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Discussion Starter #1 (Edited)
I'm a curios fellow, and I like figuring things out, but I am stumped. I mean, I have a guess, but you guys must have the real answer. Nothing important here, just curiosity getting the better of me.

I have noticed that on many bikes, including Troy Bayliss'ss'ss Ducati and Rossi's M1 there exists an interesting peculiarity...After looking at Moto Corse's Platino, there it is again, I have to ask...

Why is the front brake master cylinder a cast unit, and the clutch master cylinder a billet item? (These are all Brembo examples, I believe)

My only guess, and it is just that; cast dissipates heat better and is required on the brake side due to higher temp?

Anyone know for sure? I just want to know so I can sleep tonight.

THANKS!!!

Griff
twoeleven
 

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Geez...now you have me sleepless.
 

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good question....dont know...but

I would not think it is a heat dissipation issue...
- the part itself is not really in a high airflow area...and the difference would be minute IMHO....
- Also, if they were concerned with cooling the master, then you would think it would have some sort of fins or increased surface area to accomplish this.

maybe it is a simplicity issue...brake masters are black cast and clutch cylinders are billet....easy to grab the one you need.
 

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hahah - got you looking at those larry?!

you can get the billet brake MC from yoyodyne (here)

but $2500 for a brake MC?

pass me the cast one please!

alex
 

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Probably just what they pulled out of the parts bin. I don't know whether brembo makes a cast clutch master or not. There seems to be a lot of people claiming the bottom of the line brembo radial racing master is a forged unit, I believe it is a Die cast piece. There isn't really any benefit to using the billet over a forged unit since they would both have the same stiffness. I've heard people say that cast units are more dimensionably stable than billet pieces but I don't know how much truth there is to that. It seems that a cast and billet piece made of the same alloy should have the same thermal properties, afterall a billet is nothing more than a cast piece which starts out as a rectangle or some other geometry before it is machined. A casting just starts out with geometry closer to the finished product.

So the short answer, they probably pulled them from the parts bin and maybe they only make a billet clutch.
 

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With CNC I suppose that they could make slight alterations to the machining process without having to set up new dies etc. Initial design could be machined and then when finally sorted, dies made for mass production. If numbers are limited then billet would be the cheapest and fastest to obtain a finished useable product... It could mean that clutch experimentation is still underway?

Gary
 

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Get a load of that shit, how bizzare.
 

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RobP said:
There isn't really any benefit to using the billet over a forged unit since they would both have the same stiffness. I've heard people say that cast units are more dimensionably stable than billet pieces but I don't know how much truth there is to that. It seems that a cast and billet piece made of the same alloy should have the same thermal properties, afterall a billet is nothing more than a cast piece which starts out as a rectangle or some other geometry before it is machined. A casting just starts out with geometry closer to the finished product.

So the short answer, they probably pulled them from the parts bin and maybe they only make a billet clutch.
I agree, in this type of application....but i think the billet piece is a forged item.

I heard this from a piece on TV on a wheel manuafacturer..one of the Speed shows....they used the following as a comparison....cast is like partical board, and forged is like solid oak. cast items are just poured molten into a mold and cooled...billets and forgings are extruded or pressed unter extreme pressure, which helps align the metal molecules, making a stronger product....but it them must be machined for final finish.
 

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"cast is like partical board, and forged is like solid oak. cast items are just poured molten into a mold and cooled...billets and forgings are extruded or pressed unter extreme pressure, which helps align the metal molecules, making a stronger product....but it them must be machined for final finish."

yes the billet is much stronger than cast.that is odd that they are diffrent!
 

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910rwantobe said:
"cast is like partical board, and forged is like solid oak. cast items are just poured molten into a mold and cooled...billets and forgings are extruded or pressed unter extreme pressure, which helps align the metal molecules, making a stronger product....but it them must be machined for final finish."

yes the billet is much stronger than cast.that is odd that they are diffrent!
Only if the billet is milled from a forged part, and not merely a cast part.
 

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fazer6 said:
Only if the billet is milled from a forged part, and not merely a cast part.
If its milled from cast, its not billet. :stickpoke
 

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Some Guy said:
If its milled from cast, its not billet. :stickpoke
True, I was generalizing i guess. Many times a part is touted as being CNC machined, and people often assume it's the same as a "billet" part. Billet, as previously noted, being an extrusion, and stronger than cast.
 

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Discussion Starter #15
Not that this isn't an interesting debate, it certainly is, and thanks to all for the great insight...BY WHY ARE THEY DIFFERENT??? ON THE SAME BIKE???

I understand "Parts bin mentality" on a production Japanese bike, but we are talking about some of the most exotic and expensive racing machines in the world. Rossi's M1 is a state of the art, carbon fiber fighter jet without wings. The same could be said of the Bayliss machine..

There MUST be a reason that this is done...Where in the world is JamesC on this issue???

I must keep digging, didn't sleep a wink last night, all bothered about this quandry! :ahhh:

Griff
twoeleven :confused:
 

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Ok, looking at Yoyodyne's website I only see a billet clutch master, so the reason might just be there is no cast option for the clutch side. Aside from the material differences, they are essentially the same the important things are the bore diameter (and how it is matched to the slave cylinder or caliper) and the levarage ratio between the pivot and the piston.
 

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twoeleven said:
Where in the world is JamesC on this issue???
I'm hoping to learn as well - I'm no materials engineer! I have to admit though that I thought the Motocorse bikes were billet on both sides, at least the photos I'd seen when in association with their billet reservoirs that directly bolt on.
I'd also assumed they were billet on both sides of the race bikes. Do you have closeups of the m1 and 999 showing them cast?

I'd be very surprised if they weren't touted as 'forged' if they were in fact so.
 

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Discussion Starter #18 (Edited)
JamesC said:
Do you have closeups of the m1 and 999 showing them cast?
Heh...Funny thing is, although I noticed this at the Long Beach show, and it got me thinking, I didn't think enough to take pictures...The whole thing would have probably gone away in my mind, but then Pier posted his link to the interactive Moto Corse Platino, and I saw it there clear as day (those are the pics in the beginnig of the thread).

Anyway, just from the pics I took that day, I can see the 999's clutch master, which looks like a machined piece, and the M1s brake master, which, if you look closely, bears the witness seams of a casting. I remember noticing this first on Rossi's bike, then on Bayliss'...These are the best pics I have.

Griff
twoeleven
 

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Years ago I asked a friend of mine who is a Brembo importer here in the states. This same question was asked directly to Brembo in Italy. The answer is simple. They (Brembo) sell a lot more of the radial Front Brake masters than the Radial Clutch masters. The reason the Brake side is forged, and the clutch side is CNC machined is simply an economical one. Brembo doesnt sell enough of the clutch units to warrant having to tool a forge mold/press for the limited number of clutch units sold.

To bad, because I think having a set of CNC machined radials for both side would look nicer than the "unmatched" pair.

:)

Happy Holidays
 

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Hahaha. Here we are debating the materials and construction methods, and the answer is much more mundane! Too funny, but that's how it works when you have to make a few, or a few thousand.

Alex

daotoys1 said:
Years ago I asked a friend of mine who is a Brembo importer here in the states. This same question was asked directly to Brembo in Italy. The answer is simple. They (Brembo) sell a lot more of the radial Front Brake masters than the Radial Clutch masters. The reason the Brake side is forged, and the clutch side is CNC machined is simply an economical one. Brembo doesnt sell enough of the clutch units to warrant having to tool a forge mold/press for the limited number of clutch units sold.

To bad, because I think having a set of CNC machined radials for both side would look nicer than the "unmatched" pair.

:)

Happy Holidays
 
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