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 (0.63 in) from the bottom of the skirt.
Piston Diameter

Standard (New): 72.969-72.979 mm (2.87279-2.87318 in)

Service Limit: 72.967 mm (2.87271 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 (2.87401-2.87460 in)

Service Limit: 73.065 mm (2.87657 in)

Oversize

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

Reboring limit: 0.25 mm (0.0098 in) max.

Bore Taper

Limit: (Difference between first and third measurement) 0.05 mm (0.0020 in)

Fig 2: Identifying Cylinder Bore Size
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 3: Measuring Cylinder Wear And Taper
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Scored or scratched cylinder bore must be honed.
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 (0.002 in) max.

Fig 4: 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 (0.00083-0.00181 in)

Service Limit: 0.05 mm (0.0020 in)

Fig 5: Inspecting Piston And Engine Block
Courtesy of AMERICAN HONDA MOTOR CO., INC.