Originally Posted by blaine.hale
I will never ever ever ever go to a handlebar mounted MC, I'm afraid.
I don't like hacking up stock parts to make something work and still not look elegant or stock. I also don't weigh more than 125lbs, which means the 1 r90 disc brake isn't THAT bad, especially with braided lines, 40mm pot and a fresh master cylinder rebuild. The stock r90s set up should be fantastic :)
Now that you've said that I'll chime in. Like you I didn't want to destroy the clean lines of the under tank M/C so I converted mine to dual disc by plugging two lines into the stock 14mm M/C. I used a banjo bolt instead of a compression fitting. I had to machine, read file, to get a good seal surface for the copper gasket but I'm very happy with the results.
Lever is a bit soft but brakes come in early in the travel and feel quite strong and progressive.
Here is a pic of the master cylinder banjo bolt setup: