Yamaha YZ250 2022, Owner'S Service Manual

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ENGINE SPECIFICATIONS
2-2
EAM20128
ENGINE SPECIFICATIONS
Engine
Combustion cycle 2-stroke
Cooling system Liquid cooled
Induction system Reed valve
Displacement 249 cm³
Number of cylinders Single cylinder
Bore

stroke 66.4

72.0 mm (2.61

2.83 in)
Compression ratio 8.9–10.6 : 1
Starting system Kickstarter
Fuel
Recommended fuel Premium unleaded gasoline (E10 acceptable)
Fuel tank capacity 7.0 L (1.8 US gal, 1.5 Imp.gal)
Engine oil
Recommended brand YAMALUBE
Lubrication system Premix lubrication
Engine oil YAMALUBE 2R
Premix ratio 30
Transmission oil
Type Motor oil SAE 10W-40 type SG or higher
Quantity (disassembled) 0.80 L (0.85 US qt, 0.70 Imp.qt)
Quantity 0.75 L (0.79 US qt, 0.66 Imp.qt)
Cooling system
Coolant quantity
Radiator (including all routes) 1.20 L (1.27 US qt, 1.06 Imp.qt)
Radiator cap valve opening pressure 93.3–122.7 kPa (0.93–1.23 kgf/cm², 13.5–17.8
psi)
Spark plug(s)
Manufacturer/model NGK/BR8EG
Spark plug gap 0.5–0.6 mm (0.020–0.024 in)
Cylinder head
Warpage limit 0.03 mm (0.0012 in)
Cylinder
Bore 66.400–66.414 mm (2.6142–2.6147 in)
Wear limit 66.464 mm (2.6167 in)
Piston
Piston-to-cylinder clearance 0.045–0.050 mm (0.0018–0.0020 in)
Diameter 66.352–66.367 mm (2.6123–2.6129 in)
Measuring point (from piston skirt bottom) 17.5 mm (0.69 in)
Piston pin bore inside diameter limit 18.040 mm (0.7102 in)
Piston pin outside diameter limit 17.975 mm (0.7077 in)
Piston-pin-to-piston-pin-bore clearance 0.004–0.020 mm (0.0002–0.0008 in)
Piston ring
Top ring
End gap limit 0.95 mm (0.0374 in)
Ring side clearance 0.030–0.065 mm (0.0012–0.0026 in)
Side clearance limit 0.100 mm (0.0039 in)