Tak'in care of Bizz - 3 front brake alternative mods

[Pursuvant]

If you don't like the wooden feedback of ABS brakes, or if you have physical disabilities that weaken your mitts like me, have a look at three possible mods to getting more physical power and feedback over the ABS brakes (XSR7 template).

Background:
My hands are loosing strength to cancer, so I'm working how to generate more physical power over the front brakes that allow me to continue one finger braking. ABS brakes take away a lot of the feel over, the feedback, of a good braking system. Did you know the XSR solid brake lines are smaller inside ID than rubber or braided stainless steel brake lines? Neither did I till I started working this mod. Rubber has always given up (to some degree) feel and power when they swell under pressure. Stainless steel braided lines, no not really.

What I need/want here, is to (1) gain as much physical leverage over the master cylinder piston as possible for my weakening hands, (2) minimize/eliminate wooden brakes feeling & lack of feedback, (3) replace those smaller diameter solid steel brake lines.

Only front brake is of consideration here on ABS XSR7. Assume sintered brake pads already installed. So what's possible for this type mod?

Mod A

This would be the answer, except no one will sign off on using the Brembo RCS17 on my XSR ABS bike. Aprilia factory warned a customer not to use any radial control system master cylinder on their ABS, it could overpower selenoid and cause unprovoked total lockup of brakes disaster. My speedshop owner agrees, there is real risk here with unknowable consequences.

So my best option, to switch the oem master cylinder to a Brembo radial control master is not acceptable. That would have gave me the leverage (power) over the system I was looking for.

Mod B

A version of the dual pickup at the master cylinder idea that uses two lines all the way from the master to each caliper, only in this ABS world one stainless steel braided brake line would drive from the master cylinder to the ABS IN, and then the OUT side of the ABS would have the dual pickup banjo bolt and 2 dedicated lines, one for each caliper up front. Removes the OEM stock rubber hose and solid steel brake lines and goes SS braided brake line all the way.

Mod C

Same as Mod B, except it uses a serial arrangement to drive both calipers. Braided stainless steel line connects the ABS OUT to both calipers, it follows the XSR default routing of brake lines so it's more convenient - the brackets and grommets are already there, just remove the OEM stock rubber hose and solid steel brake line and replace with SS braided brake line all the way.


I could use your help. The chemo has been wrecking my memory - the things I think I know and remember are not always accurate, and there are always things that are outside of what I know. Anyone interested in this stuff, could you please desk check what I'm doing here and advice would be great.

I'm ready to implement C because I think the power and feeling would be the same as B, but uses all the stock routing so mounting those stainless lines would be easier and look more attractive. I don't think B would feel more powerful, but I want to know did I miss any opportunities here, or is there some other risk.

Alternatives could include something like salvaging an R6 master cylinder but would I be in the same situation - could that master generate more power than the ABS can tolerate and crash the system/lock the brakes?

I also could pull two of the three fuses and disable the ABS, leave the one fuse that allows speedometer/odometer functioning. Then do as we always did in the past with non-ABS bikes - use a dual pickup banjo bolt at the master cylinder and run two braided stainless steel lines, each dedicated to one of the front calipers. That always works and gives great power and feedback. When those brakes bite, you are there - very little movement of the lever after that - the power and feel is really there. Insurance company would cancel me, and resale of this bike would be problem.

Disclaimer: DON'T DO ANY OF THESE MODIFICATIONS. DON'T DO THIS. IT CAUSES FOOT FUNGUS. THESE ARE STUPID IDEAS THEY WILL HURT OR KILL YOU.

 

 

[mossrider]

Ready, set, go on 3.

Just please, under the circumstances, get a trusted second party to double check your work before heading on down the highway. Always a good idea anyway. 

[stickshift]

Geez, the ABS doesn't half complicate things...

Without ABS you could just chuck on a RCS19, braided lines and some sintered pads.

[klx678]

Even with a master cylinder size change the following remains constant:

• The fluid volume, to be moved through the lines to the brake calipers, remains the same to move the caliper pistons the distance needed.
• It will still take equal pressure in the line to provide equal pressure at the pads
• To activate, the ABS works with varying line pressure, dealing with the wheel speed. Otherwise it wouldn't work on slippery surfaces at low brake pressure or it wouldn't work on dry surfaces at high brake pressure. In addition if it was pressure, how would it work with the variable grip strengths of different riders?

So if nothing related to the master cylinder is actually connected directly at the master cylinder it would make sense that the ABS remains unaffected with the different master cylinder. Your weakened grip would be compensated for giving the equivalent pressure of a strong rider with the stock system.

