pulsing rotors

[Dustproof]

I had vibration from the front brakes, I had to suddenly do a very hard stop and then I didn't have any vibration.  After a few hundred Km's I started getting the Vibration back again, I thought "OK it worked last time" so I did a hard stop again on purpose and fixed it again.  Hmmm me thinks, the factory brake pads must be soft as and are leaving a residue on the disc.  I think I will change them out soon for a better quality pad.

Anyone got any good ideas on manually cleaning the rotors?  I guess they will clean off in time but I would like to start a fresh.

Noel

[VirginiaJim]

This is one way....

http://zggtr.org/index.php?topic=566.0

I used a rotor hone in a drill and used  low rpms to scuff them up.  I took my wheel off and put it in a jig so that they were horizontal.  Brian is a vertical kind of guy, though, and likes to see things spin.  After I did the outsides, I removed the rotors from the wheel and did the inside surface.  I just remounted to the wheel with a couple of bolts.  After both sides were done I put the wheel back on the bike and did a test ride.  I would say it's 75/80% better.  I still have some shuddering but definitely not as bad as before.  I don't feel pulsing in the lever so I don't think it's a warp (these are EBC rotors BTW).  I'm not all together sure that the pads didn't get out of whack either so today I'm going to scuff them a bit and see what happens.

[B.D.F.]

Just a guess but perhaps leaving a more even pattern (not a random pattern from doing it by hand) would remove all the shake. Scuffing the rotors without rotating them will leave an uneven pattern that has grooves in different directions. I use the wheel balancer so all of the scratches are in the same direction all the way around the rotor, and you really cannot do that by hand without some type of disc rotation.

You could probably do it on the bike just by elevating the front wheel while the bike is on the centerstand but that might leave abrasive behind, especially in the faces of the brake pads.

Nothing wrong with scuffing the pads but the pads cannot cause pulsing; they are the same all the way around the rotor. In other words, they cannot create more friction in one place than another without some defect in the rotor(s) itself.

Brian

This is one way....

http://zggtr.org/index.php?topic=566.0

I used a rotor hone in a drill and used  low rpms to scuff them up.  I took my wheel off and put it in a jig so that they were horizontal.  Brian is a vertical kind of guy, though, and likes to see things spin.  After I did the outsides, I removed the rotors from the wheel and did the inside surface.  I just remounted to the wheel with a couple of bolts.  After both sides were done I put the wheel back on the bike and did a test ride.  I would say it's 75/80% better.  I still have some shuddering but definitely not as bad as before.  I don't feel pulsing in the lever so I don't think it's a warp (these are EBC rotors BTW).  I'm not all together sure that the pads didn't get out of whack either so today I'm going to scuff them a bit and see what happens.

[VirginiaJim]

Well, there's something screwy going on then.   At low speed the bike stops normally...no shudder.  Stopping from higher speeds, longer time on the front brake, I hear/feel all sorts of pad noise like its slapping them around.  I did notice the last time I inspected them the pins were grooved.  Don't know if that's causing anything either.  Maybe the pads got shot during the first overheating (self induced) session and caused them to go bonkers....  Don't know, but something ain't right.

[B.D.F.]

It might be a warped rotor(s) then Jim- at low speed the hydraulic fluid (brake fluid) can move from one side of the caliper to the other to compensate for the warped rotor. At high speed, the fluid cannot move fast enough and that could be the cause of the shudder.

If they were my discs, I would try cleaning them again, if at all possible in some type of rotating fixture such as the balancing stand. It is fairly easy to do this and costs nothing but a little time so I would give it a shot. The next thing to do is to check the runout at the edge of the rotors.

Brakes really are pretty simple devices and there are not all that many different things that can go wrong with them. Sounds like your problem is going to be uneven deposits on the rotor or a warped rotor; something like air in the lines can't possibly cause any type of rotational pulsing.

Brian

Well, there's something screwy going on then.   At low speed the bike stops normally...no shudder.  Stopping from higher speeds, longer time on the front brake, I hear/feel all sorts of pad noise like its slapping them around.  I did notice the last time I inspected them the pins were grooved.  Don't know if that's causing anything either.  Maybe the pads got shot during the first overheating (self induced) session and caused them to go bonkers....  Don't know, but something ain't right.

[VirginiaJim]

I really don't want them to be warped as they're EBCs.  And if they do it as well, I think I'm going to cry a bit.

