2001 YAMAHA YZ250LC width

2-1
GENERAL SPECIFICATIONSSPEC
Model name: YZ250LC (EUROPE)
YZ250N1 (USA)
YZ250(N) (CDN, AUS, NZ, ZA)
Model code number: 5MW1 (USA, CDN, ZA)
5MW2 (EUROPE)
5MW4 (AUS, NZ)
Dimensions: USA, CDN, ZA EUROPE AUS, NZ
Overall length 2,179 mm 2,178 mm 2,179 mm
(85.8 in) (85.7 in) (85.8 in)
Overall width 827 mm¬¬
(32.6 in)
Overall height 1,307 mm 1,302 mm 1,303 mm
(51.5 in) (51.3 in) (51.3 in)
Seat height 989 mm¬¬
(38.9 in)
Wheelbase 1,482 mm¬¬
(58.3 in)
Minimum ground clearance 392 mm 391 mm 392 mm
(15.4 in) (15.4 in) (15.4 in)
Basic weight:
With oil and full fuel tank 104.5 kg (230 lb)
Engine:
Engine type Liquid cooled 2-stroke, gasoline
Cylinder arrangement Single cylinder, forward inclined
Displacement 249 cm
3(8.76 lmp oz, 8.42 US oz)
Bore ´Stroke 66.4 ´72 mm (2.614 ´2.835 in)
Compression ratio 9.1~10.6 : 1
Starting system Kick starter
Lubrication system: Premix (30 : 1)(Yamalube 2-R)
Oil type or grade (2-Cycle):
Transmission oil Yamalube 4 (10W-30) or SAE 10W-30 type SE
motor oil
Periodic oil change 0.75 L (0.66 Imp qt, 0.79 US qt)
Total amount 0.80 L (0.70 Imp qt, 0.85 US qt)
Coolant capacity (including all routes): 1.20 L (1.06 Imp qt, 1.27 US qt)
Air filter: Wet type element
Fuel:
Type Except for AUS: Premium unleaded fuel
with a research octane
number of 95 or higher
For AUS: Unleaded fuel only
Tank capacity 8.0 L (1.76 Imp gal, 2.11 US gal)
EC200000
SPECIFICATIONSEC211000
GENERAL SPECIFICATIONS
2
5MW-9-30-2 7/3/00 2:19 PM Page 2

2-3
MAINTENANCE SPECIFICATIONSSPEC
Item Standard Limit
Cylinder head:
Combustion chamber capacity 21.5 cm
3…
(0.757 Imp oz, 0.727 US oz)
Warp limit…
0.03 mm (0.0012 in)
Cylinder:
Bore size 66.400~66.414 mm 66.5 mm (2.618 in)
(2.6142~2.6147 in)
Taper limit…
0.05 mm (0.0020 in)
Out of round limit…
0.01 mm (0.0004 in)
Piston:
Piston size/ 66.352~66.367 mm…
(2.6120~2.6129 in)
Measuring point* 17.5 mm (0.69 in)…
Piston clearance 0.045~0.050 mm 0.1 mm (0.004 in)
(0.0018~0.0020 in)
Piston offset 1.5 mm (0.059 in)/EX-side…
Piston pin:
Piston pin outside diameter 17.995~18.000 mm 17.975 mm
(0.7085~0.7087 in) (0.7077 in)
Piston ring:
Sectional sketch Plain…
B=1.0 mm (0.039 in)…
T=2.55 mm (0.100 in)…
End gap (installed) 0.40~0.55 mm (0.016~0.022 in) 0.95 mm (0.037 in)
Side clearance (installed) : 1st
0.030~0.065 mm (0.0012~0.0026 in)0.1 mm (0.004 in)
: 2nd0.030~0.065 mm (0.0012~0.0026 in)0.1 mm (0.004 in)
Crankshaft:
Crank width “A” 59.95~60.00 mm (2.360~2.362 in)…
Runout limit “C” 0.03 mm (0.0012 in) 0.05 mm (0.0020 in)
Connecting rod big end
side clearance “D” 0.25~0.75 mm (0.010~0.030 in)…
Small end free play “F” 0.4~1.0 mm (0.016~0.039 in) 2.0 mm (0.08 in)
Clutch:
Friction plate thickness 2.9~3.1 mm (0.114~0.122 in) 2.8 mm (0.110 in)
Quantity 8 …
Clutch plate thickness 1.5~1.7 mm (0.059~0.067 in) …
Quantity 7 …
Warp limit … 0.2 mm (0.008 in)
Clutch spring free length 44.0 mm (1.732 in) 42.0 mm (1.654 in)
Quantity 6 …
Clutch housing thrust clearance 0.17~0.23 mm (0.007~0.009 in) …
Clutch housing radial clearance 0.030~0.055 mm (0.001~0.002 in) …
Clutch release method Inner push, cam push …
EC212000
MAINTENANCE SPECIFICATIONSEC212100
ENGINE
5MW-9-30-2 7/3/00 2:19 PM Page 4

