Front brake lever effort

[Artie]

It takes a real hard squeeze to get decent stopping power,but last nite riding with wife as passenger (120 lbs) for first two up riding ,brakes are poor at best only because of lever effort required,everything's new pads ,caliper rebuilds etc. etc.the pads could be the issue can't remember brand but packaging looked older as I can recal,E Bay buy along with all the usable stuff arriving during rebuild,maybe EBC or other top quality pads mfg. would do the trick???? Discs are fine,clean oil free,
I heard that a Kawasaki ZX-14/C-14 front master cylinder is the fix,or was that just a fairy tale dream .brake effort way to high all modern bikes are 2 finger affair or is that what it was in 1979???
Any and all help appreciated in advance.......

[steve murdoch icoa #5322]

Artie, it could be the pads have glazed.
Seeing as they are new i would take some fine sand paper to the pads to scuff them up a bit.
I bought inexpensive generic pads for my '81 and threww them in the bin after a couple hundred miles. The grip was poor and they squealed.
Been using EBC since.
Don't know about the zx-14 m.c.

[daves79x]

Lever effort should be moderate at worst to get good stopping power. New pads have to bed in for several hundred miles to have the best effect. Don't know what you're used to, but my CBXs stop as well, with only a bit more lever effort, as my Triumph Tiger and GL1800. Did you get new brake lines as well? Half of your lever effort might be in expanding the 35 year old lines. And getting the front system completely bled can be a nightmare.

Dave

[NobleHops]

I learned more about brakes working on my CBX than my other 8 motorcycles combined, mostly from Dave.

Steve makes a good suggestion, I'd add that the rotors can get glazed too, and some emery on the rotors along with a good scuff of the pads on a flat block might give you a reset, but that is going to require bedding them in all over again, which does take some time.

The biggest revelation in my Brake Quest was the value of strapping the lever halfway to the grip and leaving it that way overnight. More than any other technique, that has restored a firm lever and good braking power when every other technique has been exhausted.

The operative effect of the mod you are referring to WRT the Kawa master is a larger bore of the master cylinder. Randakk swears by this too, and sells a kit that doesn't look particularly correct, but is reputed to work well.

I would (did) take the advice offered in this order:

Try a bleed as described.

Inspect the brake lines - if they are original or close to it, punt. An eBay vendor called Cruzinimage sells a front set that is a ringer for stock for very short dough or better yet ditch those and the splitter altogether and go with a two-line braided steel setup from Spiegler.

Sacrifice a chicken or better yet a goat if you have one.

Remove the pads and deglaze them with a sheet of 80-grit on a piece of quarry tile or plate glass.

Deglaze the rotor with emery or a ball hone in a drill.

Clean it all up, give it 200 miles with some super-hard stops done to bed things in, and report back.

N.

[kbart1]

hey guys

FYI I bought one of those harbour freight brake bleeders that you hook to your compressor and it works awesome. I have the same set-up Nils mentioned on my '81, the spiegler two line set-up WITHOUT the splitter and using the harbour freight tool was a breeze and I have a good firm lever.

thx
kent

[daves79x]

I know for sure Randakk's, and to my knowledge (not absolutely positive), most replacement master cylinders guys use are all 5/8 bore - the same as the stock CBX. 5/8 is the production standard for twin disc brakes since just after the first Gold Wing days. The problem is these are 30-35 year old units that may have some pitting and wear and most guys just slap a new rebuild kit in them and go. And mushy brakes with bad feel result, as well as from old lines and calipers not properly cleaned and serviced.

If you really prep the front master cylinder (a good honing with Scotchbrite works well), install a new kit, new lines (Spiegler are my favorite also), properly prepped calipers (including cleaning and lubing all sliding pins), you will have the basis for good front brakes. You also need to Scotchbrite the rotors.

All that's left is to properly bleed, which can be a PITA, as Nils describes. I've described this many time before. Install loosely all front brake components. Tighten all banjo bolts where you want them. Then remove the entire system intact, with the m/c still attached to the bar, and lay it out horizontally on a large box propped up on saw horses. You have to take the right headlight bolt out and fish the line out of it's position there. Once everything is laid out pretty flat, then use a Mity-Vac to bleed each caliper, rolling each one around as you go. Rotate the splitter as well and in 5 minutes you'll have all the air out, and use way less than a pint of fluid.

Reinstall the brake system and pump out the caliper pistons. You should have excellent lever feel right away, but just for good measure, do as Nils suggested and tape the lever back just enough to expose the bleed hole, turn the handlebar to the left and leave overnight to allow any bit of air left to escape.

This procedure works for the Pro-Links as well - you can fish the calipers and splitter from behind the fairing.

I should include a note here about brake fluid also, and have been meaning to update some of my recent brake fluid comments. Over the last 2 or 3 years, I've been installing DOT 5 brake fluid in all my CBX brake rebuilds. I've done probably 5 or 6. Most had all-new rubber components (a mixture of aftermarket and OEM Honda). But some original parts were used as well. I clean every component very well and flush the brake lines (new or used) with alcohol, as well as soak the rubber parts in alcohol. I've not had a problem with the DOT 5 UNTIL recently. The last restoration you may have seen the pics of has been a nightmare in the braking department. The rear is fine with the DOT 5. But the front is another story. I've had it apart 3 times, trying different components and every one of the m/c rubber parts I tried swelled from the DOT 5 and stuck the m/c. The caliper seals swelled as well and they were new Honda OEM parts. I finally gave up and cleaned the entire system again and went back to DOT 3/4. Front works great now. Some of the swelled parts never did regain there original shape and had to be tossed. I then naturally redid the rear system since the new owner likely won't care for DOT 4 in the front and DOT 5 in the rear.

