My usual source doesn't have the parts diagram for the XS750, so I was pretty happy to find someone else with an on-line parts diagram for the bike: www.powersportsplus.com. 'Course, a lot of the parts are no longer available, sigh...
Edit: Found another parts diagram/cross-reference index at www.benefiscal.co.uk.
Mike's XS to see how much a new caliper cost, and they were out of stock. There are a couple of calipers available on E-Bay, but I've already replaced the master cylinder with the master cylinder from a Fazer 750 (well...I will once it gets here). I'm ordering new stainless steel brake lines from SV Racing, and now I need new calipers, too?
Which raises a very good question...rather than try to source 35 year old parts for the bike, why don't I just retrofit modern brakes? If I'm wanting to build a naked sport bike from the XS750 frame and engine, wouldn't it just be better to retrofit new parts wherever possible? I'd have to fab up a brake caliper adapter to convert the bolt spacing on the replacement calipers to the spacing on the forks, but that's doable.
However, there's that whole "integrated system of related parts" concept that I figured out a little while ago. I measured the rotor on my DL-650, and it's about half the thickness of the XS750's brake rotor, which means I can't just slap on a pair of Tokico brakes like I have on my DL-650 unless I also replace the rotors, but the rotors have to mount to the carriers, and the carriers have to mount to the hub...
I read a build thread somewhere on-line about a guy who swapped the entire front end from an SV-650 to his XS750 -- wheel, forks, triple-tree, and brakes. He did some research and found that the SV-650 has the same size steering bearings, so it was a direct fit. That might be the best way to go, since it would give me a more modern suspension and brakes that I could actually, you know, find parts for. The down side, however, is that his front wheel had three spokes while the rear had...well, however many the XS750 has (hint: it's more than three, by quite a bit). The bike looked great, except for the mismatched wheels. I really don't like those three spoke wheels Suzuki puts on its bikes (just don't tell my Wee-Strom!).
Maybe I'll just pick up some used calipers on E-Bay after all. It's a lot easier, and I don't really have the tools or the knowledge to fab up a bunch of custom parts right now. Or, I guess I could always try to drill out the bleeder valve in my calipers, get a helicoil kit and repair the threads and install a new bleeder valve. I still need to break the piston loose, though. Maybe some penetrating oil and a hammer might do the trick? I also read about a way to repair rust inside a fuel tank by filling the tank with a solution of baking soda and water, and applying an electric current to reverse the oxidation process...maybe that would work on the brake piston? Okay, maybe as a last ditch effort if the penetrating oil and hammer don't do the trick, so I've got nothing else to lose.
I'll document the process here as it occurs :)