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Front brake pulsing...second time in 7500 miles

CC Rider

CC Rider
Member
My 2019 C14 now has 7500 miles on it. Took a trip to the smokies last spring, when I got home the front brakes were pulsing.

Both front rotors were bent. Kawasaki kindly replaced them under warranty. Afterward, the brakes were fine for over 2000 miles, mostly low speed close-to-home driving.

Just got back from a trip to Canada. By the time I got to Canada (1,000 miles of mostly highway driving) they began pulsing again. Day one of the return trip was 650 miles constant highway, high speed. The brakes pulsed severely after that.

It seems like the pads must be dragging. Any thoughts on how to correct this would be very much appreciated!
 
I would take a sanding block with medium grit and clean all sides of the rotors by sanding dry. Keep in mind you are not trying to remove disk metal, just cleaning them up. I used a sanding pad I found at the hardware store that was flexible with sandpaper on both sides. These were about !/2 inch thick. I don't see why Scotch bright wouldn't work too.

On my 09 the brakes would sometimes pulse after sitting at stop light with a slight slope. I would use the front brake to hold the bike since both feet were on the ground. I do understand your 19 has a different brake set up but it might be worth a try. What was happening is holding the bike with hot brakes would transfer pad material to the rotors which made them pulse. It feels just like a warped rotor when in fact it's not.

But I did think Kawasaki fixed the pad transfer by going to a softer rotor. Be sure to check the rear disk too.

Since I replaced the OEM used up pads with EBC pads, the issue has pretty much gone away.
 
Unless you verify that the rotors are warped or bent with a runout gauge, then chances are that is not the problem. I've found that on the C14 these symptoms are caused by a roughened area on the rotors. The cause is unclear but I believe it's due to some interaction between the pads and the rotors when the bike is parked.

I've had good results using a 3M paint remover disk in a drill to clean the rotors. You need to do all 4 surfaces so that means you need to remove the rotors from the wheel.
 
One thing (that may not be commonly known) that can warp a rotor is holding onto the brake lever after a high-energy stop. With the pad still in contact with the rotor while stationary, you get uneven heat transfer as most the rotor is not in contact with the pad...which can cause warping in the rotor when it is really hot. Personally I never hold on to the brake lever while stopped unless I have to.
 
Tim and jwh, thank you for the insights, which I will keep in mind. Hopefully that issue has been fixed, can't say I would be thrilled about cleaning rotors, which I have never needed to do on other bikes.

First set of rotors were checked with a runout gauge by the dealer, after which they were replaced. Also, the problem seemed to arise after an extended time on the highway - the first time I noticed pulsing was after about 90-minutes of constant driving. That may not be consistent with the pad transfer concept.
 
One thing (that may not be commonly known) that can warp a rotor is holding onto the brake lever after a high-energy stop. With the pad still in contact with the rotor while stationary, you get uneven heat transfer as most the rotor is not in contact with the pad...which can cause warping in the rotor when it is really hot. Personally I never hold on to the brake lever while stopped unless I have to.
Wow thank you. I have a new habit (not holding onto the brake).
 
I would take a sanding block with medium grit and clean all sides of the rotors by sanding dry. Keep in mind you are not trying to remove disk metal, just cleaning them up. I used a sanding pad I found at the hardware store that was flexible with sandpaper on both sides. These were about !/2 inch thick. I don't see why Scotch bright wouldn't work too.

On my 09 the brakes would sometimes pulse after sitting at stop light with a slight slope. I would use the front brake to hold the bike since both feet were on the ground. I do understand your 19 has a different brake set up but it might be worth a try. What was happening is holding the bike with hot brakes would transfer pad material to the rotors which made them pulse. It feels just like a warped rotor when in fact it's not.

But I did think Kawasaki fixed the pad transfer by going to a softer rotor. Be sure to check the rear disk too.

Since I replaced the OEM used up pads with EBC pads, the issue has pretty much gone away.
Different pads. Great idea.
 
Also a good periodic maintainence is to also clean the carrier buttons. Over time they get grimey and could keep the rotors from 'floating' freely. I clean mine at least once a year.

Norm
 
I went through the procedure with cleaning the carrier buttons and found no improvements when I had a warped disk carrier. So I have a confession to make. A couple of winters ago, I had the front tire replaced. I dropped it off at a power sports place who has mechanics I would not let near any motorcycle I own. But they do have a Snap-on motorcycle wheel balancer and have had good luck with that. short version: I dropped off a front wheel with a new tire replacement. Picked it up after they were done. I transport the front wheel in an old car tire to keep the rotor from the floor of my Bronco. As I was loading, there was ice and snow on the ground so my feet decided they wanted to be someplace other than under me. I lost my balance, resulting in a rotor hitting the side of the tire I was trying to put in the center of. I thought, that probably warped the carrier.

