Aftermarket radial master cylinders - Wrist Twisters
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post #1 of 60 Old 12-06-2010, 01:07 PM Thread Starter
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Aftermarket radial master cylinders

radial master cylinder items - Get great deals on eBay Motors, Brakes Suspension items on eBay.com! Search by Price + shipping: lowest first. There are dozens listed. Most of these are shipped from Thailand, but it's up for grabs where they are made. Anyone care to hazard a guess?

BUT WAIT!!!!!!!! There's more!!!!!

Scrolling down through one MC listing I found amongst the other items available from the seller Brembo (at least from the pictures) 40mm mount four pot calipers for $50 plus shipping. Interestingly, they do not claim they are Brembo units anywhere in the text of the listing, so I wonder if they are using pictures of real Brembos in the ad while not making theirs with the logo, or if they are unashamed counterfeits. Not willing to buy a pair to find out.

Frankly, I'm considering buying a 16 x 18 radial master to see how it works with the 919 OEM calipers. At worst it will be too sensitive, but for $54 or so it would be interesting. BTW, there is also a listing for a Brembo radial master cylinder fitted by Yamaha to the current R1 / R6. While they don't say so in the ad, it's a 16 x 18, not a 19 x 18. It's highest bid is currently $20, but with 5 days left it will certainly go to near the retail price of $180 at closing.

Rob

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post #2 of 60 Old 12-06-2010, 02:18 PM
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I'll be trying one of them, anyone out there tried them already?

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post #3 of 60 Old 12-06-2010, 02:28 PM
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Quote:
Originally Posted by robtharalson View Post
radial master cylinder items - Get great deals on eBay Motors, Brakes Suspension items on eBay.com! Search by Price + shipping: lowest first. There are dozens listed. Most of these are shipped from Thailand, but it's up for grabs where they are made. Anyone care to hazard a guess?

BUT WAIT!!!!!!!! There's more!!!!!

Scrolling down through one MC listing I found amongst the other items available from the seller Brembo (at least from the pictures) 40mm mount four pot calipers for $50 plus shipping. Interestingly, they do not claim they are Brembo units anywhere in the text of the listing, so I wonder if they are using pictures of real Brembos in the ad while not making theirs with the logo, or if they are unashamed counterfeits. Not willing to buy a pair to find out.

Frankly, I'm considering buying a 16 x 18 radial master to see how it works with the 919 OEM calipers. At worst it will be too sensitive, but for $54 or so it would be interesting. BTW, there is also a listing for a Brembo radial master cylinder fitted by Yamaha to the current R1 / R6. While they don't say so in the ad, it's a 16 x 18, not a 19 x 18. It's highest bid is currently $20, but with 5 days left it will certainly go to near the retail price of $180 at closing.

Rob
it will have less stopping power compared to the stock 14mm piston of the stock master.... personally i wouldn't trust a Chinese break component... specially on the front!

also... id much rather just leave the stock master's and calipers and spend the 70 bucks and go with some stainless steel lines.

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post #4 of 60 Old 12-06-2010, 05:48 PM
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Been using the '07 Nissin GSXR radial M/C (19mm) w/ a set of RC51 34/32mm calipers. The combo is awesome.....but, the SP1 RC calipers are designed for a 19mm MC.

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post #5 of 60 Old 12-06-2010, 08:21 PM
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Been using the '07 Nissin GSXR radial M/C (19mm) w/ a set of RC51 34/32mm calipers. The combo is awesome.....but, the SP1 RC calipers are designed for a 19mm MC.
exactly... good quality parts that are ment for eachother.... u can skimp on places like your seat foam, blinkers, headlight... but CRUCIAL stuff like a master cylinder and caliper... ya

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post #6 of 60 Old 12-06-2010, 09:00 PM
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Gotta admit.....Rob's the king of info.....I came up with this combo thanks to some of the info he's posted in the archives......

