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 diameter (A) at a point 16 mm (0.6 in.) from the bottom of the skirt.
Piston Diameter
- Standard (New): 72.98-72.99 mm (2.8732-2.8736 in.)
- Service Limit: 72.97 mm (2.8728 in.)
Oversize Piston Diameter
- 0.25: 73.23-73,24 mm (2.8831-2.8835 in.)
Fig 1: Checking Piston Diameter
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Measure wear and taper in direction X and 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): 73.00-73.02 mm (2.8740-2.8748 in.)
- Service Limit: 73.07 mm (2.8767 in.)
Oversize
- 0.25: 73.25-73.27 mm (2.8839-2.8846 in.)
Reboring limit: 0.25 mm (0.01 in.) max.

Bore Taper
- Limit: (Difference between first and third measurement) 0.05 mm (0.002 in.)
Fig 2: Checking Cylinder Bore Size
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Scored or scratched cylinder bores 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 (0.003 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 engine block for excessive wear.
Piston-to-Cylinder Clearance

Standard (New): 0.010-0.040 mm (0.0004-0.0016 in.)

Service Limit: 0.05 mm (0.002 in.)

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