Yamaha WR250R Service Manual page 28

Spark plug (s)
Manufacturer/model
Spark plug gap
Cylinder head
Volume
Warpage limit
Camshaft
Drive system
Camshaft cap inside diameter
Camshaft journal diameter
Camshaft-journal-to-camshaft-cap clearance
Limit
Camshaft lobe dimensions
Intake A
Limit
Intake B
Limit
Exhaust A
Limit
Exhaust B
Limit
B
Camshaft runout limit
Timing chain
Model/number of links
Tensioning system
Valve, valve seat, valve guide
Valve clearance (cold)
Intake
Exhaust
Valve dimensions
Valve head diameter A (intake)
Valve head diameter A (exhaust)
A
2-3
ENGINE SPECIFICATIONS
NGK/CR9EK
0.6–0.7 mm (0.024–0.028 in)
3
15.36 cm (0.94 cu.in)
0.05 mm (0.0020 in)
Chain drive (left)
22.000–22.021 mm (0.8661–0.8670 in)
21.959–21.972 mm (0.8645–0.8650 in)
0.028–0.062 mm (0.0011–0.0024 in)
0.08 mm (0.0031 in)
34.550–34.650 mm (1.3602–1.3642 in)
35.450 mm (1.3957 in)
25.953–26.053 mm (1.0218–1.0257 in)
25.853 mm (1.0178 in)
34.850–34.950 mm (1.3720–1.3760 in)
34.750 mm (1.3681 in)
25.986–26.086 mm (1.0231–1.0270 in)
25.886 mm (1.0191 in)
0.015 mm (0.0006 in)
98XRH2010-118M
Automatic
0.13–0.20 mm (0.0051–0.0079 in)
0.23–0.30 mm (0.0091–0.0118 in)
29.90–30.10 mm (1.1772–1.1850 in)
24.40–24.60 mm (0.9606–0.9685 in)