Front brake mc size

[John A]

 I’m going to put on another disc on Deb’s 02Stone because I’ve now gotten all the parts I need.  What size master cylinder do I use for a double disc non linked system?  I have that info at the shop and I’ll read over it but what experiences did you have with it?

[RinkRat II]

 Here's  some good info for what your doing.  Fun With Numbers!
     http://ducatimeccanica.com/brake_ratios.html

      Good Luck
     Paul B

[moto]

Another good source is Guzziology. You'll need to know the sizes of both your master and slave cylinders to get started.

[John Croucher]

Here are a couple of pictures on brake line routing I used to clean up appearance.
Bike originally had linked brakes. 
The right size m.c. will give you two finger braking.  To small and you will have a soft lever, to big and the lever will be hard with little braking.  Just guessing, I think I used a 14mm. on the front by Brembo.

[moto-uno]

  I might suggest you simply try it with what you have ( it may be fine , different , but fine) !   Peter

[Turin]

I like 14mm. 15mm also alright.

[skippy]

I found that when I converted my 03 Stone to a twin disc setup the 17mm master cylinder I sourced from an Apillia was just about perfect. Two finger operation would provide really good feel and feed back as well as haul the bike to a full stop with little effort.

Skippy 

[John A]

When I get the bike and measure what  master came on it with the original single disc I can get an idea of how it’ll work for two discs by the charts. Thanks for the replies

[Antietam Classic Cycle]

When I get the bike and measure what  master came on it with the original single disc I can get an idea of how it’ll work for two discs by the charts. Thanks for the replies

It should have a PS13 front master cylinder. The calipers are P4 30/34. Using an average of 32 mm for the 4 pistons, you'd end up with a 24.2 to 1 ratio. Just for reference, the V11 Sport used a PS16 with a pair of the same calipers.

[Tusayan]

Just for reference, the V11 Sport used a PS16 with a pair of the same calipers.

Which is equivalent to 5/8 inch, the typical master cylinder size used by almost everybody with those calipers.