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Discussion Starter #1
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
ModAA.jpg


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
ModBB.jpg


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
ModCC.jpg


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.
 

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I'm not sure if what's really happening is you're pulling our legs or not but if you're really serious about the braking ability of the XSR700, you might consider just slowing down. I think the XSR 700 has good to very good braking for any street use, probably as good as any bikes I've owned including my FZ1 and GPZ900R.
 

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He is serious and it isn't that simple. We have already been in discussion on the topic of master cylinder size and I've been in contact with Brembo, but only on sizing, not on adaptability to the ABS.

If you have ever encountered what is termed a "wooden" brake you would understand. I have. The 1975 Guzzi I rode had what apparently was a dual caliper master cylinder working the single caliper brake. the hydraulic ratio was so low the brake lever moved about 1/8 the way to the handlebar and you needed the grip of the Hulk to squeeze for any good braking. Taking that knowledge in hand, one learns what needs to be done to adapt braking systems. I adapted all three calipers on a Gold Wing side car set up to work using only the hand lever, for a paraplegic rider to ride again.

This member has a disease weakening his grip, he is losing power and needs to up the brake system leverage via the cylinder ratios and the lever leverage to gain back what he is losing.

Now a problem crops up with the ABS. Something I am not familiar with, but have some thoughts.


Pursuvant,
Even with a master cylinder size change the following remains constant:
  • Tthe 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.

I might recommend you take this over to the FZ-07 forum as well. There may have been riders there who have already swapped out for the Brembo. I know there is at least one using the Suzuki radial master cylinder, which ever brand it is.

You may want to see if you can get with a very knowledgeable fluid power engineer, possibly a professor that teaches fluid power at some university may be of help.
 

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i dont want to be daft but maybe he should get a Kawasaki Z900rs if the brakes have way better feel and a lighter unit.
 

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So why doesn't everyone here go buy a faster bike instead of hopping up the one they have?

It's about helping someone do something they want with the bike they want.
 

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sorry, I love my xsr700. I'd be perfectly fine with a Z900rs. I think the brakes are better and far easier to upgrade. It's just another option, considering the RS can be had for not much more than a 700 for leftover. Personally I have a certain dollar amount in upgrades I would not go over, otherwise I'd get a Z.
 

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Discussion Starter #7
Z900rs It's just another option
Thx D, but I picked the XSR7 because 75hp, 50 ft-lbs torque, and 410 lbs.

It's like riding a dirt bike on asphalt, nimble, feels light, and is physically light. I can't upsize to a big gulp
 

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@Pursuvant , hi, I think you made me sit up during your introduction already. I did not react, due it's not my favorite hobby to discuss somebodies disease on a public platform.

Anyhow, what I wanted to say, forget the one finger actuating of the levers. Always use all available fingers to save power and endure all the day riding. It is not a moto cross or stunt bike event, that you need one finger braking. Force and control get better, when you train to use all fingers at your lever. If they do not operate the lever, all fingers are placed around your grips.

Regarding a better front brake, I have my own little story. Some of it is written in my introduction thread. But to make it short, jep, there is a kind of wooden fealing, or as I said, squeezing a wet bread. No defined point, no real increase in break power. But this is not the OEM brake lines only, or the ABS, it is the complete sum of the used components. But my real concern was the moving break point, getting weak on brake, during ambitious twisties riding.

I changed the OEM brake lines against these stainless steel braided lines, which would follow your Mod. C. The result was very disappointing, the improvement was close to zero. Only good thing, you can buy ready to install tailored line kits. I did not search for an option like Mod. B, but as I remember company HEL is offering something. Take note, that MT kits are shorter than XSR kits.

I changed the brake pads twice and ended with Braking P50 sinter, in my opinion very clear initial bite and progressiv increase in brake power.

The brain monkey with an other master cylinder you should follow up, when your hand power will decrease in the future. I see no reason, why a master cylinder shall have impact to the ABS module. But most cylinders will need more hand power or they gain control by more lever travel. Only the high costy products have an adjustable lever arm.

