Author Topic: ss brake lines cb550 straight into caliper  (Read 16189 times)

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Offline xsmooth69x

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ss brake lines cb550 straight into caliper
« on: June 10, 2011, 05:04:43 PM »
so i want to get new SS brake lines for my bike.

should i use that metal thing into the caliper or just connect the SS line straight into it?

what is the point of the metal tube?
1975 CB550 (FINISHED?!?!?)
first motorcycle ever!!! ow and i dont know how to ride it either :D

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Offline TwoTired

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Re: ss brake lines cb550 straight into caliper
« Reply #1 on: June 10, 2011, 06:06:40 PM »
The caliper needs to self center around the rotor to minimize drag.  The adjuster spring and the caliper seal supply the force for this, which isn't much.

The hard line pivots with the caliper so it can center, without brake line bias tension.

If you don't care about brake drag, or hydraulic line tension imposing side loads on the caliper, it will stop fine without the hard line.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline xsmooth69x

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Re: ss brake lines cb550 straight into caliper
« Reply #2 on: June 10, 2011, 06:28:36 PM »
so it is important?
1975 CB550 (FINISHED?!?!?)
first motorcycle ever!!! ow and i dont know how to ride it either :D

raw rust rice venti quad shot cafe racing latte project aka my build..... http://forums.sohc4.net/index.php?topic=88853.0

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Offline scottly

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Re: ss brake lines cb550 straight into caliper
« Reply #3 on: June 10, 2011, 07:59:00 PM »

The hard line pivots with the caliper so it can center, without brake line bias tension.

Cheers,

How is the hard line free to pivot when the rear is attached to the fork-leg via the rubber bushing and fender brace?
In what world is hard line more flexible than braided SS?  :o :o :o
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Offline xsmooth69x

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Re: ss brake lines cb550 straight into caliper
« Reply #4 on: June 10, 2011, 08:43:51 PM »
^ kind of thought the same thing but then i thought when you squeezed on the brakes it makes the cable move and the metal part that is attached to the fender dosnt let the squeezed line move?
1975 CB550 (FINISHED?!?!?)
first motorcycle ever!!! ow and i dont know how to ride it either :D

raw rust rice venti quad shot cafe racing latte project aka my build..... http://forums.sohc4.net/index.php?topic=88853.0

black and white equation godzilla chalkboard 
1972 cb750 - next in line for some <3

Offline Hannibal Smith

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Re: ss brake lines cb550 straight into caliper
« Reply #5 on: June 10, 2011, 08:52:33 PM »
Would have to think about it more in depth, but hard-line makes things more predictable in certain situations.
If the hard line starts below deflection (front fork movement) then an engineer would know that the assembly would stay constant, and eliminate the possibility of line running into the spokes etc.
This is of course a quick thought (4 beers doesn't help) but Honda were some smart cookies back in the day, so think about things long and hard when it comes to the glorious SOHC!
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Offline scottly

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Re: ss brake lines cb550 straight into caliper
« Reply #6 on: June 10, 2011, 09:12:02 PM »
Would have to think about it more in depth, but hard-line makes things more predictable in certain situations.

How? Justify your work, as they used to say in math class. ;)
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Offline xsmooth69x

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Re: ss brake lines cb550 straight into caliper
« Reply #7 on: June 10, 2011, 09:43:50 PM »
so use the old metal thing or not.... as long as the SS brake line doesn't have slack on it ?
1975 CB550 (FINISHED?!?!?)
first motorcycle ever!!! ow and i dont know how to ride it either :D

raw rust rice venti quad shot cafe racing latte project aka my build..... http://forums.sohc4.net/index.php?topic=88853.0

black and white equation godzilla chalkboard 
1972 cb750 - next in line for some <3

Offline scottly

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Re: ss brake lines cb550 straight into caliper
« Reply #8 on: June 10, 2011, 09:50:05 PM »
No, you don't "need" the hard line.
You NEED slack in the hydraulic SS line to allow for suspension travel.
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Offline TwoTired

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Re: ss brake lines cb550 straight into caliper
« Reply #9 on: June 10, 2011, 10:29:51 PM »

The hard line pivots with the caliper so it can center, without brake line bias tension.

Cheers,

How is the hard line free to pivot when the rear is attached to the fork-leg via the rubber bushing and fender brace?
In what world is hard line more flexible than braided SS?  :o :o :o

Pretty simple mechanical physics, really.
The capture grommet is a very loose connection which behaves as a pivot or fulcrum, and is well behind the actual caliper arm pivot.  None of the arm deflective moments are very great at that point, so the arm and hard line both pivot freely, so as not to interfere with caliper centering.

