Before rebuilding and painting the calipers I wanted to sort out a way to simplify the brake lines. The stock '75 XS650 front brake line goes from hose to hard line, then the junction block and pressure switch, hose again and then back to hard line at the caliper.
Since the early two piston caliper doesn't use a regular banjo fitting, I'm using Russell adapters part # R41431 at the calipers. These come 2 to a package.
The nut portion of the adapter is bigger than the stock brake line and makes slight contact with the caliper.
The little ridge is where it touches...
...so just needed hit with a die grinder.
Now it fits without contact. This will let me use a standard braided brake line with 10mm banjo fittings at one end and -3 AN female at the caliper, eliminating the hard line. The stock single caliper master cylinder is 16mm, and the European market twin disc models are 22mm. These calipers have 48mm pistons, and according to the Vintage Brake chart it looks like 19mm(3/4") should be a good choice. I need to get one with the brake light switch built in, which will get rid of the pressure switch.