Rod Bearing Selection

Each rod falls into one of four tolerance ranges (from 0 to 0.024 mm (0.0009 in.), in 0.006 mm (0.0002 in.) increments) depending on the size of its big end bore. It's then stamped with a number or bar (1, 2, 3 or 4) indicating the range. You may find any combination of 1, 2, 3 or 4 in any engine.

Normal Bore Size: 43.0 mm (1.693 in.) 

1. Inspect each connecting rod for cracks and heat damage.

Connecting Rod Big End Bore Code Locations 

2. Numbers have been stamped on the side of each connecting rod as a code for the size of the big end. Use them, and the letters stamped on the crank (codes for rod journal size), to choose the correct connecting rod bearings. If the codes are indecipherable because of an accumulation of dirt and dust, do not scrub them with a wire brush or scraper. Clean them only with solvent or detergent.
   Fig 1: Identifying Connecting Rod Journal Code Location

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
   Fig 2: Identifying Big End Bore Codes & Rod Journal Codes Chart

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
3. Connecting Rod Journal Code Location 
   Fig 3: Identifying Connecting Rod Journal Code Location

   Courtesy of AMERICAN HONDA MOTOR CO., INC.