Figure you have '07 gsxr radial is a 19mm (nissin).....the '08-'09 gsxr radial is a 17mm (nissin).....and the R1/R6 radial is a 16mm. (brembo)

You do the math.....you have 3-4 Nissin caliper piston sizes to choose from.....with the SP1 RC51 & f4I calipers having the largest pistons....both needing 19mm mcs.

SP2 calipers or 954 calipers.....might work with the '08-'09 17mm gsxr radial m/c.

The R1/R6 brembo might be ok with the stocker 919 calipers......

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post #7 of 60 Old 12-06-2010, 09:04 PM
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Btw ---- paid $50 for my RC calipers.....and $70 for my mc. Ended up selling the stocker 919 stuff for more.

The upgrade almost paid for itself if it wasn't for having to buy new Vesrah RC pads.

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post #8 of 60 Old 12-06-2010, 09:13 PM
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Quote:
Originally Posted by robtharalson View Post
radial master cylinder items - Get great deals on eBay Motors, Brakes Suspension items on eBay.com! Search by Price + shipping: lowest first. There are dozens listed. Most of these are shipped from Thailand, but it's up for grabs where they are made. Anyone care to hazard a guess?

BUT WAIT!!!!!!!! There's more!!!!!

Scrolling down through one MC listing I found amongst the other items available from the seller Brembo (at least from the pictures) 40mm mount four pot calipers for $50 plus shipping. Interestingly, they do not claim they are Brembo units anywhere in the text of the listing, so I wonder if they are using pictures of real Brembos in the ad while not making theirs with the logo, or if they are unashamed counterfeits. Not willing to buy a pair to find out.

Frankly, I'm considering buying a 16 x 18 radial master to see how it works with the 919 OEM calipers. At worst it will be too sensitive, but for $54 or so it would be interesting. BTW, there is also a listing for a Brembo radial master cylinder fitted by Yamaha to the current R1 / R6. While they don't say so in the ad, it's a 16 x 18, not a 19 x 18. It's highest bid is currently $20, but with 5 days left it will certainly go to near the retail price of $180 at closing.

Rob
No one has yet to find/test a major upgrade radial m/c with the stock 919 calipers.

Go for it! If it works.....it will pave the way for many future 919'ers.

It's a 16mm Brembo damn-it!

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post #9 of 60 Old 12-06-2010, 09:16 PM Thread Starter
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Quote:
Originally Posted by nd4spdbh View Post
it will have less stopping power compared to the stock 14mm piston of the stock master.... personally i wouldn't trust a Chinese break component... specially on the front!
On the contrary -- if you look at the '05 R1 front brake assembly the dimensions are as follows: caliper pistons of 30mm and 27mm, nearly exactly the same as the 919, and a properly dimensioned master cylinder to supply the proper pressure: a 16 x 18 radial unit. Ergo, the master cylinder will work with the 919 calipers. Why? While the area of the master cylinder is ~ 30% larger than the 919 master, the mechanical ratio is ~ 35% higher. The end result? The overall ratio is ~ 5% greater. Not nearly enough to worry about.

This is one of my specialities, and if I were to purchase one the first order of business would be to tear it down completely and evaluate each part, assembly clearances, material type and quality, and attention to detail with an objective eye. If it meets with my approval I'll put it into service after my usual fettling.

Quote:
also... id much rather just leave the stock master's and calipers and spend the 70 bucks and go with some stainless steel lines.
Been there, done that already. The reasons why I'm doing this are many, but in this case there is a specific puropse -- most naked bikes have the instruments mounted on the upper triple clamp, and therein lies the problem: if you want low and narrow handlebars such as TharBars they are right in the way of the hydraulics, requiring either a manifold as I have already done or an alternative such as this. Of course there is no mirror mount, but with a little creativity ...

Rob

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post #10 of 60 Old 12-06-2010, 09:20 PM
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Lol........ya know, during tough times.....sometimes I question God also....

