With the bike I'm not so sure but with a trike it is definately possible in PA. Just this month actually my brother and myself registered a 200m and a 200x, both had no titles. Upon calling DCNR they told me to fill out their application for each one and send in the fees for titles and registration along with a bill of sale. Since the trikes were obtained through a private transaction years ago they said to fill in unknown for the seller/seller's address/seller's phone number and fill in the correct buyer information which was us, and lastly we had to get each bill of sale notorized. The major problem was that the VIN on the 200m wasn't legible anymore so we had to take the 200m to the local police station and have them verify that it wasn't legible on one of their letterheads. The officer that assisted us was very kind and looked it over, jotted some notes down about it, and told us he'd send us a letter that he looked over it and he did. Once all this was taken care of we sent all that into DCNR and they issued a new VIN number with a special VIN plate for the 200m and titles/registration plates with stickers for both trikes. Yes it sounds like a lot to do and this post is getting long but when there aren't many places to ride and you want to ride at public places you gotta do what you gotta do. Hope this helps somehow.
Trikes
1984 Honda 200x, 1984 Honda 200m
Bikes
1995 Honda CR125R, 1985 Honda XL100 (gone), 1982 Kawisaki KZ550 LTD,
2001 Yamaha TT-R 125L, 1983 Honda XL185S (current project), 2001 Suzuki SV650S