Set of 8 new Triumph 12 point cylinder base buts. They are for Triumph 500 and 650 from 1969 to 1972. The thread is 3/8-24 UNF. If you are rebuilding or justcleaning up your motorcycle these are an easy change to make. If you need anything else for your top end from pistons, seals to gaskets-we can help. We have over 10,000 partsavailable and also offer free technicaladvice,just ask.