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post #11 of 60 Old 12-06-2010, 11:00 PM
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Quote:
Originally Posted by robtharalson View Post
On the contrary -- if you look at the '05 R1 front brake assembly the dimensions are as follows: caliper pistons of 30mm and 27mm, nearly exactly the same as the 919, and a properly dimensioned master cylinder to supply the proper pressure: a 16 x 18 radial unit. Ergo, the master cylinder will work with the 919 calipers. Why? While the area of the master cylinder is ~ 30% larger than the 919 master, the mechanical ratio is ~ 35% higher. The end result? The overall ratio is ~ 5% greater. Not nearly enough to worry about.

This is one of my specialities, and if I were to purchase one the first order of business would be to tear it down completely and evaluate each part, assembly clearances, material type and quality, and attention to detail with an objective eye. If it meets with my approval I'll put it into service after my usual fettling.

Been there, done that already. The reasons why I'm doing this are many, but in this case there is a specific puropse -- most naked bikes have the instruments mounted on the upper triple clamp, and therein lies the problem: if you want low and narrow handlebars such as TharBars they are right in the way of the hydraulics, requiring either a manifold as I have already done or an alternative such as this. Of course there is no mirror mount, but with a little creativity ...

Rob
gotcha, go for it n let us know. still.... the thought of a chinese master kinda makes me shudder haha.

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post #12 of 60 Old 12-07-2010, 03:24 AM
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It's funny how those Chinese master cyl have Brembo symbol on them (or something that looks like it)

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post #13 of 60 Old 12-07-2010, 03:37 AM
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gotcha, go for it n let us know. still.... the thought of a chinese master kinda makes me shudder haha.
I cant shake that feeling either, Everytime I read "made in china" my brain automatically replaces that with "shit" may not even be right but thats what happens. (Im assuming they're made in china knock offs)

Rob I'll be interested to see what the results are, I may start looking for its japanese equal. Good work!

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post #14 of 60 Old 12-07-2010, 09:11 AM
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gotcha, go for it n let us know. still.... the thought of a chinese master kinda makes me shudder haha.
......he did mention there are a bunch of Chinese parts out there cheap. But his post says he wants to try the Brembo Radial off the R1. Not a Chinese part at all.....

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post #15 of 60 Old 12-07-2010, 10:07 AM Thread Starter
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......he did mention there are a bunch of Chinese parts out there cheap. But his post says he wants to try the Brembo Radial off the R1. Not a Chinese part at all.....
That's the assumption, but in today's market who knows? Never assume.

Rob

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post #16 of 60 Old 12-07-2010, 10:36 AM
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ya it definitely depends on where you get the Chinese part from... i have bought some Chinese stuff that was pretty damn good quality... other stuff not so much.

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post #17 of 60 Old 12-07-2010, 10:59 AM
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ya it definitely depends on where you get the Chinese part from... i have bought some Chinese stuff that was pretty damn good quality... other stuff not so much.
In our business, we find one of two extremes and nothing in the middle.
Very good or very bad.

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post #18 of 60 Old 12-12-2010, 02:20 PM Thread Starter
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Quote:
Originally Posted by nd4spdbh View Post
ya it definitely depends on where you get the Chinese part from... i have bought some Chinese stuff that was pretty damn good quality... other stuff not so much.
Quote:
Originally Posted by mcromo44 View Post
In our business, we find one of two extremes and nothing in the middle.
Very good or very bad.
Here's hoping it falls on the good side of the specrum. A teardown will tell.

DUCATI KTM Brake 16x18 Radial pump Master Cylinder Kits - eBay (item 320626665775 end time Dec-09-10 19:54:16 PST) ordered. Pretty much selected at random -- and for $10 + it's not a big risk either way.

I'll keep you posted.

Rob

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post #19 of 60 Old 12-17-2010, 11:39 AM
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....... update?

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post #20 of 60 Old 12-17-2010, 01:05 PM
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....... update?
I ordered one, shipping is 7-21 days... still waiting

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post #21 of 60 Old 12-17-2010, 01:51 PM Thread Starter
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....... update?
............ Still waiting for the master. Stay tuned.