Think about it. You are working to try to maintain essentially the same pressure in the system. The system does not "see" the size of the master cylinder. It only reacts to the wheel rotation and the pressure that is in the line, whatever that pressure may be. As for "over powering" if that is possible why doesn't it happen when a rider with an exceptionally strong grip squeezes the lever full strength in a panic stop? I am betting there are riders with twice the grip strength I have and that system has to be able to deal with both.

One other thing - contact the maker of the ABS system.   Brembo answered on the  master cylinder size, maybe the ABS company will respond if there is a risk with the higher pressure.   The idea of overpowering a hydraulically operated selenoid questions the margin of safety engineered into the operation of that selenoid.  What pressure would it take to make it not activate?  How much safety factor do they have with that system?   Doesn't make sense that a minor increase in hydraulic leverage should override the selenoid.

[Pursuvant]

3 hours ago, klx678 said:

The idea of overpowering a hydraulically operated selenoid questions the margin of safety engineered into the operation of that selenoid.  What pressure would it take to make it not activate?  How much safety factor do they have with that system?   Doesn't make sense that a minor increase in hydraulic leverage should override the selenoid.

I was hoping you would jump in here with your analysis MK, thx Sir!

Thx for the primer, and you hit the ball out of the park with your questions for ABS mfgs.

Here is the link to Aprilia  freak telling a customer front wheel will lock/ruin your day/void warranty.

So it's a risk, unquantified, and I'm not taking it. I'll disable ABS if I get that weak in my hands, go full blown Brembo RCS17 with dual pickup at the master cylinder, with twin dedicated braided brake lines all the way, one line for each caliper, with no ABS physically connected in front brake circuit.

Edited August 3, 2020 by Pursuvant

[klx678]

I'd still contact the maker of the ABS. 

I'm actually betting it has no effect on the ABS, because nothing is connected to the master cylinder dealing with the ABS and what is physically happening with the fluid down line pretty much doesn't change.  XX psi for given braking power at the caliper and XX cc of fluid to move the pistons the distance stays the same, just less lever pressure to do so and there is no connection between the master cylinder and the ABS.  It is all down stream.

I just sent out a reply to Brembo from my original inquiry asking if there is any reason why the master cylinder should make any difference in the ABS actuation.  After all, they knew they were looking at an installation on an XSR700 which has ABS.   So I guess I wait to see what they reply for verification.

I am not surprised the manufacture would recommend against the change, since they would recommend against anything they may engineer for the bike.

Here is a link to Carpimoto Italy, they list the MT-07 FZ-07 with ABS for the 17 RCS, which might be similar to the XSR.  In the Q/A they answer a question about using the MS with an MT-09 and the reply was no problem if just replacing the MS.  I would think the problems would arise if switching calipers.

 

 

 

For the benefit of anyone considering the Brembo, here is the email I received:

Thank you for the email to Brembo Italy.  Your request was forwarded by Brembo to Race Technologies to support you.  Race Technologies is the importer and commercial partner for the Brembo Motorcycle program in North America.

Thank you for the inquiry and desire to install a Brembo master on you XSR700. You are correct in your explanation “18mm would give maximum pressure with least effort, but have most lever travel”.  The 18mm ratio setting offers more modulation.  The 20 setting has a shorter lever throw. 

But the 15 RCS is a little too small.  The 17 RCS is a better fit for the dual sided 4 piston calipers on the Yamaha XSR700.  The 17 RCS 110A26340 or the 17 RCS Corsa Corta 110C74040 would be a better fit.  Please let us know if you have any other questions or would like us to put you in touch with an Official USA Brembo Moto Dealer. 

http://moto.brembo.com/en/detail/110C74040

http://moto.brembo.com/en/detail/110A26340

here is a good article from magazine. 

https://www.motorcycle.com/products/mo-tested-brembo-19-rcs-corsa-corta-master-cylinder

 

Kind Regards,

Nicole Lavash, Senior Account Manager

Motorcycle Program

-------------------------------------------------------------------------------
Race Technologies, LLC | Brembo Official Partner
17422 Murphy Avenue, Irvine, CA 92614

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Office: (714) 438-1118  x 160  |  Fax: (714) 438-1119

Edited August 3, 2020 by klx678

[cornerslider]

I'm a big fan of ABS.... I've even been "saved" by ABS on an "off-track-adventure" on my 2016 KTM RC390 while hauling' a$$  through the wet grass ..... That being said, I don't like the budget-minded ABS that come on the FZ/MT's. I actually cancelled my order on a 2020 MT-03 because  the ABS was "standard". I bought a new R3 instead (for the street). I like the freedom to upgrade my brakes as I see necessary on all my bikes. Yes, I know I can "technically" do it with ABS, but ABS really complicates the entire brake system. I don't really trust the "budget-minded" ABS that is now the standard on all the MT's. If Yamaha put just a little more effort into the brakes, rather than a "race to the bottom line", I'd be more onboard. Rubber brake lines are are pretty much a joke to me- what are we living in 1974?