It did and was warped. I found this for sure when the wheel was mounted with calipers installed. The rotor did not hit the pads evenly on one side. I ordered used set of rotors off E bay. These rotors were off a newer C14. I discovered the newer rotor's appeared to be made of a softer metal. One could visibly see where the pads contacted the rotor. With my 09 rotors, this was not the case. But I went ahead and replaced the disk with the warped carrier. Some place during this evolution, the other side carrier got warped too. I don't recall being real rough with the wheel. So there was an element of surprise.

I did not have access to a dial indicator that would fit my needs. So rather than go through the mess of replacing the rotor, I got my rubber mallet out. I banged and tapped on that rotor until it did not hit the caliper pads with high or low spots. With the wheel off the ground spinning the wheel was easy. Somehow I got the rotor to run smooth and to this day I have not experienced any ill effects. Pull the brake lever and this thing stops.

At some point I'm going to put the OEM rotor back on and use the same shade tree and/or red neck way of precision straightening a warped carrier.

I don't quite understand the rotors feeling warped after extended riding. The only thing that comes to mind in that case is a dragging caliper. This bike has enough power one might not notice a dragging caliper. Next question, both rotors were found warped and replaced? Or was it just one?

One other thing I found when the front rotors pick up pad material. From a some what brisk pace I found hauling the bike down with a slow but increasing pressure on the brake lever. Then letting it go just before coming to a complete stop let the brake go also to seems to clear the rotors of pad material. If there is stuck pad material on the rotor, it feels and acts just like a warped rotor would when in fact it's straight.

This statement is NOT pointed at the OP because he stated a mechanic found the rotor/s warped with a dial indicator.
 
I went through the procedure with cleaning the carrier buttons and found no improvements when I had a warped disk carrier. So I have a confession to make. A couple of winters ago, I had the front tire replaced. I dropped it off at a power sports place who has mechanics I would not let near any motorcycle I own. But they do have a Snap-on motorcycle wheel balancer and have had good luck with that. short version: I dropped off a front wheel with a new tire replacement. Picked it up after they were done. I transport the front wheel in an old car tire to keep the rotor from the floor of my Bronco. As I was loading, there was ice and snow on the ground so my feet decided they wanted to be someplace other than under me. I lost my balance, resulting in a rotor hitting the side of the tire I was trying to put in the center of. I thought, that probably warped the carrier.

It did and was warped. I found this for sure when the wheel was mounted with calipers installed. The rotor did not hit the pads evenly on one side. I ordered used set of rotors off E bay. These rotors were off a newer C14. I discovered the newer rotor's appeared to be made of a softer metal. One could visibly see where the pads contacted the rotor. With my 09 rotors, this was not the case. But I went ahead and replaced the disk with the warped carrier. Some place during this evolution, the other side carrier got warped too. I don't recall being real rough with the wheel. So there was an element of surprise.

I did not have access to a dial indicator that would fit my needs. So rather than go through the mess of replacing the rotor, I got my rubber mallet out. I banged and tapped on that rotor until it did not hit the caliper pads with high or low spots. With the wheel off the ground spinning the wheel was easy. Somehow I got the rotor to run smooth and to this day I have not experienced any ill effects. Pull the brake lever and this thing stops.

At some point I'm going to put the OEM rotor back on and use the same shade tree and/or red neck way of precision straightening a warped carrier.

I don't quite understand the rotors feeling warped after extended riding. The only thing that comes to mind in that case is a dragging caliper. This bike has enough power one might not notice a dragging caliper. Next question, both rotors were found warped and replaced? Or was it just one?

One other thing I found when the front rotors pick up pad material. From a some what brisk pace I found hauling the bike down with a slow but increasing pressure on the brake lever. Then letting it go just before coming to a complete stop let the brake go also to seems to clear the rotors of pad material. If there is stuck pad material on the rotor, it feels and acts just like a warped rotor would when in fact it's straight.

This statement is NOT pointed at the OP because he stated a mechanic found the rotor/s warped with a dial indicator.
Tim, thanks for your comments. The red neck precision straightening is an interesting perspective, particularly since it seemed to work.

