engine YAMAHA YZ250F 2004 Owner's Manual

1 - 20
GEN
INFO

CLEANING AND STORAGE
EC1B2001
STORAGE
If your machine is to be stored for 60 days or
more, some preventive measures must be
taken to avoid deterioration. After cleaning the
machine thoroughly, prepare it for storage as
follows:
1. Drain the fuel tank, fuel lines, and the
carburetor float bowl.
2. Remove the spark plug, pour a table-
spoon of SAE 10W-30 motor oil in the
spark plug hole, and reinstall the plug.
With the engine stop switch pushed in,
kick the engine over several times to coat
the cylinder walls with oil.
3. Remove the drive chain, clean it thor-
oughly with solvent, and lubricate it.
Reinstall the chain or store it in a plastic
bag tied to the frame.
4. Lubricate all control cables.
5. Block the frame up to raise the wheels off
the ground.
6. Tie a plastic bag over the exhaust pipe
outlet to prevent moisture from entering.
7. If the machine is to be stored in a humid
or salt-air environment, coat all exposed
metal surfaces with a film of light oil. Do
not apply oil to rubber parts or the seat
cover.
NOTE:

Make any necessary repairs before the
machine is stored.

SPEC

2 - 1
GENERAL SPECIFICATIONS
EC200000
SPECIFICATIONS
EC211000
GENERAL SPECIFICATIONS
Model name: YZ250FS (USA)
YZ250F (EUROPE)
YZ250F(S) (CDN, AUS, NZ, ZA)
Model code number: 5XC1 (USA)
5XC2 (EUROPE)
5XC4 (CDN, AUS, NZ, ZA)
Dimensions:
Overall length 2,165 mm (85.2 in)
Overall width 827 mm (32.6 in)
Overall height 1,303 mm (51.3 in)
Seat height 995 mm (39.2 in)
Wheelbase 1,475 mm (58.1 in)
Minimum ground clearance 382 mm (15.0 in)
Dry weight:
Without oil and fuel 93.5 kg (206 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 12.5 : 1
Starting system Kickstarter
Lubrication system: Dry sump
Oil type or grade:
Engine oil (For USA and CDN)
At 5 ˚C (40 ˚F) or higher
Å
Yamalube 4 (20W-40) or SAE 20W-40 type
SG motor oil
(Non-Friction modified)
At 15 ˚C (60 ˚F) or lower
ı

Yamalube 4 (10W-30) or SAE 10W-30 type
SG motor oil
(Non-Friction modified)
and/or
Yamalube 4-R (15W-50)
(Non-Friction modified)
(Except for USA and CDN)
API “SG” or higher grade
-20
-4-10
140
3010
5020
6830
8640 50
104
122°CTemp.
°F
10W-30
10W-40
20W-40
20W-50
15W-40

2

SPEC

2 - 2
GENERAL SPECIFICATIONS
Oil capacity:
Engine oil
Periodic oil change 1.0 L (0.88 Imp qt, 1.06 US qt)
With oil filter replacement 1.1 L (0.97 Imp qt, 1.16 US qt)
Total amount 1.2 L (1.06 Imp qt, 1.27 US qt)
Coolant capacity (including all routes): 0.9 L (0.79 Imp qt, 0.95 US qt)
Air filter: Wet type element
Fuel:
Type Premium unleaded gasoline only with a
research octane number of 95 or higher.
(Except for ZA)
Premium gasoline (For ZA)
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 48/13 (3.692) (Except for EUROPE)
49/13 (3.769) (For EUROPE)
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:
Frame type Semi double cradle
Caster angle 27.1˚
Trail 117.4 mm (4.62 in)
Tire:
Type With tube
Size (front) 80/100-21 51M (For USA, CDN, ZA, AUS, NZ
and F)
80/100-21 51R (For EUROPE except F)
Size (rear) 100/90-19 57M (For USA, CDN, ZA, AUS, NZ
and F)
100/90-19 NHS (For EUROPE except F)
Tire pressure (front and rear) 100 kPa (1.0 kgf/cm
2

