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Discussion Starter #1
This is my first post. Thanks for having me. I was riding yesterday and let a turn sneak on me and got in my brakes really hard. From that point on, if I get in the front brakes, the front end gets super chattery. What did I possibly damage? Did I warp the rotors, overheat the pads? All oem system. What can I do to correct this, as I'm wanting to start doing some track days next year and want to atleast upgrade to track grade (not race grade as i will be a newbie on a track) Thanks for any help.
 

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I saw your other post asking about used rotors and calipers... there is no way you damaged anything using your brakes. Worse case scenario you deposited a heavier layer of pad residue on the rotors and now the “feel” is different. I would put the bike up on stands, and clean the rotors with some fine sand paper and then wipe them down with either brake cleaner or acetone to remove any deposits. If you want to be really thorough, you could also remove the calipers (don’t disconnect the brake lines!) and then remove the brake pads, and finally clean the calipers thoroughly with a mild dish detergent, distilled water, and a tooth brush; you should be doing that at least a couple times per year - more frequently if you start doing track days. I get out a bucket, hold the caliper over it, and use a spray bottle with the soap and water mix and spray it on the caliper. Then start scrubbing with the toothbrush and follow with another spray bottle with straight distilled water. All of this dirty liquid ending up in your bucket. I like to use some compressed air to help dry the calipers and then reassemble.

Finally, the way you retighten your caliper bolts is again, with the bike still on the stands, put the calipers on and only tighten the caliper bolts finger-tight. Spin the front wheel with one hand, and then grab the front brakes with the other hand and repeat a couple times. On the last “spin and grab” do not release the brake lever, then use your wrench to tighten the caliper bolts securely. Release the brake lever and use a torque wrench to set the caliper bolts to 34 N-m. All this was to properly align the brake pads with the rotors.


All of this will allow you to inspect and regain confidence that things are okay.
 

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Discussion Starter #4
Thanks alot Duc, I'll get on that tomorrow and see what happens. I'm just getting back into bikes. I've only put 500 miles on this one since I got it in June. I rode a Gixxer 600 from 2006 to 2011. I hope that's all it is.
 

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Discussion Starter #6
Duc, hopefully you'll see this in the next little bit. Ive got the wheel off cleaning everything up really good. Just had a question. When you were mentioning lining everything, you never mentioned at what point to tighten and torque the axle nut. Where would that come in the order of re-assembly? Thanks for all of your help so far as well!
 

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Duc, hopefully you'll see this in the next little bit. Ive got the wheel off cleaning everything up really good. Just had a question. When you were mentioning lining everything, you never mentioned at what point to tighten and torque the axle nut. Where would that come in the order of re-assembly? Thanks for all of your help so far as well!
Sorry. I didn’t expect you to be dealing with the axle. All the stuff I mentioned can be done without messing with the front wheel. If the axle needs to be torqued, because the front wheel was removed, that would be done before the brakes. And the axle, per the manual, needs to be tightened down in its own sequence.
 

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The axle has to be correctly torqued, then the front end “bounced”, and finally the two right-sided axle clamp bolts are torqued. Then the calipers are put back on the rotors, and the “special” alignment procedure performed.
 

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Discussion Starter #9
Yea I went ahead and pulled the wheel. I completely removed the rotors from the wheels and gave them a thorough cleaning. They are torqued back to 20 ft/lb per a torque value sheet I found for most bolts on the bike. I just got everything back together with everything still finger tight. So I will do the axle now, then the calipers. Thanks so much for your guidance. I will let you know in a bit if the chatter is gone.
 

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Discussion Starter #10
Well, unfortunately the chatter is still there upon initial braking during a hard brake. As I ease out on the lever approaching deeper into the turn, it goes away. Should I start with pads? Hard to tell what previous owner had on it to begin with.
 

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Get your tire up in the air and spin it. Inspect the rotors for waviness. How much pad to u have left on your brakes? Are your caliper bokta tightened down good?
 

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Discussion Starter #12
The rotors seem ok. I forgot to put fender back on when I tested it. So I could see the rotors turning as I was driving. Seemed straight. Pads have decent life in them. For all I know they were the cheapest pads previous owner could find.
 

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It’s a long shot, but I had trouble like you are describing - but during heavy braking at track days - apparently because when I installed my front axle I wasn’t torquing it to 127 N-m as specified in the manual; I had been been lazy and since my 1/2 inch heavy-duty torque wrench had broken I was using the 3/8” one that maxed out at 105 N-m. I spent years chasing that ghost! Thought it was pads/rotors/steering head bearings/ you name it. The last thing I did before it going away was buy a new torque wrench and give it the full 127.

Best of luck ... at least you now have clean and aligned brake calipers and rotors!
 

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The rotors seem ok. I forgot to put fender back on when I tested it. So I could see the rotors turning as I was driving. Seemed straight. Pads have decent life in them. For all I know they were the cheapest pads previous owner could find.
What you are describing sounds like a warped rotor. If the rotor is warped, it will push the brake pistons back into the caliper every time the rotor comes around while you are on the brakes. This will push fluid back up into your master cylinder and back to your caliper causing a pulsating feeling in your brake lever.
The service limit on rotor runout is 0.010" so even though it may have "seemed straight", it could very easily be well out of specification. I would suggest purchasing a dial indicator to check your rotors before you start throwing parts at it. They are fairly cheap online and can be used for all kinds of things. Also if this is not fixed soon, you may find yourself having caliper or master cylinder issues as well.
 

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Discussion Starter #16
Thanks for the help guys. I do have a dial indicator, just not a base to mount it horizontal. Looks like harbor freight has one I can use for like $12 so I'll check runout tomorrow after work.
 

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Discussion Starter #17
Stopped by HF and picked up the stand on my way home. Checked runout in the only clear spot on the rotor, just inside of where pad stops contact. There was a total needle movement of .006 on both rotors. That's an sd of like .003. Seems very negligible. Could this be a symptom of terrible or even just very old pads crystalizing do to over heating? That seems like the cheapest place to start. I'm looking to upgrade brakes before next season anyway for track riding, so I don't guess it will be terrible to throw on a few things I plan to upgrade anyway.
 

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Stopped by HF and picked up the stand on my way home. Checked runout in the only clear spot on the rotor, just inside of where pad stops contact. There was a total needle movement of .006 on both rotors. That's an sd of like .003.
That is within spec. Next thing I would check is the pistons in the caliper. One may be stuck causing the piston on the opposite side to push the rotor out of being true to the wheel. Also check the brake pad pins for grooves. And yes, buy new brake pads.
 

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Discussion Starter #20
That is within spec. Next thing I would check is the pistons in the caliper. One may be stuck causing the piston on the opposite side to push the rotor out of being true to the wheel. Also check the brake pad pins for grooves. And yes, buy new brake pads.
When I had everything apart cleaning calipers and rotors, I pushed all eight pistons back in smoothly, no grit feel whatsoever, back flush with the outer surface, with only my fingers. They seem to be functioning fine. I cleaned pins while they were out, and only groves were the groove for the spring in the very middle. I'm so stumped right now. Hoping maybe my pads are giving me some kind of a grip and slip effect and that will get me back smooth again.
 
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