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General Discussion
Started by kingston73 at 05-07-2008 10:11 AM. Topic has 9 replies.
  
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 05-07-2008, 10:11 AM
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kingston73
 
Joined on 04-19-2008
Norton, MA
Posts 306
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Brakes, Calipers, Master Cylinders, you get the idea....
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I know the "brakes" subject has been brought up on a million posts, I've read dozens but haven't found this answer, or at least haven't found a non-contradictory answer.
What would a more effective upgrade be, rebuild my single piston caliper and get a M/C lever assembly from a more modern bike with a larger fluid displacement, or keep my current M/C lever and get a dual piston caliper?
I just rebuilt my master cylinder, but I think my caliper is probably frozen, or at least needs a good cleaning, based on how bad the brake fluid was. I don't want to spend the time and money rebuilding my single piston caliper if a dual caliper would be more effective, but from reading the posts it seems like a dual piston caliper is hit or miss as to whether it's a simple bolt on or if it needs a bracket.
1979 cx500D/1980 CX500C engine
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05-07-2008, 2:58 PM
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mildhog
Joined on 11-21-2007
Chesapeake, VA
Posts 433
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Re: Brakes, Calipers, Master Cylinders, you get the idea....
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I might be wrong but I don't think fluid displacement on a single would make a difference. However, a dual piston or dual caliper setup would need more fluid therefore, a bigger MC. You'd get more stopping power from a dual piston and even more from a dual caliper.
Arnie in VA
1982 GL500I Silverwing
1983 GL650
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05-07-2008, 3:37 PM
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kingston73
Joined on 04-19-2008
Norton, MA
Posts 306
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Re: Brakes, Calipers, Master Cylinders, you get the idea....
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I guess my terms weren't quite right. I don't want to change my fork to a dual caliper setup, just thinking of changing my single piston to a dual piston setup. I have read some of the posts saying a change in the master cylinder will make the single piston feel stronger, while other posts say keep the single piston M/C and change the caliper to a dual piston. I just dissassembled my caliper, and it was rusted inside, with a lot of solidified brake fluid in the piston ring groove. I've cleaned it and used steel wool on the rust, and if looks and feels smooth inside and out now, but I don't know if I entirely trust it anymore.
1979 cx500D/1980 CX500C engine
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05-08-2008, 5:15 AM
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RodW
Joined on 02-18-2008
Posts 15
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Re: Brakes, Calipers, Master Cylinders, you get the idea....
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In the case of master cylinders bigger is not necessarily better. If you increase the area of the piston in the m/c there will be less movement of the lever for a given applied force when you squeeze the brake. It will therefore probably feel "stronger" but in reality less force is being applied to the brake pads and the stopping distance will increase. See this site, it may explain hydraulics better. It is the second diagram down the page that is relevant.
http://www.grc.nasa.gov/WWW/K-12/WindTunnel/Activities/Pascals_principle.html
So to increase braking power for the same force applied at the lever either reduce m/c piston size or increase caliper piston size or have 2 caliper pistons. This in theory should mean the lever moves further but when I changed from twin single piston calipers to twin double piston calipers I actually found that if anything the lever moved very slightly less, which doesn't sound right but I did change to braided hose at the same time. Another thought was perhaps the pistons in the double piston calipers don't retract as far as the single piston when you release the brake so don't have as far to travel to contact the disk when you apply the brake but that is just my theory.
I actually changed disks and calipers to those off a CB900. Not only do you get more caliper piston area but bigger disks too, up from 240mm to 280mm which is also good. I suspect the single disk machines already have the bigger disk so no room for improvement there.
I'd also recommend using dog leg levers, think they are also called power levers.
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05-10-2008, 2:23 PM
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kingston73
Joined on 04-19-2008
Norton, MA
Posts 306
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Re: Brakes, Calipers, Master Cylinders, you get the idea....
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Well, now I have another brake related question. Before I started reading all the "dual piston" posts, I ordered a rebuild kit and put new rubber into it, as well as new pads. Now I'm wondering if my newly put together single piston, with a steel line, will be good enough, or if I should spend more money, buy a dual piston and all the new material that goes with it...
How bad is the single piston, really? I haven't ridden a motorcycle for years, and I've never ridden anything that could be considered a "performance" bike, so I don't have anything to compare my cx's stopping power to other than my pickup. Are the people who say the cx just sort of "slows down" exagerating, or using 20 year old parts that don't work as well as a rebuilt system?
1979 cx500D/1980 CX500C engine
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05-13-2008, 12:00 PM
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Randall-in-Mpls
Joined on 07-06-2007
Minneapolis, MN
Posts 1,110
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Re: Brakes, Calipers, Master Cylinders, you get the idea....
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I think the single pot caliper in my CX is just fine, and I'm not a small guy. I am a somewhat conservative rider, though. I can see how it might underperform for a more aggressive riding style.
R
'78 CX500 - The Black Maggot
My mid-life crisis has two wheels.
CX500 Factory Service Manual
(Downloadable by chapter)
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05-22-2008, 12:12 AM
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Daniel45mpg
Joined on 05-18-2008
Murrieta, CA.
Posts 173
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Re: Brakes, Calipers, Master Cylinders, you get the idea....
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I went through my front brake system last summer.
first rebuilt Master-cylinder because it was leaking (everything).
5 percent better braking power.
then rebuit Caliper (because of leak and sticking)
10% pecent better
Broke down for steel brake line.
WOW 50% better way harder less spongy more of a clamp feel.
new pads made a big differance also 20% better
1980 CX500C
1980 CX500D
Renew, Reuse, Recycle.
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05-22-2008, 12:21 AM
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Daniel45mpg
Joined on 05-18-2008
Murrieta, CA.
Posts 173
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Re: Brakes, Calipers, Master Cylinders, you get the idea....
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i forgot to mention i use my brake hard and stop fast some times for practice. That extra grab on the single caliper pulls the cx to the right on super hard practice stops which is not a fun feeling. The bike is what it is. it has it limits. I find comfort in finding what those are.
1980 CX500C
1980 CX500D
Renew, Reuse, Recycle.
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05-22-2008, 7:22 AM
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Exothermia
Joined on 04-18-2008
Posts 116
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Re: Brakes, Calipers, Master Cylinders, you get the idea....
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I'm going to have to do the same thing this summer. My front brake stops and doesn't leak but it is spongy and wouldn't lock up to save its life. From everything I hear, people who have rebuilt their calipers with new pads and stainless lines got pretty decent braking, and that's really all I need. I don't think a total brake conversion is necessary because these brakes really aren't that bad if they're functioning at the level they were designed to when new.
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05-22-2008, 8:43 AM
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kingston73
Joined on 04-19-2008
Norton, MA
Posts 306
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Re: Brakes, Calipers, Master Cylinders, you get the idea....
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Well, granted I haven't much experience with my "new" cx, and it's been 10 years since my cb650, but I did the full rebuild and new pads and stainless line, and the few times I've ridden it I've been really happy with it. It took a little bit of time to bleed, but I left the lever tied up over night and now it feels very firm. The lever travels about 1/2 it's distance and the bike stops fairly well. Granted, I haven't gotten up to high speeds yet and haven't done any panic stop practice....yet. I need to sort out some speedometer and coolant issues first.
1979 cx500D/1980 CX500C engine
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