, 15 psi)
1
2

SPEC

2 - 4
MAINTENANCE SPECIFICATIONS
MAINTENANCE SPECIFICATIONS
ENGINE
Item Standard Limit
Cylinder head:
Warp limit ---- 0.05 mm
(0.002 in)
Cylinder:
Bore size 77.00 ~ 77.01 mm
(3.0315 ~ 3.0319 in)----
Out of round limit ---- 0.05 mm
(0.002 in)
Camshaft:
Drive method Chain drive (Left) ----
Camshaft cap inside diameter 22.000 ~ 22.021 mm
(0.8661 ~ 0.8670 in)----
Camshaft outside diameter 21.967 ~ 21.980 mm
(0.8648 ~ 0.8654 in)----
Shaft-to-cap clearance 0.020 ~ 0.054 mm
(0.0008 ~ 0.0021 in)0.08 mm
(0.003 in)
Cam dimensions
Intake“A”30.296 ~ 30.346 mm
(1.1923 ~ 1.1947 in)30.196 mm
(1.1888 in)
“B”22.45 ~ 22.55 mm
(0.8839 ~ 0.8878 in)22.35 mm
(0.8799 in)
Exhaust“A”30.399 ~ 30.499 mm
(1.1968 ~ 1.2007 in)30.299 mm
(1.1929 in)
“B”22.45 ~ 22.55 mm
(0.8839 ~ 0.8878 in)22.35 mm
(0.8799 in)
Camshaft runout limit ---- 0.03 mm
(0.0012 in)
A
B

SPEC

2 - 8
MAINTENANCE SPECIFICATIONS
Clutch:
Friction plate thickness 2.9 ~ 3.1 mm
(0.114 ~ 0.122 in)2.7 mm
(0.106 in)
Quantity 9 ----
Clutch plate thickness 1.1 ~ 1.3 mm (0.043 ~ 0.051 in) ----
Quantity 8 ----
Warp limit ---- 0.1 mm
(0.004 in)
Clutch spring free length 40.4 mm (1.59 in) 39.4 mm
(1.55 in)
Quantity 5 ----
Clutch housing thrust clearance 0.10 ~ 0.35 mm
(0.0039 ~ 0.0138 in)----
Clutch housing radial clearance 0.010 ~ 0.044 mm
(0.0004 ~ 0.0017 in)----
Clutch release method Inner push, cam push ----
Shifter:
Shifter type Cam drum and guide bar ----
Guide bar bending limit ---- 0.05 mm
(0.002 in)
Kickstarter:
Type Kick and ratchet type ----
Carburetor:
Type/manufacturer FCR-MX37/KEIHIN ----
I. D. mark 5XC1 00 ----
Main jet (M.J) #180 ----
Main air jet (M.A.J)ø2.0 ----
Jet needle (J.N) OBEKR-4 ----
Cutaway (C.A) 1.5 ----
Pilot jet (P.J) #42 ----
Pilot air jet (P.A.J) #100 ----
Pilot outlet (P.O)ø0.9 ----
Pilot screw (example) (P.S) 1-5/8 ----
Bypass (B.P)ø1.0 ----
Valve seat size (V.S)ø3.8 ----
Starter jet (G.S) #72 ----
Leak jet (Acc.P) #90 ----
Float height (F.H) 8 mm (0.31 in) ----
Engine idle speed 1,900 ~ 2,100 r/min ----
Intake vacuum26.7 ~ 32.0 kPa
(200 ~ 240 mmHg, 7.87 ~ 9.45 inHg)----
Hot starter lever free play 3 ~ 6 mm (0.12 ~ 0.24 in) ----Item Standard Limit