It is the real world where a flexible line attached to the caliper body applies more side force to the caliper than the hard line properly routed.  It's pretty clear that Honda engineers had more training and knowledge about this, than home brew modifiers.

You can demonstrate this to yourself.  Hold a yardstick in your hand, and place a 1 pound object on the end of it.  The force applied to your hand is three foot pounds.  Put the one pound weight at the one foot mark away from your hand.  Now you are only lifting 1 foot pound and you will find it much easier to hold the weight up.  With the weight or force farther away, it takes more force to effect movement or deflection farther away, given the same force applied.  If you have ever operated a simple lever, you have already experienced these physics.

The fulcrum when a biased or under tension brake line is attached directly to the caliper, is applied at the caliper fitting.  SS brake lines, while flexible, do have a reflexive memory.  Go ahead, bend one.  It won't stay exactly at the new position you put it in, unless you fasten it there.  In fact, its reflexive memory is far greater than the caliper seal retraction effort, and possibly the adjuster spring, depending on how the line is routed.

Just like the weight at the end of the arm was magnified at your hand (fulcrum) by moving the force farther away from the fulcrum, the hard line attachment distance from the caliper makes it easier to pivot at the grommet location. The Calipers retraction or movement force is magnified by the distance or lever arm of the hard line at the grommet/stay.

The analysis only applies to lateral movement of the caliper.  The vertical and longitudinal axis is constrained pretty tightly by the caliper pivot arm.

It occurs to me that some may not understand the proper hard line installation procedure.  With the hard line properly routed, the hard line length touches nothing but the end points, and the fitting at the fender stay would float within that stay centered in the wire loop without the grommet installed.  All the grommet does is eliminate chafing under G loads while driving.  If the line is not deform from the shape given by the factory, it will all stay in alignment when reinstalled.  However, if an untrained mechanic bends the hard line out of ignorance, then of course the system can't work as designed.

As XS correctly pointed out, when the lines come under pressure they move as the forces distribute along the length of the line.  The fender stay helps to keep that movement from affecting the caliper.  However, during caliper actuation, these forces are really insignificant.  It is the caliper release and drag prevention that the original design dealt with effectively.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline xsmooth69x

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Re: ss brake lines cb550 straight into caliper
« Reply #10 on: June 11, 2011, 02:10:58 AM »
dude your explanation are amazing!!!

ok so im going to use that metal line...... about the careless mechanic... ya thats me.... i might have kinda probably bent them.... is there anyone that makes those  ;D
1975 CB550 (FINISHED?!?!?)
first motorcycle ever!!! ow and i dont know how to ride it either :D

raw rust rice venti quad shot cafe racing latte project aka my build..... http://forums.sohc4.net/index.php?topic=88853.0

black and white equation godzilla chalkboard 
1972 cb750 - next in line for some <3

bollingball

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Re: ss brake lines cb550 straight into caliper
« Reply #11 on: June 11, 2011, 06:32:23 AM »
Don't know about the 550 but Honda still has them for the K8 750. Have you looked?

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Offline TwoTired

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Re: ss brake lines cb550 straight into caliper
« Reply #12 on: June 11, 2011, 07:36:47 AM »
dude your explanation are amazing!!!

ok so im going to use that metal line...... about the careless mechanic... ya thats me.... i might have kinda probably bent them.... is there anyone that makes those  ;D

It is not that hard to reform a bent hard line.  Just dry assemble the caliper and fender components onto the fork without the fender stay grommet.  Then "massage" the hard line so it touches nothing between caliper fitting and still centers itself on the grommet stay without the flex hose attached.

Have I correctly noted a reluctance to reassemble bits knowing it won't be the final assembly on your part? 
I remember in my early days of mechanical learning, I would put assemblies, like carbs, together and find parts left over that I knew went inside them somewhere.  The assembly process became reiterative, until I figured out where all the parts went and had none left over when assembly was completed.  It would take 3-5 tries, sometimes, to get it all right.  (My first 4 barrel carb took six tries!  And, my first lawn mower engine took 10-20.  But, that was because it was my dad who took it apart and all I got was a box o' parts with absolutely no disassembly sequence or documentation.) Anyway, along with learning the particular machine components, I also learned a methodology for disassembly to help get all the components back in.  For example: you can marker number the  "wells" in an egg carton or similar compartmental container.  As you remove groups of screws/bolts, etc. you put them in sequential compartments.  This way, you know which parts/screws go in next upon reassembly, without relying on memory.  You also don't install bits out of sequence so you minimize repeated disassembly to get all the bits back in.  You know that all the parts of bins 8-6 must go in before ANY parts in bin 2 go in.  If you don't have sequential bins now, you can use the "dry fit" mock up process to make one.