On my bike pulsing is only noticeable when brakes are applied at 60 mph or more, but at that speed the pulsing is significant. That was the case the first time they pulsed, and replacing both front rotors fixed it.

With the bike on the centerstand and front wheel in the air, the wheel spins freely with no hint of grab. There are no visually obvious deposits on the rotors. Perhaps the pads are the problem. As soon as it stops raining I will give slow but increasing pressure on the brake lever a try.

In any case, the bike is under warranty and should not be doing this. So the local Kawi dealer will have a chance to provide an opinion as well.
 
Only noticeable over 60…?

What happens if you use the rear brake pedal only? I believe that applies braking force at speed to the rear and (not 100% sure on this) front right side caliper.

Will be interested to hear what dealer has to say.
 
Tried Tim's squeeze the brake from high speed idea. Below 50mph, brakes are perfectly smooth. At speeds above 60mph, they pulse but it smooths out with increasing speed. Between 55 and 60mph, the front shakes violently. Brake hard from speed and the zone between 55 and 60 is clearly worst. This is using front brake lever only.

Rear brake has some pulse, very much reduced. Since the front wheel spins freely on the centerstand, I'm beginning to suspect the pads.
 
My 14 pulses as yours does. Noticeable at higher speeds, mostly pulling front brake. I have noticed also that it tends to be worse in traffic or canyon riding. If I ride the interstate for a long distance and get off, no (or not much) pulse. If I brake several times in a row, then it gets really bad, but oddly enough will go away after time. This makes me think the pad transfer thing is an issue, I would not expect a warped rotor to un-warp itself. But I have the new rotors supposedly.
 
Hauling down from a rather brisk speed and using the front brake with increasing lever pressure and then releasing right before it stops. Works for me. I have a non linked ABS brake system. Pull the front brake lever and I get the front brake only. Push on the rear brake pedal, I get the rear brake only. If you have the linked brakes, I'm not so sure there is enough braking force up front to completely clear any stuck brake pad material from the rotors.

BTW, not picking on anyone, but I have not ever come across a warped rotor un warping it's self. The only way I know of unwarping a rotor is to turn it at a brake shop. The rotors on the C14 might take a little bit of being turned but not much as far as I can tell.

I do know things settled down after changing to the EBC brake pads. A little noisy with light applications but the bike stops on a dime when needed.
 
If your problem is still ongoing, see if you can verify that fluid is coming out the small return hole in the master reservoir when the brake lever is pulled and released.

If it is blocked, or restricted, when it is ridden a long time the fluid in the lines could be heating up, expanding, and causing the brakes to drag enough to heat and warp the rotors.

If you bring it in for new rotors under warranty again, suggest a possible new master cylinder too.
 
If your problem is still ongoing, see if you can verify that fluid is coming out the small return hole in the master reservoir when the brake lever is pulled and released.

If it is blocked, or restricted, when it is ridden a long time the fluid in the lines could be heating up, expanding, and causing the brakes to drag enough to heat and warp the rotors.

If you bring it in for new rotors under warranty again, suggest a possible new master cylinder too.
Thanks, will do. Bike goes in Sept 4
 
I'd also take a look at all the caliper pistons, four on each caliper. After a few years a layer of brake dust will build up around the exposed outer diameter of the piston. The brake dust will form a dirt ring around the piston that will make it harder for the piston to retract when the lever is released. Pad stays in contact with rotor just a little harder than usual, or worse, and you know what happens after that. Take the caliper off the fork, remove the pads, GENTLY give the brake lever a slow squeeze to extend the pistons...a 1/4" should work, till you see a clean piston surface. With a length of emory cloth (about 1/2" wide by 10" long) around the piston you can remove the brake dust ring, stay away from the seal of course. Blow off the loose dust with a gentle shot of air, wear a mask and safety goggles of course. When it's all clean you should be able to push the pistons back in enough with the pads to put the calipers back on over the rotors. I also like to remove and clean up the pins that hold the pads in the calipers just to make sure the pads can't bind on those.
 
One thing (that may not be commonly known) that can warp a rotor is holding onto the brake lever after a high-energy stop. With the pad still in contact with the rotor while stationary, you get uneven heat transfer as most the rotor is not in contact with the pad...which can cause warping in the rotor when it is really hot. Personally I never hold on to the brake lever while stopped unless I have to.
Good to know. Thanks for sharing.
 
Also, be sure the master cylinder is not overfilled. This could cause the brakes to drag, especially when hot.
 
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