My 2016 KTM RC390 was still a "budget-minded" ABS system.... At least KTM had the foresight to put steel braided brake lines on the ENTIRE ABS system... KTM gave me the option to "disable" the ABS system, or go "supermoto mode", and remove the ABS from only the rear wheel.  I tried it in all "modes" on track, and couldn't tell any difference? That was my first ABS-equipped bike. I was over-all impressed with the ABS system. I was actually able to "overheat" my front rotor enough to warp the rotor without the ABS engaging.... That  caused a "pad-knock" situation enough to cause a pretty serious "OH-$hit" moment at the end of a long straight!!! 

I'm all about a well engineered ABS system, that suits my needs... I feel Yamaha dropped the ball on the current ABS that is now "standard" on the MT-07/03. You can't even "disable" the current ABS system without pulling the ABS fuse (causing an "error code". I can't honestly speak on the current MT-09/10, as I have zero experience with either of those bikes-

[klx678]

Now the final word from Brembo's rep, no problems swapping the master cylinder:

 

 

Brembo has confirm that the RCS masters (especially when paired with the proper size RCS) is compatible with the ABS system. 

You are good to run the 17 RCS with ABS.   ABS is at most more difficult to bleed.   

Thank you, 

Nicole Lavash, Senior Account Manager

Motorcycle Program

-------------------------------------------------------------------------------
Race Technologies, LLC | Brembo Official Partner
17422 Murphy Avenue, Irvine, CA 92614

----------------------------------------------------------------------------------------
Office: (714) 438-1118  x 160  |  Fax: (714) 438-1119
----------------------------------------------------------------------------------------
www.racetechnologies.com | www.facebook.com/race.technologies

[Pursuvant]

8 hours ago, klx678 said:

Now the final word from Brembo's rep, no problems swapping the master cylinder

You are a great amigo Mr MK!  You just picked up my problems and did all the work, and ran with your results into the end zone.

I will be able to ride who knows, several more years, because what you did here to help me. And how many others when they see this awsome mod rolled out, will jump on it because it is the solution to XSR700 wooden binders.

I'm getting my parts list worked up and will pull the trigger on this asap.

Thank you MK, you are the moto man with the plan

[klx678]

It was just plain interesting.  Sometimes I just have to know and this was one of those times.   

 

 

[Pursuvant]

Reading up so I can proof the recommendation of the Brembo Rep Lavash to use 17RCS for the XSR7 (we might be very close to the step up to 19RCS to prevent a soft lever), thought this is interesting

 

Quote

 

19RCS , 17RCS, 15RCS, 14RCS ? These numbers identify piston diameter:

19RCS to be installed on twin disks bikes with axial or radial calipers but NOT on Floating Calipers

17RCS to be installed on twin disks bikes with axial or radial calipers whose pistons diameter is 32mm or lower, but NOT on Floating Calipers; for example Ducati Panigale or RSV4, Yamaha R6 etc etc.

15RCS to be used on twin disks braking system carrying floating calipers (Naked), and on single disk bikes (motard).
The 15 RCS with 15 x 20 set up works like a 16 x 18 mc, while 15 x 18 equals a 16 x 16 mc.

14RCS to be installed on single/twin disks Scooters and single disks Motorcycles (from 50cc up to 600cc) . Available both Right and Left Side.

 

If the xxRCS piston is larger than the OEM stock master cyl, then Brembo says about fitment "Not on Floating Calipers".  That's a curiosity...

 

 

 

 

 

[seven]

On 8/6/2020 at 8:44 AM, Pursuvant said:

Reading up so I can proof the recommendation of the Brembo Rep Lavash to use 17RCS for the XSR7 (we might be very close to the step up to 19RCS to prevent a soft lever), thought this is interesting

On 8/6/2020 at 8:44 AM, Pursuvant said:

19RCS , 17RCS, 15RCS, 14RCS ? These numbers identify piston diameter:

19RCS to be installed on twin disks bikes with axial or radial calipers but NOT on Floating Calipers

17RCS to be installed on twin disks bikes with axial or radial calipers whose pistons diameter is 32mm or lower, but NOT on Floating Calipers; for example Ducati Panigale or RSV4, Yamaha R6 etc etc.

