK (resistance type)
Gap 0.7–0.8 mm (0.028–0.031 in)
Clutch type: Wet, multiple-disc
Transmission: Primary reduction system Gear
Primary reduction ratio 57/17 (3.353)
Secondary reduction system Chain drive
Secondary reduction ratio 49/13 (3.769)
Transmission type Constant mesh, 5-speed
Operation Left foot operation
Gear ratio: 1st 30/14 (2.143)
2nd 28/16 (1.750)
3rd 29/20 (1.450)
4th 27/22 (1.227)
5th 25/24 (1.042)
Chassis: USA, CDN, AUS, NZ, ZAEUROPE
Frame type Semi double cradle
←
Caster angle27.1°26.9°
Trail 116.9 mm (4.60 in) 115.1 mm (4.53 in)
Tire: Type With tube
Size (front) 80/100-21 51M
Size (rear) 100/90-19 57M
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm
2, 15 psi)
Brake: Front brake type Single disc brake
Operation Right hand operation
Rear brake type Single disc brake
Operation Right foot operation
Suspension: Front suspension Telescopic fork
Rear suspension Swingarm (link type monocross suspension)
Shock absorber: Front shock absorber Coil spring/oil damper
Rear shock absorber Coil spring/gas, oil damper
Wheel travel: Front wheel travel 300 mm (11.8 in)

3-5
PRE-OPERATION INSPECTION AND MAINTENANCE
PRE-OPERATION INSPECTION AND MAINTENANCE
Before riding for break-in operation, practice or a race, make sure the machine is in good operating condition.
Before using this machine, check the following points.
GENERAL INSPECTION AND MAINTENANCEItem RoutinePage
Coolant Check that coolant is filled up to the radiator cap. Check the cool-
ing system for leakage. P.3-6 – 7
Fuel Check that a fresh gasoline is filled in the fuel tank. Check the fuel
line for leakage. P.1-8 – 9
Engine oil Check that the oil level is correct. Check the crankcase and oil line
for leakage. P.3-8 – 10
Gear shifter and clutch Check that gears can be shifted correctly in order and that the
clutch operates smoothly. P.3-7
Throttle grip/Housing Check that the throttle grip operation and free play are correctly
adjusted. Lubricate the throttle grip and housing, if necessary. P.3-7 – 8
Brakes Check the play of front brake and effect of front and rear brake. P.3-14 – 16
Drive chain Check drive chain slack and alignment. Check that the drive chain
is lubricated properly. P.3-17
Wheels Check for excessive wear and tire pressure. Check for loose
spokes and have no excessive play. P.3-20
Steering Check that the handlebar can be turned smoothly and have no ex-
cessive play. P.3-20 – 21
Front forks and rear shock
absorber Check that they operate smoothly and there is no oil leakage.
P.3-18 – 20
Cables (wires) Check that the clutch and throttle cables move smoothly. Check
that they are not caught when the handlebars are turned or when
the front forks travel up and down.
—
Exhaust pipe Check that the exhaust pipe is tightly mounted and has no cracks. P.4-3 – 4
Rear wheel sprocket Check that the rear wheel sprocket tightening bolt is not loose. P.3-16 – 17
Lubrication Check for smooth operation. Lubricate if necessary. P.3-22
Bolts and nuts Check the chassis and engine for loose bolts and nuts. P.1-11
Lead connectors Check that the CDI magneto, CDI unit, and ignition coil are con-
nected tightly. P.1-3
Settings Is the machine set suitably for the condition of the racing course
and weather or by taking into account the results of test runs be-
fore racing? Are inspection and maintenance completely done?
P.7-1 – 10

3-10
ENGINE
• Oil hose clamp
9. Install: • Copper washer
• Oil filter element drain bolt
• Crankcase oil drain bolt
• Oil tank drain bolt
• Lower engine guard
10. Fill: • Engine oil
11. Check: • Oil leakage
12. Install: • Oil filler cap
• Washer (oil tank) • Bolt (oil tank)
13. Check: • Engine oil level
CHECKING THE OIL PRESSURE
1. Check: • Oil pressure
Checking steps:
a. Slightly loosen the oil pressure check bolt "1".
b. Start the engine and keep it idling until oil starts to seep from the oil
pressure check bolt. If no oil
comes out after one minute, turn
the engine off so it will not seize.
c. Check oil passages and oil pump for damage or leakage.
d. Start the engine after solving the
problem(s) and recheck the oil
pressure.
e. Tighten the oil pressure check
bolt.
ADJUSTING THE PILOT SCREW
1. Adjust:• Pilot screw "1"
Adjustment steps:
To optimize the fuel flow at a smaller
throttle opening, each machine's pilot
screw has been individually set at the
factory. Before adjusting the pilot
screw, turn it in fully and count the
number of turns. Record this number
as the factory-set number of turns
out.
a. Turn in the pilot screw until it is lightly seated.
b. Turn out the pilot screw by the factory-set number of turns.
ADJUSTING THE ENGINE IDLING
SPEED
1. Start the engine and thoroughly warm it up.
2. Adjust: • Engine idling speed
Adjustment steps:
a. Adjust the pilot screw. Refer to "ADJUSTING THE PI-
LOT SCREW" section.
b. Turn the throttle stop screw "1"
until the specified engine idling
speed.
Using a digital engine tachometer for
idle speed adjustment, detect the en-
gine idling speed by bringing the
sensing element "c" of the engine ta-
chometer close to the ignition coil "2".
Oil hose clamp:2 Nm (0.2 m•kg, 1.4
ft•lb)
Oil filter element drain
bolt: 10 Nm (1.0 m•kg, 7.2
ft•lb)
Crankcase oil drain bolt: 20 Nm (2.0 m•kg, 14
ft•lb)
Oil tank drain bolt: 18 Nm (1.8 m•kg, 13
ft•lb)
Lower engine guard: 10 Nm (1.0 m•kg, 7.2
ft•lb)
Oil quantity: Periodic oil change:1.05 L (0.92 Imp qt,
1.11 US qt)
With oil filter replace-
ment: 1.15 L (1.01 Imp qt,
1.22 US qt)
Total amount:
1.30 L (1.14 Imp qt,
1.37 US qt)Bolt (oil tank): 7 Nm (0.7 m•kg, 5.1
ft•lb)
Oil pressure check bolt: 10 Nm (1.0 m•kg, 7.2
ft•lb)
Pilot screw (example): 2-3/8 turns out
To increase idle speed→Turn the
throttle stop screw "1" in "a".
To decrease idle speed
→Turn
the throttle stop screw "1" out
"b".
Engine idling speed:1,900–2,100 r/min