http://www.siriusconinc.com/default.asp
I've been quite happy with their parts. Good luck.
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.
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.
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.
Sidecar Bob wrote:We're talking about a '79 custom. It has a single disc so 5/8" bore master cylinders are not applicable.
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.
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.
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.
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.
Jonathan_P wrote:Which yamaha MC would work????
Any Honda, Suzuki or Kawasaki master cylinder for single caliper and 7/8" handlebars (some of the cruisers have 1" bars) will work. The reservoir might not sit at exactly the right angle to be level with the Custom's handlebars, but unless it's really off level it shouldn't matter that much.
You can also use a similar Yamaha master cylinder, but you would need to replace your mirrors with Yamaha items because Yamaha mirrors have a left hand thread on the right hand mirror that screws into the master cylinder.
Interstate or naked?
If it's an Interstate have a look at mirrors for a GL1100 GoldWing - they're the same.
If it's naked see what your local dealer has in stock that you like the look of.