Piston assembly (complete with piston, rings, gudgeon, circlips) to suit Norton ES2 1948 to 1958. 79mm std. Italian made by Gandini (GPM). Can be used for pre 1948 motors with large flywheels if the skirt length is relieved by machining/ grinding. Original Norton part number: 3790; A3/163 - Piston assembly with gudgeon pin A3/160; A3/161; A3/162; A3/163; A3/164