Rob

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post #22 of 60 Old 12-17-2010, 01:57 PM
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............ Still waiting for the master. Stay tuned.

Rob
stuff from china has been takin me about 10-12 days including weekends sometimes more.

Ordered two things recently on the 5th and they got here yesterday.

Round the holidays customs gets a lil busy n backed up.

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post #23 of 60 Old 12-17-2010, 04:26 PM
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Yeah....your right.... sometimes their mail system gets a little tired.


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post #24 of 60 Old 12-17-2010, 04:40 PM
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Yeah....your right.... sometimes their mail system gets a little tired.

lol its not their mail system... its when it hits customs here at the us.

mid summer when customs is at a very light load i had mirrors shipped from china to me in 3 days via standard shipping.

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post #25 of 60 Old 12-17-2010, 05:59 PM
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Anyone knows where I can find 13mm radial master?

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post #26 of 60 Old 12-18-2010, 06:03 AM Thread Starter
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Anyone knows where I can find 13mm radial master?
There are some available, but they are expensive (in the $240 to $420 range). As far as I know the only manufacturer of 13mm radials is Magura.
Phat Performance Parts - Motorcycle Parts and Motorcycle Accessories
-------------or-------------------
Magura Radial Master Cylinder 13mm LH 195 , Magura at NAARDEN SPORTBIKE ONLINE STORE
They also have 11, 12, 16, and 20mm units as well.

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post #27 of 60 Old 12-20-2010, 03:20 AM
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Question for you guys:

I have stock 1/2 master on my DRZ400SM (12.7mm in the manual). Is there any benefit in switching to 12mm radial master? Or it will be a loss due to it being 0.7mm smaller? I was looking for 13 mm radial but have an opportunity to grab 12mm for 1/2 off

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post #28 of 60 Old 12-20-2010, 06:21 AM
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Question for you guys:

I have stock 1/2 master on my DRZ400SM (12.7mm in the manual). Is there any benefit in switching to 12mm radial master? Or it will be a loss due to it being 0.7mm smaller? I was looking for 13 mm radial but have an opportunity to grab 12mm for 1/2 off
zaq, you will lose 10.7 % piston area going from a 12.7 down to a 12.
I think that would be OK, but you would be able to feel it. See if you can figure out the total leverage ratio, which is the number that will tell the whole story.
Can you find out what the Interaxis Distance is on the radial you are looking at to buy ?
My guess is that the 12, after lever ratios and therefore lever stroke are accounted for, you'll end up needing a bit less effort but using up more travel, while having a bit better feel from the advantage of the radial.

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post #29 of 60 Old 12-20-2010, 07:08 AM
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Thanks mcromo.
It's Magura 195 master. I'm not sure on the pivot distance, 20mm? Where can I find this info?


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zaq, you will lose 10.7 % piston area going from a 12.7 down to a 12.
I think that would be OK, but you would be able to feel it. See if you can figure out the total leverage ratio, which is the number that will tell the whole story.
Can you find out what the Interaxis Distance is on the radial you are looking at to buy ?
My guess is that the 12, after lever ratios and therefore lever stroke are accounted for, you'll end up needing a bit less effort but using up more travel, while having a bit better feel from the advantage of the radial.

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post #30 of 60 Old 12-20-2010, 07:50 AM
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Thanks mcromo.
It's Magura 195 master. I'm not sure on the pivot distance, 20mm? Where can I find this info?
1
Try asking the seller to measure it for you.
You may have to give decent instructions.

2
No doubt you did the same quick search on them as I just did.
Lots of talk about optimized distance but no specs.
I'm assuming Magura has a "contact" feature on their website.
You might be able to get through to them that way with a tech question.
Or try an on line seller on the basis that you can't decide on the diameter without also knowing the distance.

