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05-02-2008, 10:51 AM Jonathan_P Joined on 03-22-2008 Austin, Texas Posts 26 brakes?! I almost died! Yeap....my front master cylinder is shot and had a close call. I cant seem to find one online. Any one know of an online place i might be able to find one or.......some kind of aftermarket set up that would work on a '79 CX500 Custom? Thanks!    Report

05-02-2008, 11:28 AM Anonymous Re: brakes?! I almost died! http://www.siriusconinc.com/default.asp I've been quite happy with their parts.  Good luck.

05-02-2008, 1:21 PM snooksion Joined on 12-21-2007 cape coral Posts 38 Re: brakes?! I almost died! glad you didnt get hurt ThE bOrN lOsEr    Report

05-04-2008, 12:02 PM makenzie71 Joined on 03-30-2007 TX Posts 303 Re: brakes?! I almost died! Any master will work.  the ones I sell in my brake kits are similar to what you find on SV1000's. Available from EssGlass ATV/Motorcycle Fabrication ~Preload adjusters (CX5/applicable): $55 + core caps ~310mm big brake kits (CX5/applicable): starting at $125 ~Left exit divorced exhaust: $225 for info email me!    Report

05-19-2008, 7:01 AM Sidecar Bob Joined on 03-02-2006 Kawartha Lakes, Ontario Posts 926 Re: brakes?! I almost died!  Jonathan_P wrote: Yeap....my front master cylinder is shot What exactly do you mean by this? Unless your master cylinder is physically damaged (cracked or broken) or it's bore has worn out of round (not common) or has become scored (I've never seen one) the problem is usually easier to fix than you would expect. There are 2 main master cylinder problems that occur on machines this old: 1) The brakes lock up without any lever application. This is caused by a blocked return port in the bottom of the master cylinder and can usually be fixed by clearing out the hole with a sewing needle. 2) You squeeze the lever and the brakes do not apply. There are several causes for this, including air in the brake line, worn out rubber parts and worn out levers. If you have never put a kit into your master cylinder you probably should. 29 years in brake fluid is a long time, even for rubbers that were designed for it. Even if your master cylinder seems to be working properly, it wouldn't hurt to replace rubber parts that old. Most people don't realize that brake levers are wear items. The bump that presses on the piston can eventually wear away so that it can no longer push the piston far enough to fully apply the brake. This is usually indicated by excessive play when the lever is released. A poorly coppied aftermarket lever or the wrong lever for the master cylinder can cause the same problem. It can sometimes be remedied by drilling & tapping a hole in the lever's bump and putting a small round headed screw in. If you do end up actually needing a replacement, there are 3 considerations: 1) Bore diameter. Master cylinders for models with dual discs must displace twice the fluid for a given lever stroke than ones for single disc models. If you use a dual disc MC with only one caliper the lever will have less travel than it should and modulation of the brake will be more difficult. If you use a single disc MC with 2 calipers it will need twice the lever movement to apply the brake and in some cases the lever may reach the handlegrip before the brake is fully applied. SIngle disc MCs are usually 1/2" bore and dual disc MCs are 5/8" 2) Handlebar diameter. 3) The angle the mreservoir sits at. Some models (including customs) have master cylinders with the reservoirs at an odd angle so that they sit level when mounted on the oddly bent handlebars. GX650EI + Velorex 700 (winter), '83 GL1000 (summer) '84 CB750SC Nighthawk (died - anyone need parts?)    Report

05-19-2008, 7:25 AM Jonathan_P Joined on 03-22-2008 Austin, Texas Posts 26 Re: brakes?! I almost died! Well, I'm not an expert at master cylinders but two different Honda motorcycle shops, one in San Antonio and one in Austin, took a look at it. Three different cycle shops around the area (one that is a highly trusted family friend who has been in business for 20 years actually worked on it with a new kit) told me the exact same thing...I need a new MC. It actually does have a crack in it, the reservoir leaks, and the breaks do not apply at all. I understand i also need to replace the rubber housing as well because its old. Before buying this motorcycle, i was a pro cyclist and bike mechanic and i have learned that some things in the cycling industry transfer over to motorcycles (i know some of you may be rolling your eyes at this but its true). Maintenance is key unless you want to die on two wheels. So i understand that keeping a well oiled machine is important for many reasons including safety. So i dont want to risk it, several shops have told me the exact same thing that was reinforcing my gut instinct so im going to heed their advice by looking for a new MC. Thanks Sidecar for the words of experience. I am planning on changing out my bars to something straighter so i will probably be looking for a new MC that fits the angle on them.    Report

