If it's a Honda part it may be from a CB350 before they got disc brakes? There are other possibilities from the same era but most Honda front wheels did not have integrated speedo drives. I couldn't find a really good pic of a CB350 front wheel showing the left side.
Could also be a Suzuki X6 or similar, there were a lot of 36 spoke bikes in the 60s with DLS front brakes. Kawasaki, Suzuki, and Yamaha all had an integral speedo drive on some models at least.