1/4" NPT plug zinc plated

Socket head plugs for blocking of oil or vent holes when changing the lubrication or venting system. For example when changing from chain to belt primary on a pre 1984 Big Twin, you must block of the front chain oiling system. This can be done by removing the fitting and installing the 1/16" NPT plug. 1/4" NPT and 1/8" NPT plugs are used to block vent holes on crankcases etc.