Author Topic: simple brake improvements  (Read 2035 times)

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Offline 1974blaze

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simple brake improvements
« on: May 08, 2009, 07:37:44 AM »
i'm curious, and not knowing much i hope this isn't a stupid question. 

can you use a larger master cylinder connected to a stock cb750 set up and get the thing to stop faster?

if possible, would id damage the caliper/rotor?

thanks all

Offline TwoTired

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Re: simple brake improvements
« Reply #1 on: May 08, 2009, 07:46:40 AM »
Have you switched to SS brake lines yet?
Lloyd... (SOHC4 #11 Original Mail List)
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Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline 1974blaze

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Re: simple brake improvements
« Reply #2 on: May 12, 2009, 10:33:14 PM »
you mean stainless? no, what would that do? better volume.?

taymoor

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Re: simple brake improvements
« Reply #3 on: May 13, 2009, 12:00:06 AM »
Ya... How does that help? I thought it just looked good.

Offline ev0lve

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Re: simple brake improvements
« Reply #4 on: May 13, 2009, 12:17:13 AM »
Doesn't expand under pressure. But they do look good too  ;D

Offline martino1972

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Re: simple brake improvements
« Reply #5 on: May 13, 2009, 12:25:29 AM »
poor guy just came new to the forum and already you guy's are giving short answers........TT,I'm used to reading 1000+ letter responses from you.... ;D ;D ;D ;D ;D

welcome to the forum,1974blaze.......it's a blaze...um blast here on the forum....wicked humor,great advise,awesome bunch of people..... ;)
Marti, I want you to know, I like you an awful lot, but guys have said far less and left wearing their drinks on their shirts.
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Offline FunJimmy

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Re: simple brake improvements
« Reply #6 on: May 13, 2009, 12:37:43 AM »
There are many things that can be performed to improve the braking of mid ‘70’s motorcycles. As you have seen posted, changing to a stainless steel braided brake line can improve braking efficiency by increasing the pressure rating of the hydraulic brake line. A higher pressure rating will reduce fluid pressure losses at the caliper.

Another approach is to modify the leverage ratio by adjusting the master cylinder piston size compared to the caliper piston size. A hydraulic system is essentially a fluid based lever. The difference between the master cylinder piston and the caliper piston it essentially the lever ratio.

Here are a couple of articles that are worth a look: http://science.howstuffworks.com/pulley1.htm and http://science.howstuffworks.com/hydraulic1.htm

You should be able to measure the existing master cylinder piston and adjust to improve feel, modulation and overall power.

Good luck
FJ
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Offline TwoTired

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Re: simple brake improvements
« Reply #7 on: May 13, 2009, 12:45:11 AM »
you mean stainless? no, what would that do? better volume.?
No.  The original hoses are rubber with woven fabric embedded in them to reduce expansion.  The constant pressure cycles eventually fatigue the materials and reduce their rigidity.  The result is that some of the pressure applied goes to expanding the hose rather the moving the pad against the rotor to increase friction.

Replacing with stainless steel braided hose, makes nearly all the pressure developed in the master cylinder to be transferred entirely to the caliper piston, resulting in better brakes.

Replacing 30 year old fatigued rubber hoses with SS makes a large difference in braking power.  I could squall the front tire on my 550's in a panic stop on asphalt.  I believe that is better that locking the front tire.  Still have to use four fingers on the lever, though.  If you insist on having one finger brakes, you'll have to swap out the whole system with modern components with multi-piston calipers.

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 Buber

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Re: simple brake improvements
« Reply #8 on: May 13, 2009, 12:49:37 AM »
Replacing 30 year old fatigued rubber hoses with SS makes a large difference in braking power.
That's an undertstement. It makes HUGE difference, and it's well worth it. With SS lines I can ride with two fingers on the lever, and be able to pull a quick stop.
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Offline lordmoonpie

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Re: simple brake improvements
« Reply #9 on: May 13, 2009, 04:22:59 AM »
+1 to that - if you take TT's comments to the extreme, some rubber hoses can fatigue in spots and when you pull the lever you actually blow a bubble out of the side of the brake line. It's quite funny to watch but only when you're not riding!

SS brake lines will be the cheapest most effective single upgrade you can do to old brakes....
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Offline 1974blaze

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Re: simple brake improvements
« Reply #10 on: May 13, 2009, 12:10:17 PM »
well!  ok gents, now that's some good stuff.  it seems i've come to the right place.  thanks to all, i will be making the switch asap and will let you know how she turns out.  will also read the article on cylinder ratios and see where that leads. 

ev0lution7

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Re: simple brake improvements
« Reply #11 on: May 13, 2009, 02:12:01 PM »