Topic: Bad front brake?

[alterego]

Hi everyone!
I'm pretty new to the forum as well as working on bikes so please bear with me!

Little over a month ago I picked up '78 CB550K which needs a bit of TLC... So I'm trying to work my way down the list of issues I've identified and one thing that I'm not sure about right now is the brakes.

Now I have heard/read that the stock front brake isn't all that great. I've never ridden a bike this age so I really don't know what to expect from it. When I got the bike the brake was locked up so my hubby and I took the caliper apart, cleaned everything up, bled the brakes and now they sort of work. What I mean is they are no longer locked up, the lever does not feel squishy (in fact there is A LOT of resistance, I cannot press it much before it won't go any further), the brake makes loud squeaky noises and slows the bike down (however the braking distance is HUGE, it doesn't seem to want to stop completely, just slow down and I always use the rear brake for this reason). Basically it makes me a little nervous riding around, especially in the wet because I feel if for whatever reason I need to brake hard, I'm screwed. (I'm in the UK, so it's wet very often indeed)

Have we done something wrong or is it really that bad as is?

Right now everything is stock as far as I can tell, rotor hasn't been drilled and the master cylinder / caliper are original.

So I guess what I'm asking is -
Am I expecting too much from the original brake?
How do I improve it, would a dual set up help at all / drilling the rotor?
Or should I look into replacing everything with something more modern?

Thanks!

Laura

[Rigid]

You still have some crud in there somewhere if the lever is hard like that.  The fluid is meeting resistance and not where it should at the caliper and disc.  Proper feel is a steasdily increasing firmness with a resulting locked up front wheel at full pull.  If it won't lock up the front wheel, even with stock parts, it needs more cleaning and possibly master cylinder seals.  Keep us posted.  Stock brakes aren't like a modern bike but they will stop you in a confident manner.

[trueblue]

Are your brake pads new or the originals, if you haven't replaced them yet I would do it, I don't trust well aged brake pads, they sometimes have a slick feel, feels like brake fade.  The brakes aren't good compared to a new bike but they still stop pretty good when functioning properly. The other possibility is your caliper slide may not be moving freely enough to allow both pads to apply even pressure to the disc.

[MoMo]

You need to rebuild the master cylinder also, and make sure the brake lines are clear...Larry

[alterego]

Thanks for the responses At least now I know something is definitely off.

Guess we'll take everything apart again and have another look. Good thing I stocked up on brake fluid already.

The pads look plenty thick still, not sure about whether they might be too slick though. I have a brand new pair lying around which I can try out.

I'll update once I've had a chance to try some of the suggestions.

[CoachDoc]

You need to rebuild the master cylinder also, and make sure the brake lines are clear...Larry

Strongly agree. Rebuild the MC and clean it thoroughly inside the cylinder. You won't believe what old precipitated brake fluid can gunk itself into.

[strynboen]

the  honda brakes work fine dry..its in rain they have a veakpoint with that stainles rotor...you have to break a littel to dry it before you drives fast..but its not that bad...just not as new bikes from today...but you have to break in new pads??? .. caliber moves i an radius not parealel..så break pats fits first 100% after some use..the first 750 have a raund point at piston to push on the pads..to make it push parelel on pads??..but it vas gone on later models that nylon thing came instead...hope you can understand it..im work on my english
is break pads the right vord??

[BeSeeingYou]

I recently rebuilt brakes for a friend's bike and his fork had a small leak that contaminated the pads.  Acted just like what you describe.

[scottly]

Drilling the disc will help the brake performance when wet. Unless the master cylinder is leaking, it's probably OK. A dual disc upgrade is the best way to improve the braking of these bikes, IMHO.

[cameron]

Like rigid hinted at... there are a number of subjective things, and a rather few objective things to look for. This is from my experience only on my 550.. oldtimers may disagree.

If your brake system is good, you should be able to do the following:
1. Lock your rear wheel easily.
2. Lock your front wheel in a terrifying way.
----- since 2. is terrifying, alternatively you can:
3. hold the entire weight of your bike on your front brakes on the steepest of hills OR
4. Hold ALL of your 1st gear torque with your front brake alone. (that is, spin your rear tire)

As you can see.. 'feel' and subtleties aside.. my TIRES are the weak point in my braking system. I can lock the brakes at any reasonable speed. You should be able to as well.

[scottly]

Like rigid hinted at... there are a number of subjective things, and a rather few objective things to look for. This is from my experience only on my 550.. oldtimers may disagree.

If your brake system is good, you should be able to do the following:

2. Lock your front wheel in a terrifying way.

I do disagree: the stock single disc setups are anemic at best, unless you have the strength of a gorilla. Rigid, in his other guise, doesn't believe in front brakes at all.  

[dave500]

if the disc looks shiny and polished deglaze it,remove it and use a large wet sharpening stone and work your way evenly around both sides of the disc till it looks machined.

[Gordon]

Like rigid hinted at... there are a number of subjective things, and a rather few objective things to look for. This is from my experience only on my 550.. oldtimers may disagree.

