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Cure For Pulsing Brakes...

Discussion in 'Motorcycle Talk' started by Tonga2, Apr 27, 2014.

  1. 9/10 pulsing brakes are a stuck/dirty piston in the caliper, not a warped rotor.
     

  2. Very true but the last handful I've come across have been warped rotors
     
  3. Really? That's interesting. I'm a auto tech and on cars it's pretty much 10/10 a warped rotor. Why is it different on bikes?
     
  4. No your right it usually the rotor, bikes have a thin disk versus a cars thick rotor .
     
  5. 99.9% of all bikes have front rotors like in the video. 2 piece "floating" design. When they stop "floating" you essentially have a warped rotor. Make them "float" again and all is well.

    99.9% of cars do NOT have floating rotors. Just solid hunks 'o iron. When they warp, they pulse. Resurfacing or replacing are the only solutions.
     
  6. I don't have anything to back it up but I think pad wise and how hard they are used wise, car brakes are much easier to overheat and then also more likely to get crazy cooling cycles from car washes, rainy days, etc than bikes are.

    Either way, check the floating design and clean your pistons first before ever replacing a rotor on a bike. It'll save you a lot of money in the long run even if eventually one needs a rotor.
     
  7. cjohns

    cjohns sctnabt

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    Point is...this is a cheap and easy fix. Certainly something to try/eliminate as a source of pulsing. Great post!
     
  8. That's what I was thinking too but I see the point why not check the other stuff first if it's easy and cheap.
     
  9. Good vid, thanks for the post.
     
  10. son has a gsxr with symptoms. i will attempt this before he goes all in on new rotors.... more to follow...:popcorn:
     
  11. Great video! Thanks for posting. I shared it over on SVRider.com
     
  12. hmm...I'm not so sure this would be a good idea on the Z1000 rotor. I have a used "bad" rotor i tried this on and the problem is not on the front side of the rotor, but the back side. Totally different backside and i get the feeling you would pinch this even tighter...front side had a nice wide flat surface, the back side is different and appears sort of flanged and thin. Read: ok i vice this thing and it gets even tighter *i only tightened hard enough to spin the bobbin, no more!*...i can just imagine how this would wreak havoc when you bolted it back together. Since the used rotor is not good i tried this and the "bobbin's" were just as hard as when i started, maybe a little easier, but NO WAY you can spin w/ your fingas HONDO! multiple sprays of carb cleaner and spinning w/ the bolt and nut....ant! not gonna do it.

    So i would consult an expert or buy another set of rotors...be careful.

    Maybe this works for that particular model, but you might do more damage than good.

    Shi* is expensive.
     
    Last edited: Apr 28, 2014
  13. Great post, will check mine tonight
     
  14. You make a good point. Just realized my EBC's have square buttons. Last I checked squares aren't supposed to spin...

    Still a great video for round buttons!
     
  15. "Pulsing brakes" can mean a few different things:

    Different answers to these questions mean different issues with your brakes:

    Is the lever pulsing? If the lever is pulsing, probably warped rotors.

    or

    Are your stops pulsing, as in you feel differing rates of deceleration as your wheel rotates. This will/can occur without the brake lever pulsing in your hand. If this is the case, then it's more likely a friction issue, not a warpage issue.

    Also, does the bike pulse more as you feather off the brakes? Or is the pulsing uniform no matter how much lever pressure you apply? Is the pulsing worse with greater lever pressure? Increasing pulsing as you feather-off the brakes is a friction issue. Uniform pulsing, or worse pulsing with greater lever-pressure could mean warping or problems with the hydraulics or pistons.

    Gummed-up "float" buttons will solve a problem, but won't solve others. Floating rotors are to allow for expansion of the rotors as they heat. Is your pulsing the same when the bike/brakes are both cold and warm? Then the issue is probably not your float-buttons. Can't hurt to clean them though. But as mentioned above, there are better ways to clean your "bobbins" than shown in the vid. My advice is to hose them down with brake-cleaner, then blast with compressed air. Repeat as necessary until the buttons/bobbins rotate easily. No trauma to the hardware. Do this with the rotors off the bike. Clean the rotor's swept surface with acetone or denatured alcohol before you re-mount the rotors.

    Another cheap and easy action you can take: Have your rotors bead-blasted. One frequent issue is uneven build-up of pad material on the rotors. This can cause differing friction coefficients along the rotor, leading to pulsing brakes (and not a pulsing lever). Bead-blasting takes this off.

    Uneven pad-material build-up occurs due to improper braking technique, such as keeping the calipers clamped onto a hot rotor at a stop (this can also cause warping) or by failing to properly bed in new pads and/or a clean rotor. It can also occur due to the metallurgy of the rotor.

    Some rotors are just flawed, come from the factory with uneven tempering or other subtle manufacturing flaws that contribute to uneven coefficients of friction alone the rotor. If this is the problem, then annual bead-blasting can put a new face on the rotors. The motor-head shop I use bead blasts my rotors for $20 total, for two front rotors off the bike. It's like getting new tires. Nothing wrong with my rotors, but this spring-cleaning just makes the brakes better., better feel, just a bit more bite.

    Rotor-hone devices can approach the cleaning of bead-blasting, but bead-blasting is best in terms of a fresh surface on the rotor.

    Just my .02 (from the .02 of a few very smart motor-heads)
     
    Last edited: Apr 28, 2014
  16. My bobbins dont rotate. No pulsing levers or brake issues of any kind, they
    are full floating rotors. What gives?

    Sent from my LG-D801 using Ohub Campfire mobile app
     
  17. I did the procedure in the video. I couldn't rotate the rotor buttons with my fingers beforehand, but now they are nicely freed up and the rotor is much more free-floating than before. It took about 10 minutes or so. Time well spent, for sure.

    IMO, rotating the buttons is the only way to get the corrosion/dirt/crud worked out of the contact surfaces unless you have the one-in-a-million, super secret solvent that dissolves all of that stuff. <(not happening!). Brake cleaner can flush away the corrosion/dirt/crud, once it's been physically loosened up by rotating the buttons.
     
  18. Thanks for the great information!! My ZRX has a terrible front brake pulse, and it's not at the lever, but it does adversely affect the braking and stopping- the braking during a stop is almost jerky.

    It's most noticeable at mid-pressure. Light pressure has a barely noticeable pulsing, mid-pressure is where it's worst, and then under heavy braking it totally disappears.

    I think some cleaning is in order, perhaps followed by bead blasting. I already have a spare rotor sitting on the workbench, but if I don't need to mount it, all the better.
     
  19. Wow cool I had no clue about this. Thanks for sharing.