[Tactical_Mik]

I must say that cleaning then honing my rotors seemed to work at first.  With a few miles the front end shake is back when slowing from higher speeds.  Time to check the TIR again.    

[DaveO]

I am getting mine replaced through my local dealer since Kawi approved the warranty work.  I have never had more than just a hint of pulsing but it will be nice to know that the rotors are brand new and have fresh EBC pads.

if you were to  stay  with oem pads you probably wont warp them again.

[Jeremy Mitchell]

if you were to  stay  with oem pads you probably wont warp them again.

It had OEM pads on it. I have put about 2000 miles on my bike since getting my new rotors and EBC pads and haven't had any problems................yet.  [Knocks on wood]

[B.D.F.]

Yeah, I hear that Jim. Still, even if they are EBC and the warranty is up (or there never was one for warpage), it is always worth giving them a call and explaining your disappointment. They may replace them outright or give you a substantial discount on a new set.

But I would still lean toward the cleaning aspect. I have been surprised by it myself and had my rotors pulse after what I thought was more than sufficiently aggressive cleaning only to clean them again more aggressively and have them behave like glass.

Brian

I really don't want them to be warped as they're EBCs.  And if they do it as well, I think I'm going to cry a bit.

[VirginiaJim]

Yeah, I hear that Jim. Still, even if they are EBC and the warranty is up (or there never was one for warpage), it is always worth giving them a call and explaining your disappointment. They may replace them outright or give you a substantial discount on a new set.

But I would still lean toward the cleaning aspect. I have been surprised by it myself and had my rotors pulse after what I thought was more than sufficiently aggressive cleaning only to clean them again more aggressively and have them behave like glass.

Brian

Better glass than a pain in the a**, which is what they are now.

[Pokey]

Mine started pulsing very badly after I had to brake "very hard" on a down hill stretch......I blew by 3 very slow cages and 1 typical slow Hardly Ableson. I was on the boil and had a pretty good curve coming up, the pulsing lasted for a good while then just seemed to dissapear as quick as it happened. I am going to get some Galfer pads, and I will also keep an eye on my rotors to see if this occurs again.

[VirginiaJim]

Mine started pulsing very badly after I had to brake "very hard" on a down hill stretch......I blew by 3 very slow cages and 1 typical slow Hardly Ableson. I was on the boil and had a pretty good curve coming up, the pulsing lasted for a good while then just seemed to dissapear as quick as it happened. I am going to get some Galfer pads, and I will also keep an eye on my rotors to see if this occurs again.

So now you show up....hope your ride through VA was uneventful...  Like the avatar.  You don't have ABS do you?

[jsd]

I just warped up my second set of front rotors, 7400 miles. The dealer just called to say that Kawasaki is replacing the rotors with the new and improved 2011 rotors. There must be a difference that I am not aware of. I asked about the 2010 rotors and pads when my first set warped last year and was told that there was no difference in the rotors for those years. I am just happy to get them fixed without any argument, hopefully this will be the last time.

[B.D.F.]

The 2011 rotors have a much heavier carrier that the rotor is mounted to. The rotor <appears> to be the same as earlier models but the carrier has been beefed up by not removing so much metal from the carrier in the first place. Put another way, the new carriers have far fewer lightening holes in them on the 2011 models.

The pad material was changed in 2010 and carries a new part number. The original '08 and '09 pads are still available under their original part number. I am using the later pads on an '08 right now and they have significantly less original bite than the original '08 pads. They work fine, just less sensitive than the originals.

Brian

I just warped up my second set of front rotors, 7400 miles. The dealer just called to say that Kawasaki is replacing the rotors with the new and improved 2011 rotors. There must be a difference that I am not aware of. I asked about the 2010 rotors and pads when my first set warped last year and was told that there was no difference in the rotors for those years. I am just happy to get them fixed without any argument, hopefully this will be the last time.

[Bigcat]

I purchased my 09 used with only 900 mi on the clock. I noticed pulsing from the beginning. The severity would vary depending on temp, pace etc. With others here as well as a couple of local owners having continued problems, including replacement oem's, I decided to go with Galfers rotors and pads front and rear. Huge improvement in both feel and power. Not cheap but worth not having what may be a continual problem.   

[Rawman]

BDF, how many miles do have on the updated pads?  I have an '09 that I put '11 pads on.  I agree that at first they seemed to have less bite, but now that I have several thousand miles on them, they feel normal (or did I just get used to them?)

BTW: 22,000+ miles on the original rotors and just changed out pads roughly 2 thousand miles ago.