Block and Piston Inspection

Remove the crankshaft and the pistons (see CRANKSHAFT AND PISTON REMOVAL ).
Check the piston for distortion or cracks.
Measure the piston skirt diameter (A) at a point 16 mm (0.6 in) from the bottom of the skirt.
Piston Diameter

Standard (New): 72.969-72.979 mm (2.8728-2.8732 in)

Service Limit: 72.967 mm (2.8727 in)

Oversize Piston Diameter

0.25: 73.219-73.229 mm (2.8826-2.8830 in)

Fig 1: Measuring Piston Skirt Diameter
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Measure wear and taper in direction Y at three levels in each cylinder as shown. If measurements in any cylinder are beyond the oversize bore service limit, replace the engine block. If the engine block is to be rebored, refer to step 7 after reboring.
Cylinder Bore Size

Standard (New): 73.000-73.015 mm (2.8740-2.8746 in)

Service Limit: 73.065 mm (2.8766 in)

Oversize

0.25: 73.250-73.265 mm (2.8839-2.8844 in)

Reboring limit: 0.25 mm (0.010 in) max.

Bore Taper

Limit: (Difference between first and third measurement) 0.05 mm (0.002 in)

Fig 2: Measuring Cylinder Bore Size
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Hone any scored or scratched cylinder bores.
Check the top of the engine block for warpage. Measure along the edges and across the center as shown.
Engine Block Warpage

Standard (New): 0.07 mm (0.003 in) max.

Service Limit: 0.10 mm (0.004 in)

Fig 3: Checking Engine Block Warpage
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Calculate the difference between the cylinder bore diameter and the piston diameter. If the clearance is near or exceeds the service limit, inspect the piston and the engine block for excessive wear.
Piston-to-Cylinder Clearance

Standard (New): 0.021-0.046 mm (0.0008-0.0018 in)

Service Limit: 0.05 mm (0.002 in)

Fig 4: Identifying Piston-To-Cylinder Clearance
Courtesy of AMERICAN HONDA MOTOR CO., INC.