Doomking Posted September 20, 2017 Report Share Posted September 20, 2017 HelloI just noticed that when I come to a stop at slow speed the brakes are "pulsing" like the rotor might be warped, however at any other speed say over 20 mph up to 100 plus, the brake feels solid with no pulsating feeling whatsoever, so to speak.So if the rotors were warped wouldn't it pulsate at any speed? Why only at slow speed when I come to a stop light?Also I have no feed back of any kind to the brake lever just a "pumping " motion of the forks as I come to a stop.Pads look in good shape as well as the rotors from a visual inspection.Should I replace pads first see if it cures it or replace rotors?Any idea?Thanks for the help. Quote Link to comment Share on other sites More sharing options...
JustinNck1 Posted September 20, 2017 Report Share Posted September 20, 2017 Have you tried cleaning the rotor buttons? Brake dust builds up and can cause the buttons to not spin freely. It will feel like a warped rotor. Quote Link to comment Share on other sites More sharing options...
Bubba Posted September 20, 2017 Report Share Posted September 20, 2017 Could be warped rotors--many big heavy superbikes are susceptible to overheating their rotors if subjected to high speed stops--but it might be something as simple as a rough, dirty or corroded spot on one or both rotors. Before you commit to spending $$$ on new parts, try using some brake cleaner and a fiberglass or copper scouring pad to thoroughly clean the surface of both rotors. Some folks use steel wool, but I've heard you can get some residue left from the steel pads that will create rust on the rotor surface. Quote Link to comment Share on other sites More sharing options...
Killer_kaw Posted September 20, 2017 Report Share Posted September 20, 2017 As mentioned above clean rotors. Then clean up the pistons while you're at it. Uneven pressure from sticky pistons will sometimes give a low speed pulse. Quote Link to comment Share on other sites More sharing options...
blue03636 Posted September 20, 2017 Report Share Posted September 20, 2017 We have noticed something like this and it was the front suspension. May try opening or closing your rebound a little to see if it helps. Probably close if you haven't changed the fluid in a while or ever. Quote Link to comment Share on other sites More sharing options...
Doomking Posted September 20, 2017 Author Report Share Posted September 20, 2017 Checked the rotors and they are clean. buttons are all stuck with no play.. I am bit confused here. Is the rotor supposed to be floating on those buttons? In other words should I have any kind of play when I try to push the buttons or spinning it? right now both rotors have those round buttons all firmly attached to the rotors both sides. Quote Link to comment Share on other sites More sharing options...
durk Posted September 20, 2017 Report Share Posted September 20, 2017 Every time I've ever had pulsating it has come down to a warped rotor. I can't say for sure if that is your problem, but it would be my guess. Quote Link to comment Share on other sites More sharing options...
motocat12 Posted September 20, 2017 Report Share Posted September 20, 2017 i had bent caliper bolts cause it once. there's fixed. floating, and semi floating. On some bikes as a last resort people will bend the spring washers out away from the rotor. Quote Link to comment Share on other sites More sharing options...
mello dude Posted September 21, 2017 Report Share Posted September 21, 2017 (edited) 4 hours ago, Doomking said: Checked the rotors and they are clean. buttons are all stuck with no play.. I am bit confused here. Is the rotor supposed to be floating on those buttons? In other words should I have any kind of play when I try to push the buttons or spinning it? right now both rotors have those round buttons all firmly attached to the rotors both sides. A longtime geek mechanix trick is to find bolt and nut that will fit in the hole in the buttons and tighten them up and rotate nut/bolt/button combo with socket wrench. Clean the shit out of it with brake cleaner. - Those buttons are supposed to be moveable..... Edited September 21, 2017 by mello dude 1 Quote Link to comment Share on other sites More sharing options...
Tonik Posted September 21, 2017 Report Share Posted September 21, 2017 15 hours ago, Doomking said: Checked the rotors and they are clean. buttons are all stuck with no play.. I am bit confused here. Is the rotor supposed to be floating on those buttons? In other words should I have any kind of play when I try to push the buttons or spinning it? right now both rotors have those round buttons all firmly attached to the rotors both sides. Just to clarify, the buttons should be free so you have movement of the rotor side to side. That lets the rotor float so it centers in between the brake pads. There should be no rotational movement. Quote Link to comment Share on other sites More sharing options...
Helmutt Posted September 21, 2017 Report Share Posted September 21, 2017 Heat will make a difference too. If the rotor seems to have a little movement when cold, it will tighten up firm once hot from use.....so check them cold. I had an '08 ZX14 for about 7 years. The stock front rotors blued from heavy braking, but never had an issue with pulsation like your talking about....even after 24k miles and a few trackdays on sintered padsets. For starters, I'd put the bike on stands, pull the front fender for a clear view, and watch how it behaves while you spin the front wheel by hand.....maybe have a friend slowly pull the lever a few times while it's spinning too. Quote Link to comment Share on other sites More sharing options...
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