Cool, I'll just rebuild the stock MC then. I compared the pictures in the Ebay listing quite a bit to whatever else I could find. There was no year listed on this specific listing but they looked identical to a pair of 81 750f calipers. Comes with the mounting brackets so it sounds like they should work just. I'm getting anxious to get them and slap them on.
How much of an improvement is there in braking over stock? I haven't driven the bike since I got it so by the time these brakes are on and working I'll be taking my first ride on her, so I have nothing to compare to.
Generally speaking the one time ultimate stopping power is determined by the capacity of the master cylinder. Multiple discs and driven pucks give an advantage everywhere else EXCEPT the ultimate one time stopping power. Like reduced puck wear by spreading the same power over more area, reduced fading (biggest advantage), reduced heating of the fluid (more fluid in more lines) more symmetry of feel in the fork etc.
The stock one disc, one driven puck system puts it all on the line one time, then fades into oblivion by the third or fourth panic stop, equivalent to a few laps around the track.
I'll add to that what's already been stated: by changing hardware, you may get more access to compounds, rotor material, and the like which will improve the ultimate braking force without changing the master cylinder. But if all one is doing is (not you) converting a stock system to a dullie with stock parts, the master cylinder rules as far as "power" is concerned.
