Yes it has been done IIRC.....back when the :"$21 mod" first came out. There wasn't a ton of uptake because there is nowhere near the improvement that there is with the front brake.
I don't know if you have a Gen1 or Gen2......I certainly wouldn't bother upgrading a Gen2 rear brake. As far as the Gen1 goes, mine are stock except for pads and a S/S line and I can lock up the rear on dry pavement at will so I decided that any time/expense on an upgrade was a waste......that said, my use is lightly loaded and I run knobbies; it's possible that with street tires and/or a heavy load or 2 up that the benefits may warrant the upgrade. ....In that case, it may be simpler to go with the Gen2 caliper and swingarm and there are other benefits to that (better chain adjusters, etc.)
....anyhow, that's the history.
Last edited by DPelletier; 02-17-2017 at 10:10 AM.