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post #31 of 60 Old 12-21-2010, 04:30 AM
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Probably silly question but...........

do you guys think it is possible just to swap piston assembly to increase the size or the whole radial master housing needs to be changed?
Let's say if you get 12mm master and then get 13mm piston assembly, would it work or the housing bore is specific for each piston size?

I don't have a cross section view of Magura 195. All I have is this pic of the piston. Is there anything else between the piston and housing bore? Could it be that housing is made for the biggest piston and than there is some kind of spacer which dictates the piston size?


Attachment 15823

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post #32 of 60 Old 12-21-2010, 06:52 AM
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Probably silly question but...........

do you guys think it is possible just to swap piston assembly to increase the size or the whole radial master housing needs to be changed?
Let's say if you get 12mm master and then get 13mm piston assembly, would it work or the housing bore is specific for each piston size?

I don't have a cross section view of Magura 195. All I have is this pic of the piston. Is there anything else between the piston and housing bore? Could it be that housing is made for the biggest piston and than there is some kind of spacer which dictates the piston size?


Attachment 15823
Mr Tharlson is THE one to answer this.

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post #33 of 60 Old 12-21-2010, 09:58 AM Thread Starter
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A master cylinder is the same as any other cylinder in that it is bored to function with a particular piston and seals. Just like an engine it would be necessary to bore it out for a larger piston, with particular attention paid to the surface finish (<20 RMS) for seal longevity and life. It's definitely not a job for the average shade tree mechanic. Commonly, the manufacturers will produce a single casting that can be bored to (say) a range of 11 to 14 mm, greatly simplifying their inventory tracking, but this doesn't make the end user's life any simpler.

It is, however, comparatively simple to change the mechanical component of the overall ratio by moving the master cylinder toward or away from the right grip -- in other words, change where your fingers(s) apply force to the lever. The further away the greater the ratio. Too sensitive? move the master toward the end of the bar and it will take more force at the lever to apply the brakes. It's really that simple. Well, that is as long as there is room to move things.

An illustration: with the stock components the 919's overall ratio is 103:1, but if you move the master away from the throttle by 10mm the ratio goes to 116:1 -- a significant change.

The lesson here is there's more than one way to arrive at a desired configuration.

Rob

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post #34 of 60 Old 12-21-2010, 11:43 AM
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Originally Posted by robtharalson View Post
A master cylinder is the same as any other cylinder in that it is bored to function with a particular piston and seals. Just like an engine it would be necessary to bore it out for a larger piston, with particular attention paid to the surface finish (<20 RMS) for seal longevity and life. It's definitely not a job for the average shade tree mechanic. Commonly, the manufacturers will produce a single casting that can be bored to (say) a range of 11 to 14 mm, greatly simplifying their inventory tracking, but this doesn't make the end user's life any simpler.


Rob
Rob,

Even even more critical than the bore job would be the circlip groove for assembly retention.

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post #35 of 60 Old 12-21-2010, 11:50 AM
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Originally Posted by robtharalson View Post
It is, however, comparatively simple to change the mechanical component of the overall ratio by moving the master cylinder toward or away from the right grip -- in other words, change where your fingers(s) apply force to the lever. The further away the greater the ratio. Too sensitive? move the master toward the end of the bar and it will take more force at the lever to apply the brakes. It's really that simple. Well, that is as long as there is room to move things.

An illustration: with the stock components the 919's overall ratio is 103:1, but if you move the master away from the throttle by 10mm the ratio goes to 116:1 -- a significant change.



Rob


This a real good point.
Just one thing though, the above is a legit and easy method to use, as long as one is not trying to compensate for excessive lever travel for any given amount of braking force applied at the wheel.
The thing to keep in mind that by virtue of the master piston moving, displacement is occurring, so as master piston diameter decreases, the stroke has to increase in order to maintain the same volumetric displacement.
The theoretical hydraulic non compressible fluid regime only begins after the pad clearance is gone and the pads are starting to load up on the rotors.

