Hi vintage bikes,
Welcome to The Automotive India!
These bikes are quite rare so may not be easily available.
Check out the last advert. pages in Autocar, You may find your favourite vintage bike there.
Also, If you're living here in Delhi, Then there is a shop called "Vintage Cars & Bikes"(Not sure if name is correct but its something like this only)
in Palika Bhavan, Opp. Hayat Hotel. They always have some vintage cars and bikes in good condition, for sale. All the best.