Genuine Parsun seat, valve stem 166F-010003 is compatible with Yamaha 51Y-12119-00
Ships from Sweden next business day and should be with you within a week
2 pieces "seat, valve stem 166F-010003" are being used on the page "F2.6 camshaft and valve"
They are sold one by one, if you need a complete set you need to buy multiple.