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post #36 of 60 Old 12-21-2010, 01:13 PM Thread Starter
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Quote:
Originally Posted by robtharalson View Post
............ Still waiting for the master. Stay tuned.

Rob
Ordered on the 13th, got it on the 20th. Remarkable, considering it had to go through the customs and Homeland Security gantlets. As to the shipping charges, they were stated as $32, but the postage on the box says 349 Thai Baht, the equivalent of $11.58 USD, meaning the master actually cost $30.38, still quite a bargain.

The master body is a permament die casting with a body diameter (29mm)suitable for 16mm or 19mm, and is a bit rough around the edges finish wise, but a file test shows the aluminum to be roughly the equivalent of 6061 - T5 or so, something that was worrying me when I ordered it. As it is it shouldn't be a problem. The action moves quite smoothly and has no unusual angles in it, though it will need some adjustment to place the geometry at the right angle "sweet spot" corresponding to the brake actuation point. It's all part of fettling needed even for a Brembo unit.

As to the teardown: I'm in the throes of making a suitable internal ring spanner to remove the end retaining ring in order to get the piston out to inspect the bore / seals / whatever else I find in there.

In the meantime I'm considering the alternatives to adapt the 10mm x 1.0 (darn it) outlet thread to two -3 AN fittings -- fortunately it's a cinch to thread 10mm x 1.0 to 1/8th pipe, something I've been doing for over 30 years and hundreds of units without a single problem. It looks like I'll either use the existing manifold in use at the moment or adapting a brass 1/8th pipe male to two 1/8th pipe female street tee, then thread the right angle 1/8th pipe to -3 male fittings. I also have a tremendous number of -3 AN reusable fittings, so I'll tiptoe through them and see what I can come up with. See the last two pictures.

When they said it was for single caliper applications only they aren't kidding -- the reservoir only holds a maximum of 21 cc's, suitable for the fluid displaced into one four pot caliper, but not for the 919 calipers which require at least 31 cc's for sufficient supply for the entire wear of the pads. No problemo for me as I have several alternative reservoirs to choose from, but for anyone else ... plan accordingly. That and the 10mm x 1.0 thread banjo bolt you'll need to hook it up. I'll check for masters threaded 10mm x 1.25 and get back to you.

The only other problem is rigging a brake light switch: there is no provision for mounting it at all, so I'll have to take a scrap of aluminum stock and whittle out a mount pad for a standard microswitch, epoxy it to the master, and figure out some way to actuate it. All part of the job, and no great problem. If / when I get it finalized I'll offer it for sale to anyone considering this modification. Should be interesting.

Anyway, it looks like I'll have it hooked up and bled in a couple days and have some word as to the feel. That is if it ever stops raining -- the last thing I want to do is test a different setup under anything but ideal conditions! Go ahead, call me a coward.

Rob
Attached Images
File Type: jpg Brembo knockoff 1.JPG (179.2 KB, 8 views)
File Type: jpg Brembo knockoff 2.JPG (168.2 KB, 6 views)
File Type: jpg Brembo knockoff 3.JPG (176.7 KB, 7 views)
File Type: jpg Brembo knockoff 4.JPG (189.2 KB, 6 views)
File Type: jpg Manifold 1.JPG (180.4 KB, 6 views)
File Type: jpg Manifold 2.jpg (45.7 KB, 5 views)

If it has already been done, it is safe to assume it is possible to do it.
On the other hand, if it has not been done never assume it is impossible to do it.
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post #37 of 60 Old 12-21-2010, 01:33 PM
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Quote:
Originally Posted by robtharalson View Post
When they said it was for single caliper applications only they aren't kidding -- the reservoir only holds a maximum of 21 cc's, suitable for the fluid displaced into one four pot caliper, but not for the 919 calipers which require at least 31 cc's for sufficient supply for the entire wear of the pads. No problemo for me as I have several alternative reservoirs to choose from, but for anyone else ... plan accordingly. That and the 10mm x 1.0 thread banjo bolt you'll need to hook it up. I'll check for masters threaded 10mm x 1.25 and get back to you.
Rob
So for the 919 you just need a bigger reservoir and a banjo bolt? Got any I can take off your hands?

