hooktool
XS650 Junkie
First off, I would recommend getting a bike and learning to ride before you shoot off building a death trap that resembles some un-ridable show horse.
I have found PLENTY of information by using the little search feature in the upper right corner of your screen. There is also a tech section and topics that discuss pretty much everything you have asked.
If you are trying to build a cheap bike, do that. There's no reason in the world to run a 180 on the back of a XS650 (unless you have plenty of money and a strong engine). Run a normal wheel or something you an install with the tools you have available. Meet local bike guys and join local forums. Having a broad network of friends will help you get things done cheap (and hopefully they will tell you when you dreams should become fairy tails).
I'm a newb too. But I realize that I can't just jump into building beauties without A.)
lots of money, or B.) Lots of time and research.
We are not the first people asking any of the questions we come up with. Even the dumbest shit you have ever conceived. SEARCHING will prove that. Good luck on the low buck build.
I typed "dumb shit" in the search box and got 18 results.
Renting a welder and doing it yourself would qualify as "dumb shit" unless you already know how to weld ( I assume OP doesn't), in which case you would probably own a welder.
Read here for a while and get a better idea of what you want. You really can get some answers here, but think about what you really want and you'll have better questions.
John