Anyway, as you learn, don't be afraid of experimentally putting the thing or sections of it back together knowing full well you will just take it apart again.  I suppose all this is just another way of saying "practice makes perfect".  In this way, experience is gained.  ;D

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline xsmooth69x

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Re: ss brake lines cb550 straight into caliper
« Reply #13 on: June 11, 2011, 08:45:09 AM »
wow the egg carton idea is great!!!

i actually went to the dollar store and picked up a bunch of muffin trays  ;D

and i use my sony bloggie digi cam to take lots of pics!! i use my nice cannon to take forum pics but ya thank god for digi cams

ya im not sure if its super bent or anything but i deff wasn't being careful moving it around

1975 CB550 (FINISHED?!?!?)
first motorcycle ever!!! ow and i dont know how to ride it either :D

raw rust rice venti quad shot cafe racing latte project aka my build..... http://forums.sohc4.net/index.php?topic=88853.0

black and white equation godzilla chalkboard 
1972 cb750 - next in line for some <3

Offline myoldcb200

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Re: ss brake lines cb550 straight into caliper
« Reply #14 on: June 11, 2011, 11:43:46 AM »
Guess its another dumb question, (mainly dumb because after Ive asked a few questions Ive actually found the answer someplace on the site) but I noticed in the picture that at the top of the hardline there is what looks like a piece that fits in the grommet stay. Bending your own lines and putting it in without that piece can cause drag? Is there an extra piece that fits to the hardline that fits in the grommet that i am not seeing in my books? I assumed it was ok to just bend the hard line and let it sit in that grommet.?
 And while i am at it lets just make it totally stupid and ask what ss brake lines are and whats the difference between them and the stock ones. Or maybe link to a read about them? Currently rebuilding front brakes on the 74 750 and just want it to be ok with any solid upgrades made to it while i am at it.
The bike I am working on is --->1974 cb750 k4

Offline xsmooth69x

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Re: ss brake lines cb550 straight into caliper
« Reply #15 on: June 11, 2011, 04:27:11 PM »
i can address some things. i am building a honda cb550 for the first time and i am completely a newb but this is what i know

SS lines brake lines are "stainless steel" brake lines

stock lines are rubber and over time they get weak. what that means is that when you squeeze the brake lever the actual brake line rubber hose expands and could make your lever feel squishy of not act sharp enough.

with stainless steel brake lines it will feel nice and stiff and the brakes will act sharp since the stainless steel brake lines wont flex as much under braking.

SS lines also look cool and you can say they are "safer" to justify there price. safer as in you SS line is less likely to blow out compared to the rubber  ;)

as for the second part of the question

in the first picture the green circle is the grommet that moves freely up and down the until u press it into your fender. this rubber piece holds the line into the fender

in the second picture you can see the fitting that the third picture fits in. they just screw into each other

also in the 3rd picture u can notice on the old metal like the person who took the picture didnt unscrew the line from the brake line. so you can see with the fitting how they fit.

i hope this helps

also this thread has a link to cheap and amazing brake lines. this is where im going to get mine

http://forums.sohc4.net/index.php?topic=88457.msg993798#msg993798

u should contact the seller on ebay too btw dont try to make your lines through his listings. u can custom make your lines to fit your application. i just ordered clip on handle bars so the top SS line will be shortened.

also u can just replace just 1 ss line going from the caliper to the tri block. <----- im not sure if thats the right terminology for the brake like slitter that goes to you master cylinder and also activates your brake lights.

or you can go all out and replace both. with the ebay seller it is cheap to do both so do both!
« Last Edit: June 11, 2011, 04:35:25 PM by xsmooth69x »
1975 CB550 (FINISHED?!?!?)
first motorcycle ever!!! ow and i dont know how to ride it either :D

raw rust rice venti quad shot cafe racing latte project aka my build..... http://forums.sohc4.net/index.php?topic=88853.0

black and white equation godzilla chalkboard 
1972 cb750 - next in line for some <3

Offline scottly

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Re: ss brake lines cb550 straight into caliper
« Reply #16 on: June 11, 2011, 09:56:30 PM »




It is the real world where a flexible line attached to the caliper body applies more side force to the caliper than the hard line properly routed.  It's pretty clear that Honda engineers had more training and knowledge about this, than home brew modifiers.

