Here is a chart of Honda B series bearing thickness by color. To calculate actual bearing clearance, use the following formula:
BC = IDBT – ODC – (2 x BT)
BC = bearing clearance
IDBT = inside diameter of bearing tunnel (housing bore)
ODC = outside diameter of crank journal
BT = bearing thickness
Main Bearing thickness by color
Blue 2.013-2.010 mm 0.0793”- 0.0791”
Black 2.010-2.007 mm 0.0791”- 0.0790”
Brown 2.007-2.004 mm 0.0790”- 0.0789”
Green 2.004-2.001 mm 0.0789”- 0.0788”
Yellow 2.001-1.998 mm 0.0788”- 0.0787”
Pink 1.998-1.995 mm 0.0787”- 0.0785”
Red 1.995-1.992 mm 0.0785”- 0.0783”
Rod bearing thickness by color
Blue 1.510-1.507 mm 0.0594”- 0.0593”
Black 1.507-1.504 mm 0.0593”- 0.0592”
Brown 1.504-1.501 mm 0.0592”- 0.0591”
Green 1.501-1.498 mm 0.0591”- 0.0590”
Yellow 1.498-1.495 mm 0.0590”- 0.0589”
Pink 1.495-1.492 mm 0.0589”- 0.0587”
Red 1.492-1.489 mm 0.0587”- 0.0586”
Although most people do not have inside micrometers, bearing micrometers or snap gauges, you can still use this chart when using plastigage to check bearing clearance. If you want to increase or decrease a bearing clearance, you can calculate how much of a color change is necessary by looking at the changes on the chart. Remember you can mix colors for even a more fine-tuning but it would not be wise to jump more than one color. In other words, do not mix a brown and yellow bearing together to equal a green clearance value. Just use the greens together. It is ok to mix a green with a yellow or a green with a brown. When doing your rebuild and replacing bearings with like colors, you still must check your results with plastigage to be sure. Don’t assume anything. Also remember, when swapping to aftermarket rods, throw the color codes away as they will not work anymore. You need to start from scratch to obtain your desired clearance. On the other hand, you really cannot measure accurately to the nearest .0001” without machinist quality tools, so don’t get carried away on that last one ten thousandth of an inch variance.
