Fitting Pistons

Check piston-to-bore clearance. See ENGINE SPECIFICATIONS tables at end of this article. Standard size pistons are color coded Red, Blue or Yellow on the piston dome. See PISTON SIZE CODE table in this article.
If bore diameter is in lower one-third of specifications, use a Red coded piston. If bore diameter is in middle one-third of specifications, use a Blue coded piston. If bore diameter is in upper one-third of specifications, use Yellow coded piston. The Yellow coded piston is .004" (.10 mm) oversize. Use proper size piston to acquire specified clearance.

PISTON SIZE CODES