Large or small diameter master cylinder for a single rotor brake setup?

[dufukincati]

Why do you have two clutch masters in your basket?

[Rudemouthsky]

Why do you have two clutch masters in your basket?

Twas an accident. I did think that seemed high.

I'm keeping these RCS masters I think. I'm starting to get really irritable...the lines I ordered came in, and aren't suitable for them. So the amount of $$ I'm flushing down the crapper is reaching absurd levels. Of course the vender won't take em back, because they're "custom", even though he ordered the wrong custom lines. Wah.

[manwithgun]

I'm a frugal bastard with a limited budget so the "fix it with cash" approach to things is only used in a time crunch.   On one of my single caliper set-ups (sumo/ 2-pad Brembo) I used a spare 999/749 clutch master (radial 15mm) and simply flipped it and modified accordingly.   Works fine for me but I don't recommend it.  Easiest, cheapest route would be to use the Brembo front brake master off of a 2007-2012 R6 (16mm).  I've also ran a single 4-pad caliper with the stock coffin master on my S2R with no complaints.   One thing to note is that the dual 4-pad set up is not necessarily the best performing set-up in my opinion.  With the stock pads and a coffin master, the initial bite was too aggressive for late braking and panic situations. A different pad compound may help remedy this, but there's a reason why most still use a 2-pad set-up.   The theory behind this is called "wedging" which implies that the square leading edge of a pad gets pulled into the braking surface upon contact and compounds initial bite.  this phenomenon is doubled with the 4-pad set-up.   To help remedy this, I chamfer the leading edge of all of my pads, as well as the bottom edge, to help make wheel swaps a bit easier.   Of course, with the single caliper set up and/or your riding style, the 4-pad may be perfect as is .