BR
hombacher
 

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Discussion Starter #9
@Pursuvant , forget the one finger actuating of the levers
I was taught early 2 finger clutch and 1 finger brakes, and to always cover the clutch & brake with those fingers. I don't know any other way

But I will save your realistic advice for when I run out of engineering work arounds thank you.

I'm going to rip out those solid brake lines and rubber hose (the solid lines have a smaller ID than rubber or braided lines) and re-plumb everything with ss braided hose from master thru ABS thru calipers, no rubber hose and no small ID solid brake lines the factory used. Already got sintered pads.

Isolate that ABS so I can prove to myself that it's the ABS that's the cause of those wooden feeling brakes. Most people say that's the problem with ABS, I'm going to prove it to myself just because it's an interesting problem to work.

Thx hombacher
 

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To add to the conversation, that is why the Brembo 17 RSV, it has dual pivot position and can add power partly due to pivot position. It will take a bit more travel in doing so, but was the recommended replacement for the master cylinder on the XSR700 by Brembo's designated U.S. representative distributor.

Pursuvant got in touch with me because of some information I had on brake conversions and he's looking for input to decide what path to take. I have to tell you I think he's enjoying the challenge and I'm getting a bit of a kick from being involved a bit in it.

He, much like me and others here, just plain like the bike. So there is really no substitute for it. Let's face it, if it was all about money spent we'd all be riding an FZ or MT-07. They could be had for near $1000 less. But that wasn't what I wanted. Plus a lot of people like to play with the bikes, even knowing they may not get all their investment back. It's just fun. I saw that in one member's wanting to sell theirs, saying they did everything they could and now it's time to do something else, I think they mentioned the 900.

So any knowledgeable hydraulics guys chime in.
 

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Discussion Starter #11
I have to tell you I think he's enjoying the challenge and I'm getting a bit of a kick from being involved a bit in it.
It's the best part of motoworld, working the clever mods. Here's my last sick ride before the XSR, about 40 published mods on the road star warriors website, made it in their Yamaha calendar. Now that was some sick fun right there!

24748
 

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Reply from Brembo's rep says no problem:

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

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I'm still not convinced by your approach.

One real weak point of the 700's front brake are the OEM pads. They last for many ten thousand miles, but do not wear. So first attempt, easy and quick to perform, cheap and in its result easy to proof. Go and chose a more aggressive set of brake pads.

Second would be, change the tires. The Pirelli Sports Comp are nice, but easier handling, better braking performance will come with a proper set of actual touring sports.
The other gain on the good side, the ABS at the front will come much, much later, when braking in the bumpy 'brake' zone of crossings, for example.
This said, the ABS is not a real weak point of the brake. It is not the best, in means of a budget system, but it works properly in my opinion and after my mods, there was no reason to complain. Or the other way round, the XSR ABS is not a reason, that you have a weak brake performance or a woody feel on brake.

You can swap to stainless steel braided lines, but it will change not anything.

The master cylinder, already mentioned above, be sure, what you are doing. The OEM one is a 15 mm piston, if I follow the number given on the master cylinder housing. The mentioned Brembo RCS 17 x 18-20 will have a 17 mm piston. Bigger piston means higher hand force, but less stroke, additionally you can switch the stroke at the RCS.

But hey, your initial wish was a lower hand force.

Only hope which may come true, that a radial master cylinder can not be compared one to one with the OEM cylinder. It can be possible, that the leverage ratio radial to OEM is beneficial towards a reduced hand power. But who knows? With the 17 mm bigger piston, the force to the brake calipers will increase. But then we are at the beginning again. The OEM pads are the weak point and produce a vague point of initial braking. With just a higher force, nothing is won or will be better.

Some say the RCS are 'single-use' masters, because Brembo offers no spare parts kit. Some recommend the Magura HC-1 or GaleSpeed VCR, which as well offer a wire clutch perch kit, incl. variable lever ratio.
 

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I'm still not convinced by your approach.

One real weak point of the 700's front brake are the OEM pads. They last for many ten thousand miles, but do not wear. So first attempt, easy and quick to perform, cheap and in its result easy to proof. Go and chose a more aggressive set of brake pads.

