2002 YAMAHA WR 250F engine

SPEC

2 - 2
GENERAL SPECIFICATIONS
Oil capacity:
Engine oil
Periodic oil change 1.5 L (1.32 Imp qt, 1.59 US qt)
With oil filter replacement 1.6 L (1.41 Imp qt, 1.69 US qt)
Total amount 1.7 L (1.50 Imp qt, 1.80 US qt)
Coolant capacity (including all routes): 1.3 L (1.14 Imp qt, 1.37 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 12 L (2.64 Imp gal, 3.17 US gal)
(For USA and CDN)
8.0 L (1.76 Imp gal, 2.11 US gal)
(Except for USA and CDN)
Reserve 1.6 L (0.35 Imp gal, 0.42 US gal)
(For USA and CDN)
1.4 L (0.31 Imp gal, 0.37 US gal)
(Except for USA and CDN)
Carburetor:
Type FCR-MX37
Manufacturer KEIHIN
Spark plug:
Type/manufacturer CR8E/NGK
U24ESR-N/DENSO
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 52/13 (4.000)
Transmission type Constant mesh, 5-speed
Operation Left foot operation
Gear ratio: 1st 31/13 (2.385)
2nd 28/16 (1.750)
3rd 28/21 (1.333)
4th 25/24 (1.042)
5th 22/27 (0.815)
Chassis:
Frame type Semi double cradle
Caster angle 27.1˚
Trail 117.4 mm (4.62 in)

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 37.0 mm (1.46 in) 36.0 mm
(1.42 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:
USA EUROPECDN, ZA,
AUS, NZ
Type/manufacturer FCR-MX37/
KEIHIN
←←
I. D. mark 5PH5 50 5PH6 60 5PH8 80
Main jet (M.J) #175 #172 #170
Main air jet (M.A.J) #200
←←
Jet needle (J.N) OBELQ-3 OBELN-4 OBEKP-3
Cutaway (C.A) 1.5
←←
Pilot jet (P.J) #40
←←
Pilot air jet (P.A.J) #75
←←
Pilot outlet (P.O)ø0.9
←←
Pilot screw (example) (P.S) 2 1 1-1/8
Bypass (B.P)ø1.0
←←
Valve seat size (V.S)ø3.8
←←
Starter jet (G.S) #72
←←
Leak jet (Acc.P) #60 #90 #105
Float height (F.H) 8 mm (0.31 in)
←←
Engine idle speed 1,800 ~
2,100 r/min
←←
Intake vacuum
26.7 ~ 32.0 kPa
(200 ~ 240 mmHg,
7.87 ~ 9.45 inHg)

←←
Item Standard Limit

SPEC
2 - 15
MAINTENANCE SPECIFICATIONS
Part to be tightened Thread size Q’tyTightening torque
Nm m·kg ft·lb
Rear brake disc M6 × 1.0 6 14 1.4 10
Brake pedal M8 × 1.25 1 26 2.6 19
Rear brake master cylinder M6 × 1.0 2 10 1.0 7.2
Rear brake reservoir tank M6 × 1.0 1 10 1.0 7.2
Rear brake reservoir tank cap M4 × 0.7 2 2 0.2 1.4
Rear brake hose union bolt M10 × 1.25 2 30 3.0 2.2
Rear wheel axle and axle nut M20 × 1.5 1 125 12.5 90
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
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
Engine bracket and frame M8 × 1.25 6 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
Left engine guard M8 × 1.25 2 23 2.3 17
Right engine guard M8 × 1.25 2 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 M8 × 1.25 3 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 case 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
Radiator cover M6 × 1.0 6 4 0.4 2.9
Front fender M6 × 1.0 4 7 0.7 5.1
Rear fender and air filter case M6 × 1.0 2 7 0.7 5.1
Rear fender and frame (right) M6 × 1.0 1 10 1.0 7.2
Side cover M6 × 1.0 2 7 0.7 5.1
Seat M8 × 1.25 2 23 2.3 17

SPEC
2 - 18
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 - 19
SPEC

CABLE ROUTING DIAGRAM
EC240000
CABLE ROUTING DIAGRAM
1
Hose guide
2
Brake hose
3
Voltage regulator
4
Light switch lead
5
Fuel tank breather hose
6
Engine stop switch lead
7
Clamp
8
Oil tank breather hose
9
Sub-wire harness
0
Taillight lead
A
Throttle position sensor lead
B
Neutral switch lead
C
Oil hose
D
Cylinder head breather hose
E
CDI magneto lead
F
Clutch cable
G
Cable guide
H
Carburetor breather hose
I
Carburetor overflow hose
J
Coolant reservoir breather hose
K
Decompression cable
L
Ground lead
M
Ignition coil lead
N
CDI unit lead
O
Voltage regulator lead
Å
Pass the fuel tank breather hose
behind handlebar, then insert it
into the steering stem hole.
ı
Pass the decompression cable,
engine stop switch lead and light
switch lead under where the oil
hose is attached.
Ç
Pass the voltage regulator lead,
engine stop switch lead and light
switch lead over the radiator
hose.
Î
Fasten the engine stop switch
lead, light switch lead and igni-
tion coil lead of the sub-wire har-
ness.
‰
Fasten the sub-wire harness
and engine stop switch lead.
Ï
Pass the cylinder head breather
hose along the right side of the
oil tank breather hose.
Ì
Fasten the sub-wire harness
and light switch lead in front of
the upper engine brackets.
Ó
Fasten the sub-wire harness.
È
Pass the sub-wire harness
between the upper engine
brackets.
Ô
Fasten the sub-wire harness.

Fasten the throttle position sen-
sor lead.

2 - 24
SPECCABLE ROUTING DIAGRAM
1Throttle cable
2Light switch
3Light switch lead
4Clamp
5Decompression cable
6Clutch cable
7Hose guide
8Trip meter
9Brake hose
0Engine stop switch leadÅFasten the engine stop switch lead to the handlebar with the plastic
band.
ıPass the throttle cables between the upper bracket and trip meter.
ÇPass the light switch leads behind the engine stop switch lead, then
pass the headlight lead (of the light switch leads) in front of the head
pipe.
ÎInstall the trip meter cable so that its bent portion faces the chassis
rear.
‰Install the brake hose so that it contacts the master cylinder projec-
tion and that its bent portion faces downward.

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 race
or
500 km
(300 mi)Every
fifth race
or
1,000 km
(600 mi)
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.
TIMING CHAIN SPROCKETS, TIMING
CHAIN
Inspect
Replace
●

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

●

●

●
Inspect crack
Remove carbon
PISTON RING
Inspect
Replace
●

●

●
Check ring end gap
PISTON PIN
Inspect
Replace
●

●

CYLINDER HEAD
Inspect and clean
●
Remove carbon
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
●

●