SPEC
2 - 15
MAINTENANCE SPECIFICATIONS
NOTE:
- marked portion shall be checked for torque tightening after break-in or before each race.Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Nipple (spoke)—72 3 0.3 2.2
Rear wheel sprocket M8 × 1.25 6 42 4.2 30
Rear brake disc cover M6 × 1.0 2 7 0.7 5.1
Rear brake caliper protector M6 × 1.0 2 7 0.7 5.1
Drive chain puller adjust bolt and locknut M8 × 1.25 2 16 1.6 11
Engine mounting:
Engine and engine bracket (front) M10 × 1.25 1 69 6.9 50
Engine and frame (lower) M10 × 1.25 1 69 6.9 50
Upper engine bracket and frame M8 × 1.25 2 44 4.4 32
Lower engine bracket and frame M8 × 1.25 4 34 3.4 24
Engine and engine bracket (upper) M10 × 1.25 1 55 5.5 40
Lower engine guard M6 × 1.0 3 10 1.0 7.2
Right engine guard M8 × 1.25 2 23 2.3 17
CDI unit bracket M6 × 1.0 1 10 1.0 7.2
Pivot shaft and nut M16 × 1.5 1 85 8.5 61
Relay arm and swingarm M14 × 1.5 1 80 8.0 58
Relay arm and connecting rod M14 × 1.5 1 80 8.0 58
Connecting rod and frame M14 × 1.5 1 80 8.0 58
Rear shock absorber and frame M10 × 1.25 1 56 5.6 40
Rear shock absorber and relay arm M10 × 1.25 1 53 5.3 38
Rear frame (upper) M8 × 1.25 1 32 3.2 23
Rear frame (lower) M8 × 1.25 2 29 2.9 21
Swingarm and brake hose holder M5 × 0.8 4 1 0.1 0.7
Swingarm and patch M4 × 0.7 4 2 0.2 1.4
Upper drive chain tensioner M8 × 1.25 1 19 1.9 13
Lower drive chain tensioner M8 × 1.25 1 20 2.0 14
Drive chain support M6 × 1.0 3 7 0.7 5.1
Seal guard and swingarm M5 × 0.8 4 6 0.6 4.3
Fuel tank M6 × 1.0 2 10 1.0 7.2
Fuel cock M6 × 1.0 2 7 0.7 5.1
Seat set bracket and fuel tank M6 × 1.0 1 7 0.7 5.1
Hooking screw (fitting band) and fuel tank M6 × 1.0 1 7 0.7 5.1
Fuel tank bracket and fuel tank M6 × 1.0 4 7 0.7 5.1
Air scoop and fuel tank M6 × 1.0 6 6 0.6 4.3
Air scoop and radiator guard (lower) M6 × 1.0 2 6 0.6 4.3
Front fender M6 × 1.0 4 7 0.7 5.1
Rear fender (front) M6 × 1.0 2 7 0.7 5.1
Rear fender (rear) M6 × 1.0 2 12 1.2 8.7
Side cover M6 × 1.0 2 7 0.7 5.1
Seat M8 × 1.25 2 23 2.3 17
Number plate M6 × 1.0 1 7 0.7 5.1

SPEC
2 - 17
EC220001
GENERAL TORQUE SPECIFICATIONS
This chart specifies torque for standard fasten-
ers with standard I.S.O. pitch threads. Torque
specifications for special components or
assemblies are included in the applicable sec-
tions of this book. To avoid warpage, tighten
multi-fastener assemblies in a crisscross fash-
ion, in progressive stages, until full torque is
reached. Unless otherwise specified, torque
specifications call for clean, dry threads. Com-
ponents should be at room temperature.
A: Distance between flats
B: Outside thread diameter
EC230000
DEFINITION OF UNITS
A
(Nut)B
(Bolt)TORQUE
SPECIFICATION
Nm m•kg ft•lb
10 mm
12 mm
14 mm
17 mm
19 mm
22 mm6 mm
8 mm
10 mm
12 mm
14 mm
16 mm6
15
30
55
85
1300.6
1.5
3.0
5.5
8.5
134.3
11
22
40
61
94
Unit Read Definition Measure
mm
cmmillimeter
centimeter10
-3 meter
10-2 meterLength
Length
kg kilogram 10
3 gram Weight
N Newton 1 kg × m/sec
2 Force
Nm
m • kgNewton meter
Meter kilogramN × m
m × kgTorque
Torque
Pa Pascal N/m
2Pressure
N/mm Newton per millimeter N/mm Spring rate
L
cm
3 Liter
Cubic centimeter—
—Volume or capacity
Volume or capacity
r/min Revolution per minute—Engine speed
GENERAL TORQUE SPECIFICATIONS/
DEFINITION OF UNITS