05-19-2008, 8:31 AM makenzie71 Joined on 03-30-2007 TX Posts 303 Re: brakes?! I almost died! Look for TL1000/GSXR masters.  They're almost all 5/8" (except TLS and earlier GSXR600) and have anything after 1997 has a remote reservoir.  That remote reservoir is a necessity, in my opinion, for anyone who's made changes from stock bars. I, personally, wouldn't stop at replacing the master cylinder.  If the hose is still stock, throw it away and get a new one.  I would upgrade the caliper as well. Available from EssGlass ATV/Motorcycle Fabrication ~Preload adjusters (CX5/applicable): $55 + core caps ~310mm big brake kits (CX5/applicable): starting at $125 ~Left exit divorced exhaust: $225 for info email me!    Report

05-19-2008, 8:44 AM Sidecar Bob Joined on 03-02-2006 Kawartha Lakes, Ontario Posts 926 Re: brakes?! I almost died!  Jonathan_P wrote: It actually does have a crack in it, the reservoir leaks, In that case, it sounds like you really do need to replace the whole thing. You would not believe how many people think they need to replace a part that can be easily & cheaply fixed. I understand i also need to replace the rubber housing as well because its old. Rubber housing? Before buying this motorcycle, i was a pro cyclist and bike mechanic and i have learned that some things in the cycling industry transfer over to motorcycles (i know some of you may be rolling your eyes at this but its true). Not me. I started fixing my own bicycles before I was old enough to understand the difference between pliers and a wrench. So did my friend down the road who grew up to be a mechanic at a Honda/Yamaha dealer. When I got my first motorcycle at age 35 I asked him if he could fix something on it for me. He said "Why? You have been fixing your own bicycles forever so you should be able to do your own work on motorcycles." He told me to take my Haynes manual and sit on a box next to the bike while reading over the section and looking at the bike, then call him back to ask questions. A half hour later I called him and said "It's done. You were right. That was easy." I haven't paid anyone to work on a bike in the 20 years since. Maintenance is key unless you want to die on two wheels. Right. That and paying attention to the idiots in cages that sometimes seem to be trying to kill you. GX650EI + Velorex 700 (winter), '83 GL1000 (summer) '84 CB750SC Nighthawk (died - anyone need parts?)    Report

05-19-2008, 8:55 AM Sidecar Bob Joined on 03-02-2006 Kawartha Lakes, Ontario Posts 926 Re: brakes?! I almost died!  makenzie71 wrote: Look for TL1000/GSXR masters.  They're almost all 5/8" We're talking about a '79 custom. It has a single disc so 5/8" bore master cylinders are not applicable. If the hose is still stock, throw it away and get a new one. I agree. Rubber brake lines are only designed to last for 2-3 fluid changes (5-6 years). They deteriorate due to ozone in the air, ultra violet from sunlight, and contact with brake fluid. Have you ever wondered why brake fluid turns red/brown after a couple of years? it's a combination of oxydization caused by the moisture that finds it's way through the porous rubber and rubber particles suspended in the fluid. I think it is obvious that this reduces the incompressability of the fluid, and thus impairs the function of the brake. Not to mention what can happen if the water boils because the caliper gets hot. Stainless steel braided brake lines are NOT made with rubber. They are made by braiding stainless steel wire over a teflon tube. Teflon is NOT porous. It will not allow any contaminants into the fluid. The braided wire covering protects the teflon tube from damage and also increases the stiffness of the already dimensionally stable tube. They use stainless steel because it does not corrode. See www.goodridge.net If you wrap one hand around a rubber line and squeeze the lever with the other you will feel the tubing expand. This is fluid moved by the master cylinder that doesn't contribute to the movement of the caliper piston(s). In other words: lost braking power. If you wrap your hand around a braided ss line and apply the brake you will feel the line stiffen, but it will not expand. With rubber lines you need to change the fluid every couple of years. Rubber lines should be replaced about every 2-3 fluid changes (every 5-6 years). With stainless braided lines you can leave the fluid in at least twice as long as with rubber. Stainless braided lines should last forever unless mechanically damaged and I have no problem leaving the fluid in them for 4-5 years. It would probably be OK to leave it longer. See this link: http://www.tirerack.com/brakes/goodridge/warranty.jsp Stainless lines are usually cheaper than than original rubber ones too. GX650EI + Velorex 700 (winter), '83 GL1000 (summer) '84 CB750SC Nighthawk (died - anyone need parts?)    Report

