Yamaha YZ250(W)/W1, Owner'S Service Manual

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MAINTENANCE SPECIFICATIONS
SPEC
Item Standard Limit
Cylinder head:
USA, CDN
EUROPE,
AUS, NZ, ZA
Combustion chamber capacity 21.0 cm
3
21.5 cm
3
…
(0.739 Imp oz, (0.757 Imp oz,
0.710 US 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)
: 2nd 0.030~0.065 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 50.0 mm (1.969 in) 48.0 mm (1.890 in)
Quantity 6 …
EC212000
MAINTENANCE SPECIFICATIONS
EC212100
ENGINE
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