If your brake system is good, you should be able to do the following:

2. Lock your front wheel in a terrifying way.

I do disagree: the stock single disc setups are anemic at best, unless you have the strength of a gorilla.

I've locked up the front brake in panic stops on both my 550 and 750, and I'm definitely no gorilla. 

[Rigid]

Like rigid hinted at... there are a number of subjective things, and a rather few objective things to look for. This is from my experience only on my 550.. oldtimers may disagree.

If your brake system is good, you should be able to do the following:

2. Lock your front wheel in a terrifying way.

I do disagree: the stock single disc setups are anemic at best, unless you have the strength of a gorilla.

I've locked up the front brake in panic stops on both my 550 and 750, and I'm definitely no gorilla.

+1 no gorilla grip here, just properly functioning OEM brakes.  They are adequate, it is the tire that is the limitation.

[cameron]

I also have no gorilla strength, and my stock brakes (well.. SS lines) can perform to the above conditions.

[BeSeeingYou]

Functioning properly I have not felt the stock brakes are inadequate.  The single disc front and rear on my 79 XS650 are noticeably better than my Honda 750F1 but they are next generation.  Of course they won't match up to a modern bike but to me it's not worth the trouble, expense, and added weight.

[MoMo]

I agree, stock, properly functioning brakes are more than adequate for normal riding...Larry

[scottly]

I decided that a single disc was inadequate after what would have been an aggressive stop from 65 MPH with duals, rapidly became a panic stop with a single. The front brake, and knowing how to use it is the most important safety feature of any motorcycle ridden on the road, IMHO.   

[nancy]

It is not necessarily "normal riding conditions" that will hit you. It is the abnormal - or the event that is fairly normal - but not often encountered - so you misjudge a little. For example - on my K2 750 with the wife on the back, coming through a winding and downhill section of country road - came to a steep descent into a hairpin curve - with extra weight on the back - I had less brakes than I felt I needed and had to abort the turn and grind to a halt facing the cliff - instead of taking a nosedive into it. Lucky no cars were behind me. I have new sintered pads and a fully rebuilt master cylinder. Only the lines remain as original - I might get better stopping from braided...but never got a reply back from repeated requests of Pampadori (I think that's his handle) to supply me those. So gave up.
I find the rear drum to be a better option than my front disk. A combination of both is more than I need for normal daily road riding.
Downhills, 2-up - into hairpins...I'll go home and get my Sprint ST.

Regards
Mark

[somesuch]

... I have new sintered pads and a fully rebuilt master cylinder. Only the lines remain as original - I might get better stopping from braided....

Regards
Mark

Mark, where did you get those sintered pads?

Brake lever is too far away and too firm on all of my CB750s, but locking the front is possible with all STOCK parts

--Nick

[Hush]

Even my mate that does the warrant on my CB650 can't believe how bad the brakes are and they are twins! He reckons I gotta give it a week's notice if I'm gonna do an emergency stop.
Seriously after playing with the bikes my son rides our old Honda ones are stoneage, even though my system doesn't leak it is still a worry for hard stopping, braided lines would stop the sideways squish in the lines themselves, might get some new pads from David Silver when I order my cam chain adjuster in New Year (unless Santa drops one down the chimney).
The 1982 650 Custom I sold had much superior braking, so much so that when they did an epic fail they nearly cartwheeled me through a set of traffic lights, but they were the last of the SOHC4 bikes so the stuff was improving all the time.

[Duanob]

Go with stainless steel brakelines that will be your best brake upgrade for the 550. try this: Grab the brake line then grab the brake lever and see how much old rubber expands. That hydraulic energy is being diverted from your pads and rotor and wasted into the rubber walls of your old lines. I can't even feel the SS lines expand whatsoever and braking in the front is definitely better. But it will never be like a modern bike.

[cameron]

I decided that a single disc was inadequate after what would have been an aggressive stop from 65 MPH with duals, rapidly became a panic stop with a single. The front brake, and knowing how to use it is the most important safety feature of any motorcycle ridden on the road, IMHO.   

I certainly agree that the stock setup is weak.
But in re: to the original post... it seems like he can't lock his front brake... which means it is not tuned correctly.
He should tune it up first . . THEN decide if he needs dualies for his style of riding. Maybe he does. Maybe not. I dont.. but I ride like a girl

[BeSeeingYou]

The two bikes of mine I have ridden have single discs front and rear and like I said they do the job fine.  Now I am working on my 75 XS650 and that one will be my first ride with a drum on the rear and an first generation front disc.  Maybe in the spring I will have a change of heart....we will see.

I still think alterego has contaminated pads.  MC should be rebuilt and new brake lines too.

[scottly]

I decided that a single disc was inadequate after what would have been an aggressive stop from 65 MPH with duals, rapidly became a panic stop with a single. The front brake, and knowing how to use it is the most important safety feature of any motorcycle ridden on the road, IMHO.   

I certainly agree that the stock setup is weak.
But in re: to the original post... it seems like he can't lock his front brake... which means it is not tuned correctly.
He should tune it up first . . THEN decide if he needs dualies for his style of riding. Maybe he does. Maybe not. I dont.. but I ride like a girl

Uh, reread the first post: he is a she...