Norton crankcase cylinder stud set of 9, 3/8 inch, to hold cylinder barrel to front crankcase on Norton Commando twins 1971+. DOES NOT FIT EARLIER MODELS Original part number 062641 - cylinder-barrel-stud (front) [3/8 inch dia] x 1 062640 - cylinder base stud, stepped x 2 062639 - cylinder base stud x 6