My favourite vintage motorcycle would have to be the iconic Indian Scout 101 built between 1928 and 1931. It's widely acclaimed as the best model built by the original Indian company and the basis of 'The World's Fastest Indian' at Bonneville. If you're interested, I wrote a Super Models review of Indian motorcycles for the Shannons Club: https://www.shannons.com.au/club/news/super-models/indian-scout-190mph-the-worlds-fastest-indian/