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Just dumping this here - in case it offers any help at all...

Truly warping a rotor is so rare, IME, both on bikes and cars. In both cases, pulsing/juddering on the brakes is most often overheated pad deposits embedded into the surface of the rotor, which can typically be removed with more aggressive pads.

On bikes, the next most likely scenario (but still only a small percentage of cases) I have seen is that the floating bobbins get caked up with brake dust and road grime and what have you, and one or two of them stick. Cleaning out the bobbins, while a chore, can help the rotor float again, and prevent pulsing.
 

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2021 SuperSport 950S
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Discussion Starter · #22 ·
When I bought my 05 Boxer Cup the rotors were warped. I replaced them with Galfer wave rotors w/ Galfer HH pads. The only problem is you get the wave rotor feeling (Small Pulsing) as the rotors can't be offset on this bike. I won't be buying wave rotors again unless I know they can mount with the offset.
Wheel Tire Sky Vehicle Automotive tire
 

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One rotor on my Triumph warped pretty quickly. Easiest way to check if it's warped or deposits is a run-out gauge. They're not terribly expensive and useful for anything round you want to measure. The guage can also be used for other things. Bought OEM rotors from a crashed bike, checked them and replaced the one bad one. No issues for the 7k miles before I sold it. Amazon.com : runout gauge
Depending on the issue. Sometimes pulsating is not caused by warped rotors. It could be just uneven deposit of the pad material.
 

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My 2017 had significant pulsing at low speeds when I bought it with 9k miles. I suspect that they were hot-spotted. I tried scrubbing them with scotchbrite, but it made no difference. Finally bought EBC rotors and HH pads and couldn't be happier with them.
 

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Also, if you grab hold of the disk, and gently but firmly rotate it, you should feel it move very slightly. Just a tiny bit if the disk is floating properly and bobbins not stuck. On the other hand, if they are stuck, it might be too late and has already caused warpage.
 

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2021 SuperSport 950S
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Discussion Starter · #27 ·
My symptoms are indicating warped rotors but I've started out by doing the deglazing, pads and rotors. I green scotchbrite and used brake clean on the rotors, scuffed the pads flat on 120 sandpaper. Result was not much better if at all. Hard braking it's more than a vibration/pulsing, the front of the bike shakes pretty good. It's not the abs kicking in.
My next step is to use a dial indicator on the front rotors to check for true and also check for frozen bobbins. Everything is so clean on this bike I really don't see a bobbin being a problem.
I like the Brembo rotors over the EBC rotors just because the amount of bobbins used, they just look engineered better. However the Brembo's sure do cost, about three time more and if you guys say the EBC are working I'll probably go with them if needing rotors.
Thanks for all the suggestions and I'll keep posting my progress in solving this problem. I have all of August before I plan to use the bike on the track.
 

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Lazy Eye:
I'm looking at the EBC rotors for replacement. Sounds like you really like them and recommend them. Did you get the regular round profile or the Contoured type? I think X For standard round and XC for contoured. Who did you get your from and do you have a part number for the ones you bought?
I've looked at the EBC website and it looks like they have the wrong part number from what I can sort out. Thanks
I bought them from Motosport.
MFG part number: MD841XC

I run them with the matching EBC HH pads.
 

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2021 SuperSport 950S
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Discussion Starter · #29 ·
Thanks LazyEye, those are actually the same Part Numbers I finally came up with too. Reassuring as it's always a PITA to return wrong parts.
Just an update on my fix. I went by the dealer yesterday and told them about the front brakes being a problem. They want the bike back to their service department and said they needed to repair/fix the problem. I'll be taking it to them next Wednesday and dropping it off. A&S Ducati, Roseville CA.
 

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Discussion Starter · #31 ·
Headed to the dealer with it today. Before we loaded it we checked the run out and they are .006 out.
 
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Depending on the issue. Sometimes pulsating is not caused by warped rotors. It could be just uneven deposit of the pad material.
I did everything. Took sandpaper to the rotors, cleaned out the bobbins (they were already clean), loosened and retorqued the calipers as should be done for floating calipers. Replaced the one rotor, which had the worst run-out measurement, problem fixed. /Shrug

From then, until I sold it (6-7k more miles and a track day), the original disc that I didn't replace never suffered any issues.

@Swamper As for .006" run-out, that should be fine. It was measured from lowest point to highest point in a full rotation? I checked the Triumph Street Triple manual I have and the service limit for runout is ".3mm", which is ".0118in". Both discs are equal? Either way, if the dealer is going to warranty cover it, nice!
 

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Discussion Starter · #33 ·
Checking with Brake rotor manufactures they state:
"The maximum allowable runout at the rotor friction surface is 0.002 inch (0.050 mm) as stated by most manufacturers".
 
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Discussion Starter · #34 ·
Up-Date:
It's been at the dealership for two weeks. They have been in contact with Ducati which advised them to deglaze the rotors which they did. They are still pulsing according to the service manager. He is telling me that it's a Ducati thing and they all do it to a degree as it's coming from the ABS electronics. He says I can come down to the dealership and ride another 950S they have in stock for comparison. I declined at this time to ride the other 950S they have so he said he was going to have his technician go ride it for a comparison to mine.
Do any of you feel a fairly strong pulsation even during lite braking. We have ridden a Ducati Streetfighter with the same brake system and it didn't pulse at all, in fact it had very good and smooth brake.
 

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No you are being bullshitted.

How would the ABS cause pulsing unless it's being triggered inappropriately?

Take the bike to another shop and get them to measure the runout on the disc.

The disc may be seized on its bobbins.

I bet your shop hasn't even checked it.
 

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Discussion Starter · #37 ·
The shop has checked the run-out and agreed it is out of spec. They advised Ducati whom replied with they needed deglazing. The shop is who I bought it from so five weeks ago. Ducati won't go any further under the warrantee which the shop/dealership is trying to use.
I already checked the Bobbins and all were clean with free movement.
I did check the run out before taking it to the shop. One was .005 and the other was .007 if I recall. The response from Ducati is you can't really measure rotors with bobbins accurately.
 

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Discussion Starter · #38 ·
Follow up date:
Just got off the phone with the service manager. His Technician took the other 950S they have out for a ride for the comparison. Technician reported the pulsing wasn't noticeable on it. Long story short he has authorized me to buy new Galfer Rotors and they will pay for them. I'll be able to pick-up my bike Tuesday. I get to install them myself which makes my very happy, I like doing my own work on the bikes.
Can anyone confirm the Galfer rotor number, I'm pretty sure it's DF807CW
 

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Hard to believe that Ducati would refuse to supply a part that costs them maybe ten bucks... I thought there was a miscommunication between the dealer and Ducati, but WOW the dealer is going to eat the cost of aftermarket rotors?! Good job on them!
 

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Discussion Starter · #40 ·
Yes after a little prodding the dealer did good. I never thought Ducati would view this as warrantee. In their view it would be a wear item I suppose. My dealer tried to put it on Ducati but really it was on them for selling a used bike and not picking up this problem in their initial used bike check over/preparation before they sold it.
I guess my only complaint would be when they tried to pull the old line, "They all do it to a degree"
When I told my son that's what they were saying yesterday after Deglazing them his comment was the same as Speedy23's.
I'll post the results/review of the Galfer Rotors when we get them on the bike. Probably do it at the same time we change the tires to the new Pirelli Diablo Rosso Corsa 2's I've ordered.
 
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