Second would be, change the tires. The Pirelli Sports Comp are nice, but easier handling, better braking performance will come with a proper set of actual touring sports.
The other gain on the good side, the ABS at the front will come much, much later, when braking in the bumpy 'brake' zone of crossings, for example.
This said, the ABS is not a real weak point of the brake. It is not the best, in means of a budget system, but it works properly in my opinion and after my mods, there was no reason to complain. Or the other way round, the XSR ABS is not a reason, that you have a weak brake performance or a woody feel on brake.

You can swap to stainless steel braided lines, but it will change not anything.

The master cylinder, already mentioned above, be sure, what you are doing. The OEM one is a 15 mm piston, if I follow the number given on the master cylinder housing. The mentioned Brembo RCS 17 x 18-20 will have a 17 mm piston. Bigger piston means higher hand force, but less stroke, additionally you can switch the stroke at the RCS.

But hey, your initial wish was a lower hand force.

Only hope which may come true, that a radial master cylinder can not be compared one to one with the OEM cylinder. It can be possible, that the leverage ratio radial to OEM is beneficial towards a reduced hand power. But who knows? With the 17 mm bigger piston, the force to the brake calipers will increase. But then we are at the beginning again. The OEM pads are the weak point and produce a vague point of initial braking. With just a higher force, nothing is won or will be better.

Some say the RCS are 'single-use' masters, because Brembo offers no spare parts kit. Some recommend the Magura HC-1 or GaleSpeed VCR, which as well offer a wire clutch perch kit, incl. variable lever ratio.
What break pads do you recommend for the front and back?
 

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See above:

[..]
I changed the brake pads twice and ended with Braking P50 sinter, in my opinion very clear initial bite and progressiv increase in brake power.
Brembo SA is nice, much better than OEM, as all other sinter pads will do. Such as Lucas or even the branded pads of the big three from HG, Louis or Polo.

But I do not have any suggestion for the rear, I do not use it and it will last for 100 tkm.


How ever, keep in mind the brake will react completely different in the front. It is not a beginner brake any more. It will bite, for some riders, not used of it, it could be already to much brake..
 

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I have a bit of background on our fellow rider, he definitely knows what he is getting into. We had some PMs about it before his posts. Because of that and my interests, I ran with it a bit.

I knew the piston size of the Yamaha brake is 15mm and in contacting Brembo I pointed that out. In return Brembo's rep pointed to the 17mm and they list that as the one for the MT and XSR. I also found the RSC 17mm being listed and used for the FZ and MT by riders, part of the confusing part for me originally. The missing factor was the mechanical leverage of the hand lever on the piston. The Brembo has a higher leverage allowing the bigger piston while maintaining the fluid flow and pressure.

I don't really particularly have a problem with the XSR brake, but realize that's me, not everyone. I am a two-three finger brake operator and don't really find the brake lacking for my use so far. Might change, but I can anchor it down fairly well, still waiting to see when I bump the ABS with the front. But again, that's me and I do not have anything affecting my grip.

I'd be intrigued with the Brembo on the bike, because I have ridden a bike with a powerful enough system to use one finger. The Aprilia SXV 550 supermoto had an insane brake. I never rode a bike that the power of the front brake had me on edge. It was so powerful and the bike so light that it would have taken me a month to adapt to using it efficiently. Usually it is the other way around, insufficient power. Never ever thought I'd ride a bike that could truly put you over the bars by using the front brake - that was it.
 

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But I do not have any suggestion for the rear, I do not use it and it will last for 100 tkm.
You do need to be careful not using the rear brake. Things can get sticky back there.

My former employer/Honda dealer rode a CB900F with the sport control and fairing kit as his "daily driver" not using a car. He nearly never used the rear brake... One day we get a call from him. Seems his bike was sitting out along the road with a locked rear wheel. The rear caliper had crudded up and when the pistons didn't release completely. When the friction of the rotor on the pads heated everything up the rear wheel was sticking. Lesson being use the rear brake frequently enough you don't end up with it seizing just to keep things moving.

