Soichiro, I get your point. However, is this possible with someone like me who have very limited knowledge of bikes? I'm sure these guys work on bikes 24/7. I'll give it a shot though.
Yes, I think it's possible. I mean, unless you're all thumbs. But look at the opportunity in front of you to learn all these new things! You can learn welding, and fabricating, and electrical wiring, and carburetor tuning, and on and on. But ultimately, you're going to have to make the decision whether you think you're up to it or not. I have a friend that couldn't build a wood box to save his life. Nothing wrong with that, but I'd say he probably shouldn't invest too much money in a project like this. You'll have to be the judge. And the place to start is browsing those other forums to see what everyone's doing. If you just want a basic cafe (I'd say like mine, minus the engine work), then yes, that is something almost anyone can do.
When I got mine, it was a stock CB 750. It ran, and it ran fairly well, except for a little oil leakage. The first thing I did was change the look of the bike. The photos in my intro thread are what it looked like before "Phase II". Phase II was engine modifications. Now... I put a lot of money into the engine, and it's not stuff for someone with a limited budget, but I looked at it as an education on auto mechanics. I didn't know the first thing about engines before I tore mine apart. I was handy with the tools because I have a machinist background, but that was it. Phase III will be an alloy CR-style gas tank and cleaning up the area under the seat. Maybe a new seat too. I plan to make the tank and seat myself, but who knows? Plans get modified.
If you take on a project like this, you'll need friends in real life that can help with the work (such as maybe a friend with a welder, etc.), and you'll need friends on the internet that can give advice and explain how to do stuff and where to get parts. Maybe there'll be a guy on a cafe forum that lives near you? You never know...
But yes, it's not going to be easy. But it's a great opportunity to learn. And once it's done, and you've seen the inside of the engine, and you know how to clean the carbs, and set the timing, and you can recognize that your timing's off or you need to adjust the tappets by the sound of the engine... you'll never worry about the bike breaking down because, a. you'll be on top of it way before it ever gets to that point, and b. you'll know how to fix it. But it will take a little time and dedication to get to that point.
I do strongly suggest getting a runner though, so you can ride it right away, and modify it in stages. Maybe dedicate one weekend to swap handlebars, maybe another for the seat, etc. And if you live in a cold-winter state like me, then you'll have the whole winter to work on it.
Well, now here's a big question that I almost neglected...
Do you have a garage? Or some place to work in? Can you bring the bike (or bike parts) into your house or apartment if you don't have a garage? You'll need a place to work.
Also, some of your budget money will go towards tools. So factor that in.