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1-12
FUEL AND ENGINE MIXING OIL
GEN
INFO
EC160051
FUEL AND ENGINE MIXING OIL
Mix oil with the gas at the ratio specified below.
Always use fresh, name-brand gasoline, and mix
the oil and gas the day of the race. Do not use
premix that is more than a few hours old.
NOTE:
If knocking or pinging occurs, use a different
brand of gasoline or higher octane grade.
cC
Never mix two types of oil in the same
batch; clotting of the oil could result. If you
wish to change oil types, be sure to drain
the fuel tank and the carburetor float bowl
of old premix prior to filling with the new
type.
Fuel tank capacity:
8.0 L (1.76 Imp gal, 2.11 US gal)
Mixing oil
Recommended oil:
Yamalube “2-R”
(Yamalube racing 2-cycle oil)
Mixing ratio: 30 : 1
If unavailable, use an equivalent
type of oil.
Recommended fuel:
Premium unleaded gasoline
only with a research octane
number of 95 or higher.
1P8-9-30-1 19/5/04 9:00 AM Page 28
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2-1
GENERAL SPECIFICATIONSSPEC
Model name: YZ250T1 (USA, CDN)
YZ250 (EUROPE, ZA)
YZ250T (AUS, NZ)
Model code number: 1P81 (USA, CDN, ZA)
1P82 (EUROPE)
1P84 (AUS, NZ)
Dimensions:USA, ZAAUS, NZ EUROPE CDN
Overall length 2,179 mm←2,188 mm 2,186 mm
(85.8 in) (86.1 in) (86.1 in)
Overall width 827 mm←←←
(32.6 in)
Overall height 1,306 mm←1,310 mm 1,309 mm
(51.4 in) (51.6 in) (51.5 in)
Seat height 989 mm←992 mm←
(38.9 in) (39.1 in)
Wheelbase 1,481 mm←1,485 mm←
(58.3 in) (58.5 in)
Minimum ground clearance 383 mm←386 mm←
(15.1 in) (15.2 in)
Dry weight:
Without oil and fuel 96.0 kg (211.6 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 9.1~10.9 : 1 (Expect for EUROPE)
9.0~10.6 : 1 (For EUROPE)
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 Premium unleaded gasoline
only with a research octane
number of 95 or higher
Tank capacity 8.0 L (1.76 Imp gal, 2.11 US gal)
EC200000
SPECIFICATIONSEC211000
GENERAL SPECIFICATIONS
1P8-9-30-2 19/5/04 9:08 AM Page 2
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2-4
MAINTENANCE SPECIFICATIONSSPEC
Item Standard Limit
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 …
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 equivalent oil…
Carburetor:USA, CDN, ZA,
EUROPE
AUS, NZ
Type/Manufacturer
PWK38S/KEIHIN←…
I.D. mark 1P81 00 1P82 10…
Main jet (M.J.) #178 #180…
Main air jet (M.A.J) #200←…
Jet needle-clip position (J.N.) N3EJ-2 N3EW-3…
Main nozzle (N.J.) ø2.9←…
Cutaway (C.A.) #7←…
Pilot jet (P.J.) #50 #52…
Pilot air screw (P.A.S.) 1 7/8…
(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←…
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 107.8 mm (4.24 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) 0.63 L (0.55 Imp qt, 0.67 US qt)…
Water pump:
Type Single-suction centrifugal pump…
1P8-9-30-2 19/5/04 9:08 AM Page 5
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2-7
MAINTENANCE SPECIFICATIONSSPEC
EC212201
CHASSIS
Item Standard Limit
Steering system:
Steering bearing type Taper roller bearing…
Front suspension:
Front fork travel
300 mm (11.8 in)…
Fork spring free length
465 mm (18.3 in)460 mm (18.1 in)
Spring rate, STD K=4.3 N/mm…
(0.438 kg/mm,
24.5 lb/in)
Optional spring/Spacer Yes…
Oil capacity 430 cm
3…
(15.1 Imp oz,
14.5 US oz)
Oil grade Suspension oil …
“S1”
Inner tube outer diameter
48 mm (1.89 in)…
Front fork top endZero mm (Zero in)…
Rear suspension: USA, CDN, ZA,
EUROPE
AUS,NZ
Shock absorber travel
132 mm (5.20 in)←…
Spring free length
260 mm (10.24 in)←…
Fitting length
251 mm (9.88 in)253 mm (9.96 in)…
240.5~258.5 mm←…
(9.47~10.18 in)
Spring rate, STD K=48 N/mm ←…
(4.9 kg/mm,
274.4 lb/in)
Optional spring Yes←…
Enclosed gas pressure
1,000 kPa←…
(10 kg/cm2, 142 psi)
Swingarm:
Swingarm free play limit
End…
1.0 mm (0.04 in)
Side clearance…
0.2~0.9 mm
(0.008~0.035 in)
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INSP
ADJ
3-14
PILOT AIR SCREW ADJUSTMENT
4. Remove:
9Oil drain bolt 1
9Oil filler cap 2
Drain the transmission oil.
5. Install:
9Aluminum washer
9Oil drain bolt 1
6. Fill:
9Transmission oil
Recommended oil:
Yamalube 4 (10W-30) or SAE
10W-30 type SE motor oil
Oil capacity
(periodic oil change):
0.75 L (0.66 Imp qt, 0.79 US qt)
20 Nm (2.0 m•kg, 14 ft•lb)
7. Check:
9Oil leakage
8. Check:
9Transmission oil level
9. Install:
9Oil filler cap 2
EC35L021
PILOT AIR SCREW ADJUSTMENT
1. Adjust:
9Pilot air screw 1
Adjusting steps:
9Turn in the pilot air screw until it is lightly
seated.
9Turn out the pilot air screw by the factory-set
number of turns.
NOTE:
To optimize the fuel flow at a smaller throttle
opening, each machine’s pilot air screw has
been individually set at the factory. Before
adjusting the pilot air screw, turn it in fully and
count the number of turns. Record this num-
ber as the factory-set number of turns out.
Pilot air screw:
1 turn out
*7/8 turns out
(for reference only)
*For EUROPE
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5-32
CHASFRONT FORK
EC554600
Outer tube
1. Inspect:
9Outer tube 1
Score marks/Wear/DamageReplace.
Adjuster
1. Inspect:
9Adjuster 1
9O-ring 2
Wear/DamageReplace.
EC555000
ASSEMBLY AND INSTALLATIONEC5551D0
Front fork assembly
1. Wash the all parts in a clean solvent.
2. Stretch the damper assembly fully.
3. Fill:
9Front fork oil 1
To damper assembly.
cC
9Be sure to use recommended fork oil. If
other oils are used, they may have an ex-
cessively adverse effect on the front fork
performance.
9Never allow foreign materials to enter the
front fork.
Recommended oil:
Suspension oil “S1”
Oil capacity:
195cm
3(6.86 Imp oz, 6.59 US oz)
1P8-9-30-5B 20/5/04 2:11 PM Page 14