Topic: The best my brakes can be

[francesb]

Hey all,

So, a month or so ago I rebuilt my brakes and master cylinder, added a stainless steel brakeline. Then, took the bike out for a ride this weekend (well, ok, 730 miles over two days, through VT, it was amazing) and my brakes still SUCK.  I found that no matter how much I squeezed and slammed, the bike was *not* going to completely stop on a hill. I know the CB is not supposed to have good brakes, but I need something better than this.

I understand my options are adding a second disc, and "drilling the disks." With which will I be happier? I've also read about replacing the front end with a Goldwing front end (and its better brakes), but I just spent that money on the brake parts and lines. At the same time, I do need to rebuilt my front end....if I must go for the Goldwing option, what year Goldwing does one use.

But hey, on the bright side,, that was a long ride in really hot weather, and the bike performed beautifully. I only needed to make one duct tape repair.

thanks in advance.
frances

[Chris Liston]

I find that I just have to adjust my riding.  No matter what you do its not going to brake like a modern sportbike will.  Learn your bike and the do's and don'ts.  Mine stops, now much better with stainless lines up front.  It is improved but I don't go crazy on the brakes when riding most of the time.  Not sure on Goldwing options.  You could go dual disk and get a CB750 master and caliper.  Probably still be able to use the one side of the stainless and just order the matching lines for side 2.

[Matt at PSB]

A 1979 or 1980 DOHC CB750F complete front end will slide right into 1974 or later triple clamps. That is the easiest way to get brakes that work.

Matt at PSB

[francesb]

Matt

I find that I just have to adjust my riding. No matter what you do its not going to brake like a modern sportbike will. Learn your bike and the do's and don'ts.

I've never ridden anything but vintage, and its not like i'm comparing my bike to an SV or something....Is it really unrealistic to expect the bike to stop on an incline? i'm planning some long rides through mountain ranges....

A 1979 or 1980 DOHC CB750F complete front end will slide right into 1974 or later triple clamps. That is the easiest way to get brakes that work.

i have a K3. is there any hope for me?

[Einyodeler]

Does it feel spongy , are you sure there is no air in the system?
On my `72 500 I can lock up the front brake if I need to.

[TwoTired]

Hey all,

So, a month or so ago I rebuilt my brakes and master cylinder, added a stainless steel brakeline. Then, took the bike out for a ride this weekend (well, ok, 730 miles over two days, through VT, it was amazing) and my brakes still SUCK.  I found that no matter how much I squeezed and slammed, the bike was *not* going to completely stop on a hill. I know the CB is not supposed to have good brakes, but I need something better than this.
frances

I think there is still something wrong with your brakes.  The the 750 is few pounds heavier than the cb550.  But, my 74 is in full dress and I can squeal the front tire with the brake.  And, it would have be a really steep hill to not be able to stop.  Are you sure you don't have oil or silicone on the pads?
Do you run out of travel at the lever?  Do you feel your hands aren't strong enough?

Did you replace all the rubber brake lines or just one?
Does your disc get hot just rolling around indicating too much drag from the pads and a possible retraction problem?
Are you using the stock pads, or aftermarket?

[Matt at PSB]

Hey all,

So, a month or so ago I rebuilt my brakes and master cylinder, added a stainless steel brakeline. Then, took the bike out for a ride this weekend (well, ok, 730 miles over two days, through VT, it was amazing) and my brakes still SUCK.  I found that no matter how much I squeezed and slammed, the bike was *not* going to completely stop on a hill. I know the CB is not supposed to have good brakes, but I need something better than this.
frances

I think there is still something wrong with your brakes.  The the 750 is few pounds heavier than the cb550.  But, my 74 is in full dress and I can squeal the front tire with the brake.  And, it would have be a really steep hill to not be able to stop.  Are you sure you don't have oil or silicone on the pads?
Do you run out of travel at the lever?  Do you feel your hands aren't strong enough?

Did you replace all the rubber brake lines or just one?
Does your disc get hot just rolling around indicating too much drag from the pads and a possible retraction problem?
Are you using the stock pads, or aftermarket?

