My bike is the 81 650-CSR & is virtually identical to yours.
The front brake is very doable. It was the first thing I refurbished - I'm not a mechanical genious but I'm no dumb-ox either. It's been a while, but I kinda recall that installing the dust seal was tricky. When reassembling everthing, your hands, the parts & work area must be spotlessly clean. Absolutely no grit.
An air compressor is handy for removing the caliper piston - be careful not to crush a finger. After disassembly, I cleaned mine thoroughly, then wet sanded it to prep it for painting. The stock paint is tough, so I only had to hit the pealing areas vigorously. After sanding, I blew it dry w compressed air. The auto parts store has brake caliper paint. After the paint cured, I baked the caliper in a low temp oven to harden it further, although it still isn't brake fluid proof.
