Remove the valves.

Measure the valve in these areas:

Intake Valve Dimensions
A Standard (New):	27.85−28.15 mm (1.096−1.108 in.)
B Standard (New):	100.4−100.9 mm (3.953−3.972 in.)
C Standard (New):	5.480−5.490 mm (0.2157−0.2161 in.)
C Service Limit:	5.450 mm (0.2146 in.)
Exhaust Valve Dimensions
A Standard (New):	25.85−26.15 mm (1.018−1.030 in.)
B Standard (New):	100.1−100.6 mm (3.941−3.961 in.)
C Standard (New):	5.450−5.460 mm (0.2146−0.2150 in.)
C Service Limit:	5.420 mm (0.2134 in.)