Need advice converting a suzuki into a bobber. (frame advice)?

[Eli]

im planning on tearing apart my 82 suzuki gn400 and making it into a bobber. im making forward controls out of either 1" to 1 1/4" plumbers tubing or round aluminum. converting it to a foot clutch/ jockey shifter. and making a pan seat. all that stuff is basically covered. comment on that stuff if you like. . . my problem is ive never welded before and dont know much about frame work. i want to make it into a rigid frame. i dont know what kind of tubing i need for the frame also if i need to keep the swing arm or not... ive seen some bobbers with them and some without. als what would need to be done to the carb with putting a performance air filter on it. think its jetting it from what i remember but this is my first project so any advice would be great. thanks guys.