A friend pointed this out after riding my bike. I hadn't noticed before he mentioned it. It's pretty subtle, but I did notice it today on a ride around town. It almost feels as if the caliper is rapidly gripping then releasing the disk. Almost pulsating. I can especially feel it when coming to a complete stop. Any ideas? Are my rotors warped?
Thats what it sounds like.. were the rotor bolts torqued down all equally thru 2 stages and in a star pattern?
EDIT: Heh.. nevermind my post... Previous bike being an old Honda Hawk, I forget that new rotors have floating discs.. [bang]
This article is worth reading:
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml (http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml)
Clean the discs with brake cleaner and a Scotchbright pad. Also make sure the buttons that hold the rotor blade to the carrier are free. Remove the brake pads and sand them. While you are at it, chamfer the leading edge. Pray to the motorcycle gods. Now go out on the road and bed them in.
Have you replaced the pads recently? Could be something as simple as glazed pads. As said earlier give the pads a sand.
My guess would be warped or hot spots. As stated though, clean everything - don't forget the cups that activate the pads thenselves. Clean with q-tip and brake fluid.
Thanks for the information. I'll check it out. [thumbsup]
I had the exact same problem. Before you go over the edge just simply clean the rotors with a green scotchbright & dish soap. It's amazing how much junk comes off of a "clean" looking rotor. One cleaning totally solved the problem for me. Now I do it everytime I wash the bike.
Thanks for the info. I only just today got around to looking at my bike. I don't know what glazed pads look like, and maybe you guys can tell from my crappy photos, but the pads could use some replacement anyway (wear grooves no more!) I ordered up a EBC HH Front brake pad set from CA Cycleworks, and will give the rotors and calipers a good cleaning. My bike was a demo when I bought it, so I doubt the brakes were ever properly bedded in, although they were, and still are really stout.
(http://farm3.static.flickr.com/2465/3876340334_deaed0323c.jpg)
(http://farm3.static.flickr.com/2563/3876339268_58eb653ffe.jpg)
(https://farm4.static.flickr.com/3453/3876337136_2d1386dd48.jpg)
Hey - send those to me, I'd get another 10,000 miles from them!!!
To clean surfaces, I touch the pads on a belt sander and hit the rotors with a ball rotor on a drill. I've also used a 2" angle sander with a scotch type pad. I don't think you'll knock down much by hand, those things are pretty tough. If you do any of the above, you'll need to rebed the pads.
Looks like your throwin' away new pads.
Quote from: howie on August 18, 2009, 10:57:45 PM
Remove the brake pads and sand them. While you are at it, chamfer the leading edge. Pray to the motorcycle gods. Now go out on the road and bed them in.
Quote from: Norm on August 31, 2009, 03:36:42 PM
Hey - send those to me, I'd get another 10,000 miles from them!!!
To clean surfaces, I touch the pads on a belt sander and hit the rotors with a ball rotor on a drill. I've also used a 2" angle sander with a scotch type pad. I don't think you'll knock down much by hand, those things are pretty tough. If you do any of the above, you'll need to rebed the pads.
I use a
cheap-ass hand held orbital sander (http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=40070) with a fine grit paper. Usually takes about 2-5 seconds to get a new surface.
I do it in the driveway. Press HARD with the sander and turn it on. You just need to make sure the pad doesn't move around. Smooth concrete will hold the pad nicely.
Use the same pad and chamfer the leading edge as Howie suggested, but then do the whole pad again so there is no lip. You want a tiny chamfer.
Make sure to install them with the chamfer facing against the rotation.
??? So, at what point should I replace the pads? These have about 4mm of material left. The manual says to replace when the wear grooves are gone, but frankly, I don't remember there being any grooves...
Quote from: REDUC on September 01, 2009, 07:05:01 AM
??? So, at what point should I replace the pads? These have about 4mm of material left. The manual says to replace when the wear grooves are gone, but frankly, I don't remember there being any grooves...
4mm is a lot of material. i would not replace them. put the new ones aside and ride for another 8-10k miles on them.
Thanks, I'll do that.