05-19-2008, 9:02 AM makenzie71 Joined on 03-30-2007 TX Posts 303 Re: brakes?! I almost died!  Sidecar Bob wrote: We're talking about a '79 custom. It has a single disc so 5/8" bore master cylinders are not applicable. It applicated to mine and thousands others just fine. Available from EssGlass ATV/Motorcycle Fabrication ~Preload adjusters (CX5/applicable): $55 + core caps ~310mm big brake kits (CX5/applicable): starting at $125 ~Left exit divorced exhaust: $225 for info email me!    Report

05-19-2008, 12:10 PM Sidecar Bob Joined on 03-02-2006 Kawartha Lakes, Ontario Posts 926 Re: brakes?! I almost died! As I said before "Master cylinders for models with dual discs must displace twice the fluid for a given lever stroke than ones for single disc models. If you use a dual disc MC with only one caliper the lever will have less travel than it should and modulation of the brake will be more difficult." Someone else posted an explanaton recently of why this is a really bad idea and how it can actually increase stopping distances, but I couldn't find it. GX650EI + Velorex 700 (winter), '83 GL1000 (summer) '84 CB750SC Nighthawk (died - anyone need parts?)    Report

05-19-2008, 12:33 PM makenzie71 Joined on 03-30-2007 TX Posts 303 Re: brakes?! I almost died!  Sidecar Bob wrote: As I said before "Master cylinders for models with dual discs must displace twice the fluid for a given lever stroke than ones for single disc models. If you use a dual disc MC with only one caliper the lever will have less travel than it should and modulation of the brake will be more difficult." Someone else posted an explanaton recently of why this is a really bad idea and how it can actually increase stopping distances, but I couldn't find it. first you need to completely forget about the dual disc/single disc reference because it has absolutely nothing to do with the number of discs.  It's about the capacity of the calipers and only about the capacity of the calieprs. You are, vaguely, correct.  If you go too big, you will have problems.  For example, if you slap a 3/4" master and feed a stock Rukus caliper with it through a braided line your lever travel is going to be nil and you're going to blow seals.  If that were the scenario, I'd have to say you were correct. That's not the scenario, though.  What we're looking at is feeding an old-tech single piston caliper that, coinidentally, has a greater fluid capacity and lighter valving than the 4-piston Tokico calipers I currently run with an 11/16"  Brembo.  With a 1/2" or the stock 5/16" master cylinder on the old CX you have to pull the lever all the way to the grip to get decent stopping power.  A 5/8" master, even with a braided line, still allows full travel of the brake lever, and lessens the amount of work the rider has to do to adequately decellerate. Available from EssGlass ATV/Motorcycle Fabrication ~Preload adjusters (CX5/applicable): $55 + core caps ~310mm big brake kits (CX5/applicable): starting at $125 ~Left exit divorced exhaust: $225 for info email me!    Report

05-19-2008, 2:34 PM Sidecar Bob Joined on 03-02-2006 Kawartha Lakes, Ontario Posts 926 Re: brakes?! I almost died! Well, let's start with "With a 1/2" or the stock 5/16" master cylinder on the old CX". 5/16"? Where did you get that number? I have never seen a master cylinder with that small a bore. The stock master cylinder should be 1/2" bore. The dual caliper master cylinder should be 5/8". If you do the math you will find that a 5/8" circle has approx. twice the diameter of a 1/2" circle. This means that if you use a 5/8" master with one caliper it will only have half of the lever stroke that a 1/2" master would have. If the brake lines are in good condition and not 25+ year old stretchy rubber and the caliper and master cylinder are in good condition and there is no air in the system, the lever stroke from the point where the lever touches the piston to the point where the pads are fully compressed against the disc should only be about 1/2 of the distance between the lever pushed out against the stop and the lever touching the handlegrip. If the lever moves more than that something is not right. If you change to a master that pumps twice as much fluid and still have as much lever stroke as you should have, something is wrong elsewhere in the system and it will show up eventually. It is always better to make it work the way it should with athe correct master than it is to use a bigger one. When the pads are fully compressed against the disc, they can only produce so much friction, due to the pad and disc materials. Squeezing them harder won't make the bike stop faster - only better materials can do that, but they cost more and wear out faster so for normal on road use it is better to just not follow so closely. No matter how many pistons a caliper has it still has to move the pads the same distance in order for them to grip the disc. That's why dual piston calipers have smaller pistons. Multiple pistons simply allow the use of longer, narrower pads that can concentrate the grip nearer to the edge of the disc where the leverage is better. If you have a caliper with pistons on both sides of the disc they only need to move half as far as those in calipers with pistons on only one side - you are simply moving (as an example) 4 pistons instead of moving 2 pistons which in turn move the caliper against the back of the disc. BTW: have a look at what RodW says about 1/2 way down the page. http://choppercharles.com/cs/forums/36366/ShowPost.aspx "Valving"??? I have never seen a caliper with valves in it. GX650EI + Velorex 700 (winter), '83 GL1000 (summer) '84 CB750SC Nighthawk (died - anyone need parts?)    Report