I found I actually use the rear brake a lot more now after a couple decades of riding a dual sport doing a lot of dirt/gravel roads. Got in the habit and now it's an automatic. The XSR has the best positioned rear brake lever of any bike I've ridden.
 

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No offence, separate between the old stories and actual layout carefully, please.

Honda CB900F is something from the real past. End of 70s, or already begin of 80s it was offered in the states. I assume due to the age, these were steel casted brake discs, which tended to corrode much faster and heavier than nowadays discs. Pads, pistons, sealings and even the calipers corroded under getting dirty. Cleaning often under dismantling was a task to be done regulary, if commuting daily.

My sunny weather ride can not be compared with that Honda. My actual brake set-up comes close to the described Aprilia. If you are not prepared or have already trained it, you will go over the handle bar in that moment, when you think about braking. The XSR is lightweight and powerful, so it needs some adequate brakes.
 

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What? I was replying to your comment about not using the rear brake, giving some good advice and then a brief story why it makes sense. You can neglect things to the point where they don't work right.

Plus that brake set up is still current. In fact that "old" rear brake on the CB900 was twin piston where the "modern" XSR is a single piston set up. Both are floating caliper as well.

As for the material, been there done that, the same stuff is showing up on bikes now. Brake rotors were stainless, just like now. Seals are still sold, similar chrome pistons. About the only change is a bit thinner rotors.

You must be thinking of the rotors used on Euro bikes, my Moto Guzzi would have a layer of rust if it sat in rain for a day or so. Japanese bikes have had stainless rotors since the first ones showing up on the late 60s bikes like the CB750K0, no rust.

The Advic mono block brakes on the XSR have the same internal parts as used in sport bikes over two decades ago... 1997 R6 and R1 to be exact. Plus they are still the axial mount type rather than the higher tech radial mount type, so hardly cutting edge.

Fact is those twin piston Nissins on the 82 Honda were on a more powerful heavier bike than the XSR and they worked pretty well in spite of not being four piston. Oh, and they were used on the Honda CBR600F through F3 models, as well as the VFR750/700, both over 80 hp and capable of over 135 mph. The bikes weren't all slugs back then.

I made my comment about using the rear brake for everyone, not just for you. Some riders will spray water in around the calipers when cleaning - not a great idea - and the moisture may get inside the calipers, some heat from use may stave off seizure. So it is not a frivolous comment. Kind of reminds me of my old arthritic knees. The more I use them the better they will work and the longer they will last.

It just makes sense to consciously use some rear brake some times. Any time the rear tire is on the ground it can help slow things up and with use comes skill, aka no lock ups.
My rear braking ability came from the dual sport and supermoto play on the back dirt/gravel roads, learning the touch on loose gravel, not to mention intensional lock and slide maneuvers. Takes the touch to not lock on loose surfaces unless I want to and then how much it takes to do what I want. The skill comes in handy to maximize braking on pavement too. I'm kind of surprised I do rear braking as much as I have, another skill that is now virtually automatic. Pre-dual sport I was mainly front brake only on pavement.

If you read what Pursuvant writes you will realize he's no rookie by any means. It is a quite serious discussion for serious minds. I doubt too many rookie beginners will run out and buy $250-300 Brembo RSV17 master cylinders because of the discussion of using them.

So, with your bike, what set up are you using?
 

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See above:



Brembo SA is nice, much better than OEM, as all other sinter pads will do. Such as Lucas or even the branded pads of the big three from HG, Louis or Polo.

But I do not have any suggestion for the rear, I do not use it and it will last for 100 tkm.


How ever, keep in mind the brake will react completely different in the front. It is not a beginner brake any more. It will bite, for some riders, not used of it, it could be already to much brake..
Thanks for the feedback. I read your original post where you mentioned your pads a few days ago but somehow forgot about it.
Thanks also for the heads up about the behaviour change specifically for beginner rides such as myself. I actually find the oem break great; I was just curious and collecting knowledge for a potential change when I can actually benefit from it. Thanks again.
 
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