Okay, now what do I do? I sanded my pads, scrubbed my disks with brake cleaner and scotch-brite pads, and put it back together. Took it out for a ride to bed in the clean surfaces. Let me elaborate: I accelerated to around 60 or so and braked progressively harder with each go to about 5-10. Did not come to a complete stop. Repeat 10 or 15 times, and came home. Threw the bike back up on the stands and noticed my disks now have a lot of pad material transferred onto them. And when I spin my wheel, it feels like the calipers haven't fully released their hold of the disks. Pads appear to be shiny, enough to pick up the reflection of my red from my frame. Any thoughts??
(http://farm3.static.flickr.com/2554/3881973554_ab7a2ffe41.jpg)
(https://farm4.static.flickr.com/3516/3881975442_32d9040304.jpg)
Do you still have the vibration?
No. So I guess that's one thing down. Should I be concerned that there is a significant amount of drag in my brakes, that I don't believe was there before? I mean I have to spin the wheel fairly hard by hand to get more than a full rotation out of it. That just doesn't seem right. Where did I mess up? Am I overlooking something obvious?
Maybe the pistons stick instead of moving freely, because of the washing?
I don't know what I'm talking about, but there should be some way of "lubricating" them (brake fluid?)
I think I'll try taking them apart again and cleaning some more. Hopefully it's as simple as some gunk in there. I have to admit that I'm a little let down that "Stopintime" doesn't know what he's talking about with regards to brakes... [coffee] Thanks, though. I'll give it a try.
Quote from: REDUC on September 02, 2009, 04:24:00 PM
No. So I guess that's one thing down. Should I be concerned that there is a significant amount of drag in my brakes, that I don't believe was there before? I mean I have to spin the wheel fairly hard by hand to get more than a full rotation out of it. That just doesn't seem right. Where did I mess up? Am I overlooking something obvious?
If you want to mess with it pull the dust boots off the calipers and clean everything up and reinstall.
Personally, I doubt the drag is bothering anything.
Okay, it just seemed excessive to me. As in unnecessary friction that the engine really shouldn't have to overcome to push the bike down the road. Also I'm concerned that the large amount of heat generated by said friction might cause some other issues, like brake fade, or even lock up? I don't know. I always thought that when you apply the brakes they should grip, and when you release they should FULLY release.
Quote from: REDUC on September 02, 2009, 05:15:15 PM
Okay, it just seemed excessive to me. As in unnecessary friction that the engine really shouldn't have to overcome to push the bike down the road. Also I'm concerned that the large amount of heat generated by said friction might cause some other issues, like brake fade, or even lock up? I don't know. I always thought that when you apply the brakes they should grip, and when you release they should FULLY release.
I don't disagree, but there are lots of things that can cause the drag...
and FULLY might be subject to interpretation. :P
If it's really as hard to spin the wheel as you describe it would be worth investigating.
I'd tap the calipers with a soft mallet, not rubber, to see if the shock loosens the pads.
If it works and the drag reappears I definitely would clean up the pistons...
but i wouldn't start ripping things apart just yet.
That's just me.
Do the pistons come out as easily as the pads? They seem to be just hollow cylinders. I don't want to start tearing into things either. I just want to solve what I percieve to be an issue. I want my brakes back!!
Quote from: REDUC on September 02, 2009, 06:13:00 PM
Do the pistons come out as easily as the pads? They seem to be just hollow cylinders. I don't want to start tearing into things either. I just want to solve what I percieve to be an issue. I want my brakes back!!
In order to remove the pistons easily you have to separate the caliper halves. That would necessitate o/haul kits which aren't available from Ducati. You might find them at Yoyodyne. I wouldn't disassemble without replacing seals/o-rings.
You
can remove the pads, push the pistons all the way back into the bore, remove the dust boots, and clean any dust or dirt that has accumulated from the bore.
My thinking is that bedding pads shouldn't cause the drag you're describing.
Okay, thanks for the insight.
Before taking the calipers apart make sure the drag is excessive. Some drag is normal, particularly when the bike is on a stand. Can you compare yours to another similar bike?
That's just it, my other bike has some drag, but not as much. And my dirtbike has none. Anyway, it's all back together now. I decided to just ride it and see. Hopefully everything goes okay and I don't eat shit and die. :-[