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so it will need 10x1 banjo?

would something like this work?

Pegasus - Banjo Bolt, 10 x 1.0mm Double Banjo

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Quote:
Originally Posted by mcromo44 View Post
Rob,

Even even more critical than the bore job would be the circlip groove for assembly retention.
Of course. That's why this is not a job for the machine tool challenged. At any rate, if you have the necessary machines and tooling to do this you could easily make a master cylinder body from billet that would work with a suitable piston assembly. It all depends on your resources and knowledge.
Quote:
Originally Posted by mcromo44 View Post
This a real good point.
Just one thing though, the above is a legit and easy method to use, as long as one is not trying to compensate for excessive lever travel for any given amount of braking force applied at the wheel.
The thing to keep in mind that by virtue of the master piston moving, displacement is occurring, so as master piston diameter decreases, the stroke has to increase in order to maintain the same volumetric displacement.
The theoretical hydraulic non compressible fluid regime only begins after the pad clearance is gone and the pads are starting to load up on the rotors.
Good point. In general I go for a master cylinder piston a bit larger than is fitted stock and make adjustments to the mechanical end of things to get the feel right. This is the sine qua non of radial master cylinders -- too big a piston pushed by a greater mechanical ratio, resulting in a rough approximation of the original ratio, or whatever change you are looking for. In point of fact the mechanical end of things is the only real adjustment possible for the average end user.

By the way, here's the formula I use to determine the overall ratio. Notice I'm not doing the PI * Radius squared for the diameters ... all that is needed is to square the diameters to get an accurate result.

Ratio = (1/MCD^2)*((LP^2 + MiP^2 + SP^2)*NP)*(PTF / PTP)
Where:
MCD = Diameter of the master cylinder piston.
LP = Diameter of the largest piston.
MiP = Diameter of the smaller piston. If you're not working out a four piston caliper equate to zero.
SP = Diameter of the smallest piston. If you're not working out a six piston caliper equate to zero.
NP = The number of only one diameter piston. Ex.: for a two caliper setup NP = 4 (four largest pistons)
PTF = Distance from the lever pivot to the point where your fingers rest on it. If using multiple fingers arbitrarily equate to the mean center of all fingers.
PTP = Distance from the lever pivot to the piston. Usually specified by the manufacturer.
Be sure to keep all measurements in the same units. I always use millimeters, but it will work in inches ... or miles if you prefer.

If you are working out a single acting caliper remember there are actually two faces the pressure bears against: the piston and the back of the bore it is housed in. This side pushes the mobile part of the caliper in the opposite direction as the piston(s), applying force to the inside pad(s). NP will be the same as if you were working out a double acting caliper.

FYI, I usually shoot for an overall ratio in the neighborhood of 100:1. This can be adjusted up or down to suit your preferences and to compensate for softer (sticky) or harder (slippery) pads.


Rob

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Quote:
Originally Posted by aciarrocc View Post
So for the 919 you just need a bigger reservoir and a banjo bolt? Got any I can take off your hands?
I might have an extra reservoir you could have for the cost of shipping, but you're on your own for the banjo bolt. They're usually available at any brake supply business -- it's a common pitch used by cars with iron master cylinders.
Quote:
Originally Posted by zaq123 View Post
so it will need 10x1 banjo?
would something like this work?
Pegasus - Banjo Bolt, 10 x 1.0mm Double Banjo
Yup, that is as long as you are running two lines from the master cylinder.

Again, I'll keep you posted about the brake light switch. If you want there are pressure switches built into a banjo bolt that will work, but I'm not anxious to introduce another failure point if I have an alternative -- I have seen them fail.

Rob

If it has already been done, it is safe to assume it is possible to do it.
On the other hand, if it has not been done never assume it is impossible to do it.
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