The correct answer to any or all of these questions would greatly improve your OEM braking. Oil on the pads & air in the system would be my first guesses. Making the OEM period brake work to its fullest would be what I would do first before upgrading to later braking systems. These bikes are three decades old & retaining their "vintage" state is of some value.

Only when the full potential of the vintage systems is reached & exceeded should you go further.

Matt at PSB

[cben750f0]

if you have evr.. and i mean ever got brake fluid on the pads, they will never be the same... i got some on my pads, and the bike became an 245kg, unguided weapon... no amount of linishing could get rid of it, bought ne pads, and away we went... good brakes again... just a thought..peace

[kghost]

Both My 72 750's are capable of locking the front tire with the stock brake.

I will admit that it takes a pretty big grab of the lever to do so. But it will do it.

I think you have some issues to investigate.

[Lumbee]

...take an afternoon, find a buddy and bleed the brakes.  Sounds like to me you have air in the system.  No, cb's won't break like moder sport bikes, but you should absolutely be able to lock or come close to locking the front break.  Keep digging and you will find the problem.   

[low-side]

My 75 750K now has 3 discs and stops about as well as anything I have ridden.  I have 2 drilled rotors up front with the calipers mounted on the rear side of the fork and the rear is off of a 550K.  Nothing I've done cannot be reversed, so stock status is easily regained.  You may try using Bendix (or Tuff Stop) pads before going to all that work though; those pads are far better than stock.  Good luck.

[Tim.]

My 75 750K now has 3 discs and stops about as well as anything I have ridden.  I have 2 drilled rotors up front with the calipers mounted on the rear side of the fork and the rear is off of a 550K.  Nothing I've done cannot be reversed, so stock status is easily regained.  You may try using Bendix (or Tuff Stop) pads before going to all that work though; those pads are far better than stock.  Good luck.

your rear disc brake is off a CB550K?  do you have pics of this?

[Chris Liston]

My 75 750K now has 3 discs and stops about as well as anything I have ridden.  I have 2 drilled rotors up front with the calipers mounted on the rear side of the fork and the rear is off of a 550K.  Nothing I've done cannot be reversed, so stock status is easily regained.  You may try using Bendix (or Tuff Stop) pads before going to all that work though; those pads are far better than stock.  Good luck.

your rear disc brake is off a CB550K?  do you have pics of this?

Must be a nice custom rear as K's or F's for that matter in the 550 came with rear disks.  Wish the did.

[francesb]

Yes, I clearly have some issues to investigate.

I have aftermarket pads on the bike--can't remember the brand, but I have a good parts guy, and think they're good quality. I do most of my wrenching myself, but my brake rebuild was bartered, and they were done by a very talented mechanic with 25+ years experience, so I'm going to assume he didn't get brake fluid on the pads. Left to my own devices, I'd *totally* get brake fluid on the pads.

Brakes were done about 900 miles ago, and at this point I'm assuming they need some follow up adjustment and attention. They've really only just started bedding. I'll bleed them this weekend...

In a cool irrelevant aside, NYS still had the CBCHIK plate available, so I ordered it. Heh.

frances
CB750 K3

[TwoTired]

900 miles is usually plenty to seat in the brakes.  Assuming of course they were frequntly used. 

When I did my brake improvements on my 74 CB550.  I also tried aftermarket pads.  EBC, if I remember correctly.  The did not stop as easily as I liked.  So, I got some OEM from Honda.  These worked better, although the pad composition sure looked different than what was originally on the bike.  I, reluctantly, did some abrasive scrubbing on the front rotor.  Scotch brite at first, then I got into it with sand paper and put a crosshatch pattern on it.  I also filed off the face of the pads a bit. They improved a great deal, and in a week I was able the squeal the front tire.

I was told that the pad material embeds particles in the rotor.  And, particles from different pads don't always have compatible friction characteristics, actually building up gas bubbles that don't have much friction at all.

FWIW

[MRieck]

Bead blast the rotors first!! Wrap teflon tape around the bleeder bolts and start from there. I use Dunlop pads on mine BUT blast the rotors first.