2 - 18
SPEC

CABLE ROUTING DIAGRAM
EC240000
CABLE ROUTING DIAGRAM
1
Fuel tank breather hose
2
Clutch cable
3
Oil tank breather hose
4
Hot starter cable
5
Cylinder head breather hose
6
Cable guide
7
Hose guide
8
Brake hose
9
Engine stop switch lead
0
Clamp
A
Sub-wire harness
B
Throttle position sensor lead
C
Neutral switch lead
D
Oil hose
E
CDI magneto lead
F
Radiator breather hose
G
Carburetor breather hose
H
Carburetor overflow hose
Å
Insert the end of the fuel tank
breather hose into the hole in
the steering stem cap.
ı
Pass the hot starter cable
between the cylinder head
breather hose, oil tank breather
hose and ignition coil, then on
the outside of the left engine
bracket.
Ç
Pass the clutch cable through
the cable guides.
Î
Pass the clutch cable in front of
the radiator mounting boss.
‰
Fit the brake hose into the
guides on the protector.
Ï
Fasten the neutral switch lead
and CDI magneto lead to the
cable guide with a plastic locking
tie and cut off the tie end.
Ì
Fasten the engine stop switch
lead, neutral switch lead and
CDI magneto lead.
Ó
Fasten the engine stop switch
lead and sub-wire harness at the
protecting tube for the engine
stop switch lead.
È
Fasten the sub-wire harness
and hot starter cable at the white
tape for the sub-wire harness.
Ô
Fasten the sub-wire harness.

Pass the sub-wire harness
between the engine brackets.
A
C-C
B
CC
A
D
F
C
1
2
3
4
5 6 6 78
G
H
G0
0DCB0 0 0
A 9
0
0
B
0 Ï
Ì
Ó
Ô

Ô
Ò
˜
ˆ Ø 0 E F
∏ Œ Å
ı
Ç Î Ç ‰
Â
0
È

2 - 22
SPECCABLE ROUTING DIAGRAM
1Throttle cable
2Fuel tank breather hose
3Clamp
4Clutch cable
5Hot starter cable
6Engine stop switch lead
7Brake hose
8Hose guideÅFasten the engine stop switch lead to the handlebar.
ıPass the brake hose in front of the number plate.
3
6
12
3
4
5
6
7
8ı Å
A
A

3 - 1
INSP
ADJ

MAINTENANCE INTERVALS
EC300000
REGULAR INSPECTION AND ADJUSTMENTS
MAINTENANCE INTERVALS
The following schedule is intended as a general guide to maintenance and lubrication. Bear in mind
that such factors as weather, terrain, geographical location, and individual usage will alter the
required maintenance and lubrication intervals. If you are a doubt as to what intervals to follow in
maintaining and lubricating your machine, consult your Yamaha dealer.
ItemAfter
break-inEvery
race
Every
third
(or
500 km)Every
fifth
(or
1,000 km)
As re-
quiredRemarks
ENGINE OIL
Replace
Inspect
●

●●

●
OIL FILTER ELEMENT, OIL STRAINER
Clean
●

VALVES
Check the valve clearances
Inspect
Replace
●

●

●

●
The engine must be cold.
Check the valve seats
and valve stems for wear.
VALVE SPRINGS
Inspect
Replace
●

●
Check the free length and
the tilt.
VALVE LIFTERS
Inspect
Replace
●

●
Check for scratches and
wear.
CAMSHAFTS
Inspect
Replace
●

●
Inspect the camshaft sur-
face.
Inspect the decompres-
sion system.
TIMING CHAIN SPROCKETS, TIMING
CHAIN
Inspect
Replace
●

●
Check for wear on the
teeth and for damage.
PISTON
Inspect
Clean
Replace
●

●

●

●
Inspect crack
Inspect carbon deposits
and eliminate them.
PISTON RING
Inspect
Replace
●

●

●
Check ring end gap
PISTON PIN
Inspect
Replace
●

●

CYLINDER HEAD
Inspect and clean
●
Inspect carbon deposits
and eliminate them.
Change gasket
CYLINDER
Inspect and clean
Replace
●

●
Inspect score marks
Inspect wear
CLUTCH
Inspect and adjust
Replace
●

●

●
Inspect housing, friction
plate, clutch plate and
spring
TRANSMISSION
Inspect
Replace bearing
●

●