Bsa Sloper Piston. 500cc. 1925-31 STD
upright and sloper
Measurements see last pict.
gudgeon pin 15,87 mm = 5/8"
S25,S26,S27,S28,S29,S30-9,S31-7 493cc ,SV 1925-31
Please look at all pictures
including gudgeon Pin, piston rings and circlips
Piston Clearance 0.12mm or 45thou