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Thread: Rear master cylinder upgrade

  1. #1
    Senior Member AZmidget91's Avatar
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    Rear master cylinder upgrade

    So, a while back I did the hidden caliper upgrade using a P34 caliper. Which is a dual 34mm piston caliper. The braking was better, but still required a lot of effort and a solid pedal when it did engage. Doing some research I found the target for the caliper to master cylinder ratio, granted, it's not for rear brakes, but close and gives you a good idea.

    http://www.vintagebrake.com/mastercylinder.htm

    So, now knowing a little more about brakes, I found what it was stock 9:1... Not good if you want to actually feel the brakes. Now, I getting the ratio for the P34 and stock master cylinder was easy because the master cylinder has the size stamped on it, 1/2". Ok, so now with the P34 and the stock master cylinder it is 14.3:1, better, but still a "wooden" feel. Common rear master cylinder sizes are 11mm, 1/2"(12.7mm), and 13mm. So I made the chart below and added the P32 caliper for those who went with that for their hidden caliper.



    Now with that easy chart made up, it's easy to see that the 11mm master cylinder is going to be my best choice. So which one? Well, Brembo of course... So, off to the internet again to find a suitable 11mm master cylinder. Looking around, I found the PS11B, it's 11mm with a side exit for the brake line, which will hide the master cylinder behind the heel guard better. Cool! So, found one on ebay for cheap. Got the master cylinder and immediately noticed my first problem, no threads... Ok, so put helicoils in and now I have threads. Next issue, was my brake line, with the straight fitting, I either hit the belt, or the swing arm. So put on a 45 fitting to angle it forward and up to clear both, only had a chrome one laying around So now got the kinks worked out...well except for the push rod falling out if you accidentally pull up on the pedal, going to add a spring to keep it down, or a stop....

    Now, onto the test ride, I can now lock up the brake without putting my body weight on the pedal, just using those calf muscles. Yes, I know..."why would you want to lock up the rear tire" well, to quote a great man, "because I like to party." Many of you will think doing this is a waste, and not needed, but now I have more feel of what's going on with the brake, less effort, and more braking.

    Onto the pics!

    Comparison of the master cylinders.


    Mounted up and showing the 45 fitting on the brake line, will replace that chrome fitting for a black one soon.


    With the heel guard you only see the bottom poking out with the Brembo logo


    And of course, didn't have the right hose to fit the smaller reservoir up in the stock location.


    There are other master cylinders you can use. Some use an integrated reservoir.

    After I had done all this research, I then thought, hmm what bike did the P34 caliper come on? Monster 1100... hmm what master cylinder did that come with PS11... So, looks like I decided on the exact brake setup as a Monster. So, that just proves this isn't such a bad idea after all to all you negative Nancys out there.
    Last edited by AZmidget91; 02-19-2016 at 05:20 PM.

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  3. #3
    Awesome info, though I think in your chart you have the 34mm and 32mm switched.

  4. #4
    Senior Member AZmidget91's Avatar
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    You are correct, I moved them to be in order of size, but didn't move the nominal size.

    Fixed
    Last edited by AZmidget91; 02-19-2016 at 05:20 PM.

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    2 questions I have, and FIRST let me apologize if this has been covered somewhere else (I'm sure it has but I want to talk to people who are actively posting as opposed to old posts with users that might not be around any longer).

    1. The link you posted to the master cylinder, it doesn't have a push rod. But I noticed the one you had came with it. If I were to buy this reservoir from OPP would I be able to use my existing pushrod?

    and (yes, I know its somewhat off-topic, but you seem to know more than me so I'll ask anyway)

    2. What caliper would best be suited for the front with a 19mm Nissin radial MC? I know about the ZTL2 from Harley, but I would like to go with a brembo to match the rear. I saw plenty of older threads saying there were no Brembos out there but they were all several years old. I'm not tied to a Brembo, but I like options.

    Thank you so much in advance for all your help!

  6. #6
    Senior Member AZmidget91's Avatar
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    That master cylinder I posted from opp is a stock part on a 2012 Ducati Monster. I got one used with pushrod and reservoir on ebay. You could also buy the pushrod itself from Ducati if you want new parts. The Buell push rod might be able to be modified, but I would just get the Ducati part.

    Unfourtunately, there is no direct replacement brembo front brake caliper. Now anything is possible with a fork and wheel swap, but who would want to get rid of that giant rotor? Also, I went with a 16mm front master cylinder from a R6 and have great feel and power with my ZTL2.

  7. #7
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    So I ended up calling OPP to ask him about some of the calipers they offer. The guy who answered was super nice and informative. He told me that the MC is capable of using the OE Buell rod. He also told me that he needed to know if the front caliper was Axial or Radial, how it mounted and a couple of other questions that I didn't really have the answers to (at least while sitting at a desk at work!). So I'm supposed to send him some pictures and he'll send me some options. I already replaced my front MC with a 19mm Nissin off of a '08 zx10r. So, my Buell is a 2nd bike and isn't assembled currently, so I didn't know until I stumbled upon this thread that my upgraded MC wouldn't really work with the OE caliper. Thankfully I found out here and not on the road! I plan on upgrading both calipers and also the rear MC and want to go with gold colored for the calipers. So that's currently where I'm at. I want something to match this:

    https://secure.oppracing.com/product...ld-w-07bb2010/
    Last edited by am944; 03-16-2016 at 09:24 PM.

  8. #8
    Senior Member AZmidget91's Avatar
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    There is no bolt on Brembo option for the front.

    Here is a good fair priced ZTL2, it was very recently installed on a bike that ended up getting salvaged.
    http://www.ebay.com/itm/X-03-06-BUEL...QAAOSwP~tW6bls

  9. #9
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    Thanks for all your help man! That caliper sold quick, but I found them online new for not too much more. Thanks again!

  10. #10
    Senior Member AZmidget91's Avatar
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    Yeah, most people don't realize how much they go for new. That one I posted is probably the only one I have seen listed for less than the new price.



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