05-20-2008, 11:22 PM Anonymous Re: brakes?! I almost died! <img src="/cs/emoticons/emotion-55.gif" />I[/i] did appreciate Makenzie61's comments. I agree that more is not always better. But a little more area in the master cylinder that results in slightly less lever movement and better feel is indeed better to some of us. Just to know what might work is good information in a pinch. To be fair, a larger MC piston puts more pressure through the stock calipers, and while it would reduce lever travel, it would also lighten the pressure required. Whether it reduces travel by half would depend on the lever's ratio, as well. If you want your bike to stop faster and you can already lock up the tire, you need better tires, not brakes. Of course, once you have better tires, you might well find your brakes aren't good enough. At which point, if you've already gone through the stock system, you will be looking at a larger MC before you can think about a different caliper.

05-22-2008, 1:24 AM Daniel45mpg Joined on 05-18-2008 Murrieta, CA. Posts 166 Re: brakes?! I almost died! Sidecar bob is really telling like it is bro. you can find these MC. but it's not easy. Post a link on this forum look on The big site E-lake (haha) so yeah what kind of brake line do ya have? are ya hearing that?? I think you want to hear that upgrading your master cylinder is a good idea. it may be. The best idea is to use the stock equipment with a braided steel brake line (black of coarse). with rebuilt caliper and mastercylinder. and throw in new pads just because this really is the most important system to you. After i did this i stop so fast 0n my 80cx500c it scares me. 1980 CX500C 1980 CX500D Reuse, Renew, Recycle.    Report

05-29-2008, 1:13 PM Jonathan_P Joined on 03-22-2008 Austin, Texas Posts 26 Re: brakes?! I almost died! So let me see if im understanding....bigger is not necessarily better wiht a master cylinder? Only problem is that i have been searching the net everyday and find nothing. Ive called every salvage yard in the state and cant find a MC for a single caliper '79 custom. What i keep on finding are MCs that are for dual caliper set ups and are 5/8. What should i do? keep on searching for the single caliper MC or go with the dual 5/8 MC? The rubbers on my bike are not the original and were replaced...not to mention that my rear brake set up is working fine and has good life left on it.    Report

05-29-2008, 3:33 PM Sidecar Bob Joined on 03-02-2006 Kawartha Lakes, Ontario Posts 926 Re: brakes?! I almost died! Any master cylinder from any bike will work. It doesn't have to be a transverse twin and it doesn't even have to be a Honda. The only things to worry about are: - the number of calipers it is designed to work with - the diameter of handlebar that it fits - the threads for the mirror - I can never remember which one it is, but one of the big 4 Japanese companies uses a left handed threar on one side and a right handed thread on the other. I have no idea what the master cylinder on my 650 came from. When I was putting my GL500 sidecar outfit together in 2000 I decided the original master cylinder was no good, so I bought one that was. It has no plastic reservoir at all, so it must be fairly old. When I got it I called the parts guy at the Honda dealer and told him I needed a 1/2" master cylinder kit and that I didn't know what the mc was from. The one he got me fit perfectly and has lasted well - it has now been on 3 winter bikes. GX650EI + Velorex 700 (winter), '83 GL1000 (summer) '84 CB750SC Nighthawk (died - anyone need parts?)    Report

05-29-2008, 5:42 PM tntchitwood Joined on 03-03-2008 Pine Knot, KY Posts 398 Re: brakes?! I almost died! Yamaha has the left handed threads. If you can read this thank a teacher. If you are reading it in English thank a soldier!    Report

05-29-2008, 5:55 PM Jonathan_P Joined on 03-22-2008 Austin, Texas Posts 26 Re: brakes?! I almost died! Which yamaha MC would work????    Report

05-29-2008, 6:49 PM drneo Joined on 10-20-2006 Duluth, MN Posts 212 Re: brakes?! I almost died! I'm using a Honda CBR600RR (as recommended by chopper Charles himself) with a set of stainless steel lines - works beautifully!! It doesn't have a mirror mount however... you may find one that is from a sport bike with a mirror mount. As sidecar bob referred to the mirror stem, it's Yamaha that uses the one that screws in the other way. 1982 GL500I - "Couchy" 52,000 miles down... 48,000 to go. www.trainwiththom.com