Moral of the story - I haven't a clue. DOT 5 worked in 4 or 5 other bikes, including my original '79 brakes just redone last fall. But certainly not this one. That's my story, take from it what you will.

Dave

[EMS]

I should include a note here about brake fluid also, and have been meaning to update some of my recent brake fluid comments. Over the last 2 or 3 years, I've been installing DOT 5 brake fluid in all my CBX brake rebuilds. I've done probably 5 or 6. Most had all-new rubber components (a mixture of aftermarket and OEM Honda). But some original parts were used as well. I clean every component very well and flush the brake lines (new or used) with alcohol, as well as soak the rubber parts in alcohol. I've not had a problem with the DOT 5 UNTIL recently. The last restoration you may have seen the pics of has been a nightmare in the braking department. The rear is fine with the DOT 5. But the front is another story. I've had it apart 3 times, trying different components and every one of the m/c rubber parts I tried swelled from the DOT 5 and stuck the m/c. The caliper seals swelled as well and they were new Honda OEM parts. I finally gave up and cleaned the entire system again and went back to DOT 3/4. Front works great now. Some of the swelled parts never did regain there original shape and had to be tossed. I then naturally redid the rear system since the new owner likely won't care for DOT 4 in the front and DOT 5 in the rear.

Moral of the story - I haven't a clue. DOT 5 worked in 4 or 5 other bikes, including my original '79 brakes just redone last fall. But certainly not this one. That's my story, take from it what you will.

Dave

I hope all this does not open another can of worms here, as we had these fruitless discussions about the pros and cons of DOT5 before.
I do acknowledge, that there are some advantages to DOT5, the main one being that it is safe for paint, but I use DOT5 only in one vehicle I own. A "for DOT5 converted" 1970 Mercedes 280SL. This car got all new brake lines and calipers with DOT5 compatible seals and O-rings. It actually sits more than it is being moved and that is fine. When it is being moved, it is being driven lightly and nothing is being asked of the brakes that brings them close to their performance capability.
DOT5 is poor in the performance area, that's why there are NO ABS applications in the vehicle industry that I know of, that use DOT5 and no serious racer uses DOT5.
DOT5 also needs to be handled very carefully when originally filled. As it picks up air when it is being shaken or splashed, you will end up having excessive air in the brake system. The notion that DOT5 prevents corrosion is a myth. As there is some air in ANY brake system, no matter how careful you are - and you do not fill under vacuum - moisture will fall out through condensation during operation and as DOT5 is not hygroscopic, like DOT 3 and 4, this moisture will settle at the lowest point in the system, usually the calipers and will cause corrosion there. This is the main reason, why all experts recommend to change DOT5 also on an annual basis for any vehicle that is operated regularly. This negates the often touted DOT5 advantage of being "maintenance free". I think everybody should use what they think is best for them, but I offer the advice to seriously check around and find out what are the ups and downs of the various DOT spec brake fluids and them make an educated decision.

[daves79x]

I should have made it clear - I'm not praising ANYTHING about DOT 5 except it's total compatibility with that freshly painted tank and fender and the freshly painted master cylinder and calipers. DOT 5 performance or lack thereof means absolutely nothing on these old things, compared to DOT 4. That was my only reason for switching and I was just updating everyone on what I found.

Dave

[EMS]

DOT 5 performance or lack thereof means absolutely nothing on these old things, compared to DOT 4. Dave

To an extend I do agree with this. But if I read it right, the original post was clearly about brake performance or lack thereof...

[daves79x]

I think that's cutting it way too fine, Mike. I'll contend that if everything else is right with a CBX brakes, you'll notice no difference using DOT 4 or 5, especially the way these are ridden these days. The original poster has a ways to go before worrying about whether to use DOT 4 or DOT 5.

Dave

[EMS]

I know what you're saying, Dave. But if somebody is critical enough to notice a difference between rubber brake lines and braided steel lines on a CBX, he will recognize the difference between DOT4 and DOT5.

[daves79x]

Old rubber lines vs steel - big difference. New rubber vs steel - not much.

Dave

[Artie]

I believe I have no bleed issues and have Stainless lines,and rock hard lever with short stroke just NO power need strong hands to really haul it done,2 fingers on my Kawasaki C-14 could do a Marquez sloppy if I had the skill!!
I'll try scuffing pads ,emery clothed rotors when I built it 8 mos. ago and report back but as of now the brakes stink!
My bleed was done with gravity and patience,little wiggling at bars bubbles always rise,empty system to hard lever takes 20 minutes ,tap calipers and M/C with soft mallet helps.
Guys at my local shop power bleed everything ..I'm old school and old school cheap!!! Go slowly fill master cylinder open all bleeders with clear tubes in 2 empty 6oz coke bottles in a few minutes fluid will slowly fill system wiggle tap add a little juice PATIENCE bleed slowly after clear fluid fills tubes.

[CBXTRA6]

Artie,

this is what used on a restored 79 as a "rider"

[/img]



Found the M/C on EBay , brand new for a little over 100 bucks, OEM MC on Honda Hornet, with a set of braided
steel lines, and DOT 4 (Ah Ah) , it works really good, 2 fingers operation. The key is to get the right bore.
16 mm (5/8") . It squeezes well the double pistons calipers and vented pro link disks.

[Artie]

I have single piston calipers and stock rotors it's a 1979 model,used #65 grit to deglaze pads emery clothed rotors much better as good as it's going to get I'm afraid for this equipment can live with it now,what's the best way to bed in brake pads heard so many variations???