5. Inspection and servicing of basic engine parts1785.1.5 Cylinder bore measurementEspecially clean head surface, cylinder bores andoil holes, and check the below items afterremoving any carbon deposit and bonding agent.(a) Appearance inspectionCheck if there is any discoloration or crack. Ifcrack is suspected, perform color check.Sufficiently clean the oil holes and check theyare not clogged.(b) Cylinder bore and distortionMeasure at 20 mm below the crest of the liner,at 20 mm from the bottom end and at thecenter in two directions A and B as shown inthe below figure.Roundness:Roundness is found as follows though it is thesimple method. Measure cylinder diametersof the A direction and the B direction on eachsection of a, b and c.Roundness is the maximum value amongthose difference values.Cylindricity:Cylindricity is found as follows though it is thesimple method.Measure cylinder diameters of a, b and csections in the A direction, and calculate thedifference in maximum value and minimumvalue of the measured diameters.In the same way measure and calculate thedifference in the B direction.Cylindricity is the maximum value betweenthose difference values.mmItem Standard LimitCylinder borediameter3/4JH4E 88.000~88.030 88.2004JH4-TE4JH4-HTE 84.000~84.030 84.200Cylinder roundness/ Inclination 0.01 or less 0.03010387-00X20 mm ABMeasure in two directionsA and B at points a, b and c.abc20 mm 001495-01E
