New English Made BSA Twins Crankshaft Timing Side Oil Pump Drive Gear Nut. If your Rebuilding your BSA only use High Quality Parts that you can trust! This Nut is Made to O.E.M. Specs! Nut has "Left Hand" Threads and the pitch is 20 TPI. Fits all BSA A50 & A65 Twins (Lightning, Royal Star, Wasp, Hornet, Thunderbolt, Etc) from 1962-1972. Also fits most BSA A7 & A10 Pre-Unit Twins (Goldenflash, Shooting Star, Rocket Goldstar, Etc) up 1963. Please refer to your parts catalog for proper fitment.   

•Made in the UK

•O.E.M Part number is 67-0643