[/quote]
In my real world experience, my home brew flexible braided SS lines put negligible side loads on the calipers. In fact, the calipers without the adjuster springs will swing freely just by turning the forks from lock-to-lock. The adjuster spring applies much more force (>2 pounds at the caliper) than the line; not an issue.
Also, the primary purpose of the grommet is to support the end of the rigid line; without this support, the line will crack from fatigue from constant flexing.   
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Offline TwoTired

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Re: ss brake lines cb550 straight into caliper
« Reply #17 on: June 11, 2011, 10:59:02 PM »
Also, the primary purpose of the grommet is to support the end of the rigid line; without this support, the line will crack from fatigue from constant flexing.   
I disagree.
The grommet transfers loads of the flexible line from above that join point into the fender stay so the hard line does no "flexing" whatsoever.  The hard line simply pivots along with and in unison to the caliper mount arm.  If you found one of those hard lines on the SOHC4 that cracked, it wasn't inherent to the design, but rather from some ham hand "repairing" it incorrectly, and misunderstanding how the assembled parts function as a system.  These systems have hundreds of thousands of miles and use, and STILL function as designed without failure.

I hope your modification proves to perform as well.  But, I won't be trying it unless the original option becomes impossible due to part unavailability.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline scottly

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Re: ss brake lines cb550 straight into caliper
« Reply #18 on: June 11, 2011, 11:12:39 PM »
Also, the primary purpose of the grommet is to support the end of the rigid line; without this support, the line will crack from fatigue from constant flexing.   
I disagree.
The grommet transfers loads of the flexible line from above that join point into the fender stay so the hard line does no "flexing" whatsoever
Read what I wrote again... ;)
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Offline socalenduro

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Re: ss brake lines cb550 straight into caliper
« Reply #19 on: June 13, 2011, 11:06:04 PM »
ok to further muddy the waters....
for those of us not running a fender the hard line is not doing a thing correct?
being as the grommet at the top cannot hold the line in place...

Offline scottly

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Re: ss brake lines cb550 straight into caliper
« Reply #20 on: June 13, 2011, 11:15:00 PM »
Without the grommet and it's support from the fender brace, the hard line will eventually fail. 
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Offline betterthanurs916

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Re: ss brake lines cb550 straight into caliper
« Reply #21 on: June 13, 2011, 11:29:04 PM »
Just convert to mechanical disk brakes like the CB200T and you won't have to worry about it ;) lol...

But seriously.  Along with what all was said above, I suspect another reason Honda chose hard line for this portion of the brake line is the simple fact that it is pretty much common practice to use hard line wherever possible.  Hard line has a negligible amount of flex under pressure, and for that reason does not allow for as much hysterisis in the system as compared to a system with all soft line.

If you're set on replacing everything with braided line, you're probably going to be a little better than the stock configuration, but I would keep the hard line...it would be the easiest option and your best bet for braking performance.

This site is down right now, and may be the same vendor as your ebay seller...but I believe this guy is also on the forum and his stuff looks pretty nice. I would give it a look.

http://slingshot-cycles.com/index.php?main_page=down_for_maintenance
1977 CB550F2

Offline scottly

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Re: ss brake lines cb550 straight into caliper
« Reply #22 on: June 14, 2011, 12:14:54 AM »
Along with what all was said above, I suspect another reason Honda chose hard line for this portion of the brake line is the simple fact that it is pretty much common practice to use hard line wherever possible.  Hard line has a negligible amount of flex under pressure, and for that reason does not allow for as much hysterisis in the system as compared to a system with all soft line.
7 inches of hard line vs 2 feet of soft? Back in the day, braided SS lines were only used in aviation; it would have been prohibitively expensive to be used on mass production motorcycles. Those of us that openly embrace advances in technology are free to improve the performance of our vintage machines, while those that believe that a 40 year old design can't be improved on are locked in the past. I can appreciate a pure stock bike, and admire the determination required to maintain one in full working order and appearance, but even Honda determined the original braking system could not compete with the other manufacturer's offerings as early as the late '70's. While the dual disc Kawi's were available off the show-room floor, the dyed-in-the-wool Honda guys were forced to do conversions using stock parts.   
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Offline neverendingproject

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Re: ss brake lines cb550 straight into caliper
« Reply #23 on: June 14, 2011, 01:50:44 AM »
SS lines also look cool and you can say they are "safer" to justify there price. safer as in you SS line is less likely to blow out compared to the rubber  ;)


I would say safety depends a lot on what manufacturer you get the braided line from. Having said that, I have no suggestion on where to get one  ;) Also you can't see what's happening under the stainless braid but if everything is right they should be very reliable.

Oh and don't over think this just use common sense and make sure the new line is protected from chafing, heat etc. and also be sure it has enough slack for turning with(out) the suspension compressed.
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Offline dave500

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Re: ss brake lines cb550 straight into caliper
« Reply #24 on: June 14, 2011, 02:09:36 AM »
the stainless brake lines arent pure stainless,they have rubber under the stainless cover.