15RCS to be used on twin disks braking system carrying floating calipers (Naked), and on single disk bikes (motard).
The 15 RCS with 15 x 20 set up works like a 16 x 18 mc, while 15 x 18 equals a 16 x 16 mc.

14RCS to be installed on single/twin disks Scooters and single disks Motorcycles (from 50cc up to 600cc) . Available both Right and Left Side.

 

If the xxRCS piston is larger than the OEM stock master cyl, then Brembo says about fitment "Not on Floating Calipers".  That's a curiosity...

 

So does this mean the 19RCS can be installed on the 2019 MT-07?

[stickshift]

4 hours ago, seven said:

So does this mean the 19RCS can be installed on the 2019 MT-07?

17RCS is the recommended size.

[Pursuvant]

13 hours ago, seven said:

So does this mean the 19RCS can be installed on the 2019 MT-07?

Seven, interesting question. You could oversize by using 19RCS but you would be removing feedback from the lever, the opposite of what you said you want to accomplish and what I'm after as well.

Trick is to only step up from stock master cylinder piston size a small amount. By keeping the piston only slightly larger you get enough modulation between the piston increase and RCS piston leverage to have a sweet spot in your final settings. The best available initial  bite without overpowering lever feedback.

Brembo has said clearly go with 17RCS on 2019 XSR700 - if your front caliper pucks are the same size then you should be good.

One note, looks like you already switched to sintered pads. Good move, most will find a solid increase in braking from just those pads. Maybe save your money and use it on those pogo stick front forks. You slow/cure the fork brake diving and that will feel like you've made your brakes much better.

 

[klx678]

I think Brembo is making up for the larger (17 vs 14mm) pistons through the mechanical  advantage of their lever set up of their product versus the stock set up.  Otherwise it would require a smaller piston with the same mechanical advantage of the lever.  That is why they recommend the 17mm on a bike that has been running a 14 like the XSR and I think also the MT-07 are running.  

It's all about leverage, both hydraulic and mechanical.

[mossrider]

15 hours ago, seven said:

So does this mean the 19RCS can be installed on the 2019 MT-07?

Here's what I've learned after extensive testing (and more than a fair amount of monkeying around). More is not always better and just because a person can doesn't mean they should. 

The 19RCS master certainly works on our bikes but is not a good choice on the street, especially when paired with uprated brake lines and pads. It's real easy to develop more stopping power than the stock machine can handle. Without upgraded suspension to stop the rocking horse under heavy braking and to control the weight transfer while slowing and without a good set of tires and without a good road surface under you a person runs a high risk of throwing it down the road or going over the handlebars. Some use it on their race bikes but one must understand that racers run sticky tires, know what lies ahead, they know when, where and how much they are going to brake, there is no turning traffic, no pets or wild animals, no children darting about, no cell phones etc, and all the idiots are going the same direction at the same relative speed, presumably  paying close attention to the task at hand.  The 19RCS offers one finger stopping power, sure, but it comes with caveats. The initial bite and power are ferocious at the expense of feel and a very narrow range of modulation. On the street if you get surprised or panic and mash the brake, as is commonly done, you're toast with the 19. I use 2 fingers on my buddies bike and have to be SO careful, my buddy uses 1 finger and can stand the bike on its nose. Using more would be suicide. Distraction or panic would be suicide.  Here you can see one installed on a friend's bike. Works very well, but.

The 17 and the stocker are better choices and are close in real world performance. On my race bike I still use the stock master as I find it has more than enough power and feel, especially when paired with braided lines and the EBC EPFA HH pads I use. I actually prefer the stock master as I can use more squeeze force and I find it easier to modulate accurately and get good feedback thru the lever with a useful range for modulation. Two finger stoppies are still stone simple. I also leave the heat shields off the back of the pads so they'll transfer heat more directly into the calipers and ultimately the Motul 600 fluid I use in place of the stock DOT stuff.  More aggreesive pads, tho ok on track, arent so good on the street. More aggressive pads need race slicks and heat to funtion properly and arent reliable in the rain. This setup has been good enough for MotoAmerica pace under faster racers than I and is still usable in the wet which can be super dicey with the 19 mega brakes like above. In the rain on the street you'd be better off afoot because you'd soon be there anyway, 

Nearing apex, deep into the forks, two fingered bliss. Stock master, CRG lever, EBC EPFA pads, Motul 600 fluid, Spiegler braided lines. 

