How do I transfer ownership if I bought a motorcycle without title ?

In My state, it requires lost title application  and $78. It's  Possible. I have  3 Harley

" sprints". this was all it took.  Those know-it-alls say "aint possible " have Never Tried It. I am not a liar, I can post it here.In Your unknown  location,. google your local DMV or Ministry Of Traffic, whatever.

There is a procedure .  So walk into a cop shop and ask them.  They know most of it. Auto insurance agents should also know too. DMV also knows.  It can be done and it will take about a month (without Covid)  That is the speed of the paperwork you got to do.

You can't, and you really didn't buy it.  You just gave money away.  Let me guess, you don't really know who sold it to you either.

You are free to drive it around your yard.

You need to have the previous owner apply for a lost title. You should never pay for a vehicle if there is no title!

The owner requests a duplicate title and signs it over to you.  You have NO legal standing to get a duplicate title.

1st apply for a lost title, then transfer it after they send it to you.......

Usually the DMV will need to do a title search - good luck.

That depends on the laws governing where you live dumdumb. It's a big world and this is an international forum. In many places you can't legally transfer ownership because you don't legally own it yourself. 

Per the procedures outlined at your local DMV office.