2-4
MAINTENANCE SPECIFICATIONSSPEC
Item Standard Limit
Transmission:
Main axle deflection limit…
0.01 mm (0.0004 in)
Drive axle deflection limit…
0.01 mm (0.0004 in)
Shifter:
Shifting type Cam drum and guide bar…
Guide bar bending limit…
0.05 mm (0.0020 in)
Kick starter type: Kick and ratchet type…
Air filter oil grade (oiled filter):Foam-air-filter oil or engine mixing oil…
Carburetor:USA, CDN, ZA,
EUROPE
AUS, NZ
Type/Manufacturer
PWK38S/KEIHIN¬…
I.D. mark 5MW00 5MW10…
Main jet (M.J.) #178 #180…
Main air jet (M.A.J) #200¬…
Jet needle-clip position (J.N.) N3EJ-2 N3CW-3…
Main nozzle (N.J.) ø2.9¬…
Cutaway (C.A.) #7¬…
Pilot jet (P.J.) #50 #55…
Pilot air screw (P.A.S.) 1 1-3/4…
(for reference only)
Valve seat size (V.S.)
ø3,8 mm (0,15 in)¬…
Starter jet (G.S.) #85¬…
Power jet (P.W.J.) #50 #55 …
Float arm height (F.H.) 5.5~7.5 mm¬…
(0.22~030 in)
Reed valve:
Thickness* 0.42 mm (0.017 in)…
Valve stopper height 10.3~10.7 mm (0.406~0.421 in)…
Valve bending limit…
0.2 mm (0.008 in)
Cooling:
Radiator core size:
Width 110 mm (4.33 in)…
Height 240 mm (9.45 in)…
Thickness 32 mm (1.26 in)…
Radiator cap opening pressure 95~125 kPa…
(0.95~1.25 kg/cm
2, 13.5~17.8 psi)
Radiator capacity (total) 0.64 L (0.56 Imp qt, 0.68 US qt)…
Water pump:
Type Single-suction centrifugal pump…
5MW-9-30-2 7/3/00 2:20 PM Page 5

4-52
WATER PUMPENG
EC4G3000
REMOVAL POINTS
EC4G3110
Impeller shaft
1. Remove:
9Impeller 1
9Plain washer 2
9Impeller shaft 3
NOTE:
Hold the impeller shaft on its width across the
flats awith spanners, etc. and remove the
impeller.
EC4G3210
Oil seal
NOTE:
It is not necessary to disassemble the water
pump, unless there is an abnormality such as
excessive change in coolant level, discoloration
of coolant, or milky transmission oil.
1. Remove:
9Bearing 1
2. Remove:
9Oil seal 1
EC4G4000
INSPECTIONEC444200
Impeller shaft
1. Inspect:
9Impeller shaft 1
Bend/Wear/Damage
ÕReplace.
Fur deposits
ÕClean.
5MW-9-30-4C 7/3/00 7:42 PM Page 8

4-54
WATER PUMPENG
EC4G5220
Impeller shaft
1. Install:
9Impeller shaft 1
NOTE:
9Take care so that the oil seal lip is not damaged
or the spring does not slip off its position.
9When installing the impeller shaft, apply the
lithium soap base grease on the oil seal lip and
impeller shaft. And install the shaft while turn-
ing it.
2. Install:
9Plain washer 1
9Impeller 2
NOTE:
Hold the impeller shaft on its width across the
flats awith spanners, etc. and install the
impeller.
3. Install:
9Dowel pin 1
9Gasket (water pump housing cover) 2
4. Install:
9Water pump housing cover 1
9Bolt (water pump housing cover) 2
9Copper washer (coolant drain bolt) 3
9Coolant drain bolt 4
10 Nm (1.0 m•kg, 7.2 ft•lb)
10 Nm (1.0 m•kg, 7.2 ft•lb)
14 Nm (1.4 m•kg, 10 ft•lb)
5MW-9-30-4C 7/3/00 7:43 PM Page 12

4-67
CRANKCASE AND CRANKSHAFTENG
EC4N5000
ASSEMBLY AND INSTALLATION
EC4N5300
Crankshaft bearing
1. Install:
9Bearing 1
To crankcase (left and right).
NOTE:
Install the bearing by pressing its outer race
parallel.
Standard
Runout 0.03 mm 0.05 mm
limit: (0.0012 in) (0.0020 in)
Small end 0.4~1.0 mm 2.0 mm
free play: (0.016~0.039 in) (0.08 in)
Side 0.25~0.75 mm
—
clearance: (0.010~0.030in)
Crank 59.95~60.00 mm
—
width: (2.360~2.362 in)
EC4N4202
Crankshaft
1. Measure:
9Runout limit a
9Small end free play limit b
9Connecting rod big end side clearance c
9Crank width d
Out of specification
ÕReplace.
Use the dial gauge and a thickness gauge.
2. Inspect:
9Bearings 1
Rotate inner race with a finger.
Rough spot/Seizure
ÕReplace.
3. Inspect:
9Oil seal 1
Damage
ÕReplace.
Dial gauge:
YU-3097/90890-01252
5MW-9-30-4C 7/4/00 9:27 AM Page 38