Piston Ring Replacement

Remove the piston from the cylinder block (see Crankshaft & Piston Removal ).
Using a ring expander (A), remove the old piston rings (B).

Fig 1: Removing The Old Piston Rings
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Clean all the ring grooves thoroughly with a squared-off broken ring, or a ring groove cleaner with a blade to fit the piston grooves. File down the blade if necessary. Top ring and second ring grooves are 1.2 mm (0.05 in.) wide, and the oil ring groove is 2.8 mm (0.11 in.) wide. Do not use a wire brush to clean the ring grooves, or cut the ring grooves deeper with the cleaning tool.
NOTE: If the piston is to be separated from the connecting rod, do not install new rings yet.
Using a piston, push a new ring (A) into the cylinder bore 15-20 mm (0.6-0.8 in.) from the bottom.

Fig 2: Pushing A New Ring Into The Cylinder Bore
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Measure the piston ring end-gap (B) with a feeler gauge:
- If the gap is too small, check to see if you have the proper rings for your engine.
- If the gap is too large, recheck the cylinder bore diameter against the wear limits (see step 4 on Block & Piston Inspection ).
If the bore is over the service limit, the cylinder block must be rebored.

Piston Ring End-Gap

Top Ring

Standard (New): 0.20-0.35 mm (0.008-0.014 in.)

Service Limit: 0.60 mm (0.024 in.)

Second Ring

Standard (New): 0.40-0.55 mm (0.016-0.022 in.)

Service Limit: 0.70 mm (0.028 in.)

Oil Ring

Standard (New): 0.20-0.70 mm (0.008-0.028 in.)

Service Limit: 0.80 mm (0.031 in.)
Install the rings as shown. The top ring (A) has a 1D mark and the second ring (B) has a 2C mark. The manufacturing marks (C) must be facing upward.

Fig 3: Installing The Rings
Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 4: Piston Ring Dimensions
Courtesy of AMERICAN HONDA MOTOR CO., INC.
After installing a new set of rings, measure the ring-to-groove clearance:
Top Ring Clearance

Standard (New): 0.055-0.080 mm (0.0022-0.0031 in.)

Service Limit: 0.13 mm (0.005 in.)

Second Ring Clearance

Standard (New): 0.030-0.055 mm (0.0012-0.0022 in.)

Service Limit: 0.13 mm (0.005 in.)

Fig 5: Measuring Ring-To-Groove Clearances
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Rotate the rings in their grooves to make sure they do not bind.
Position the ring end gaps as shown:

Fig 6: Positioning The Ring End Gaps
Courtesy of AMERICAN HONDA MOTOR CO., INC.