Choose wisely.

[seven]

1 hour ago, mossrider said:

Here's what I've learned after extensive testing (and more than a fair amount of monkeying around). More is not always better and just because a person can doesn't mean they should. 

The 19RCS master certainly works on our bikes but is not a good choice on the street, especially when paired with uprated brake lines and pads. It's real easy to develop more stopping power than the stock machine can handle. Without upgraded suspension to stop the rocking horse under heavy braking and to control the weight transfer while slowing and without a good set of tires and without a good road surface under you a person runs a high risk of throwing it down the road or going over the handlebars. Some use it on their race bikes but one must understand that racers run sticky tires, know what lies ahead, they know when, where and how much they are going to brake, there is no turning traffic, no pets or wild animals, no children darting about, no cell phones etc, and all the idiots are going the same direction at the same relative speed, presumably  paying close attention to the task at hand.  The 19RCS offers one finger stopping power, sure, but it comes with caveats. The initial bite and power are ferocious at the expense of feel and a very narrow range of modulation. On the street if you get surprised or panic and mash the brake, as is commonly done, you're toast with the 19. I use 2 fingers on my buddies bike and have to be SO careful, my buddy uses 1 finger and can stand the bike on its nose. Using more would be suicide. Distraction or panic would be suicide.  Here you can see one installed on a friend's bike. Works very well, but.

The 17 and the stocker are better choices and are close in real world performance. On my race bike I still use the stock master as I find it has more than enough power and feel, especially when paired with braided lines and the EBC EPFA HH pads I use. I actually prefer the stock master as I can use more squeeze force and I find it easier to modulate accurately and get good feedback thru the lever with a useful range for modulation. Two finger stoppies are still stone simple. I also leave the heat shields off the back of the pads so they'll transfer heat more directly into the calipers and ultimately the Motul 600 fluid I use in place of the stock DOT stuff.  More aggreesive pads, tho ok on track, arent so good on the street. More aggressive pads need race slicks and heat to funtion properly and arent reliable in the rain. This setup has been good enough for MotoAmerica pace under faster racers than I and is still usable in the wet which can be super dicey with the 19 mega brakes like above. In the rain on the street you'd be better off afoot because you'd soon be there anyway, 

Nearing apex, deep into the forks, two fingered bliss. Stock master, CRG lever, EBC EPFA pads, Motul 600 fluid, Spiegler braided lines. 

Choose wisely.

Thanks for the detailed reply. My question about the 19RCS was mostly born out of reading a post here that said it was no good for the MT-07, but then seeing the 19RCS listed on a website as an upgrade for the MT-07 and then seeing it in the list above I figured I would ask. I totally agree with the sentiment of just because you can, doesn't mean you should.

I am going to start with fluid, lines and pads. I suspect for my purposes the regular EBC HH would be more than sufficient (compared to the EBC EPFA HH pads you run). Also looking at the CL Brakes XBK5/RX3 pads.

After that I want to look at a cost effective suspension upgrade. I am considering at a minimum doing the Dave Moss modification...but that is a topic for another thread.

[Pursuvant]

14 hours ago, mossrider said:

The 17 and the stocker are better choices and are close in real world performance

Nearing apex, deep into the forks, two fingered bliss. Stock master, CRG lever, EBC EPFA pads, Motul 600 fluid, Spiegler braided lines. 

Choose wisely.

Moss, you don't know how much appreciated your experience and brainpower is to the rest of us. I can't be sure of some engineering decisions I'm working because reasons are affecting my physical, and that's why I use the help of my friends offline and new friends here online, to triple check my thinking, to look for mistakes before I make them.

If I were not losing power in my hand to disability, I would not be using that RCS pivot lever. Like you say, I always got what I needed out of the stock oem master cyclinders (after they got the full, twin dedicated ss braided brake lines all the way from MC to Calipers, and the right street pads).

To be clear, I am not recommending anyone use the Brembo RCS. Just the opposite, like all my modifications, THEY CAUSE FOOT FUNGUS. AND YOU COULD GET HARMED.

Thanks amigo from all of us, for jumping into conversations at just the right moment to save many of us money and under-performance from poor engineering decisions.

And nice pic of how trail braking is supposed to be, all the way to the apex!

 

Edited August 28, 2020 by Pursuvant
trail braking

[mossrider]

54 minutes ago, Pursuvant said:

And nice pic of how trail braking is supposed to be, all the way to the apex!

Thanks, Its a staged shot, I cropped the bucket out of the pic I was propped on.

...it takes a real talented fool to dream up a mistake I haven't already tested...