Warped rotors? - Yamaha R6 Forum: YZF-R6 Forums
 
LinkBack Thread Tools Display Modes
post #1 of 9 (permalink) Old 07-04-2019, 03:01 AM Thread Starter
Just made this great wheelie.. did you see it?!
 
Join Date: Apr 2019
Posts: 95
Warped rotors?

My front break is pulsating when breaking and the lower the speed the more noticeable it is and the harder I break the less noticeable it is. I feel it in the lever kinda like Im hitting small bumps and the the lower the speed the longer intervals between each bump. Only think is that the previous owner said he got new rotors not long before I bought it. Is there an easy way to see if they are in fact warped without a bike stand?
Ravager33 is offline  
Sponsored Links
Advertisement
 
post #2 of 9 (permalink) Old 07-04-2019, 03:40 AM
I eat my R6
 
Join Date: Jan 2016
Posts: 2,681
Bike: 2015 R1
Garage
Re: Warped rotors?

it's too hard to see without having the wheel spinning off the ground. it's best to stick the front wheel on a balancer and use a dial indicator to measure the run out. but it could just be pulsing because of a buildup of the brake pad materials. if the previous owner didn't sand off the old pad material and the bike is now using a different brand or compound of pad it causes problems like this. you can get a red scotchbrite pad or 120 grit sandpaper and scuff the rotor surface to remove the old pad materials. it doesn't take a lot of scrubbing to be effective. just scratch it up a little bit on both sides of each rotor. then take a piece of 120 grit sandpaper and lay it on a really good flat surface. rub the pads on it in a figure 8. this will remove any old pad residue from the pads you have.
if the pulsing you are feeling is from this scenario it should stop after you do this.
yamahacrazy is offline  
post #3 of 9 (permalink) Old 07-04-2019, 03:50 AM Thread Starter
Just made this great wheelie.. did you see it?!
 
Join Date: Apr 2019
Posts: 95
Re: Warped rotors?

Thanks. Im assuming I need to take the wheel off to do this?
Ravager33 is offline  
 
post #4 of 9 (permalink) Old 07-04-2019, 04:09 AM
I eat my R6
 
Flyers28's Avatar
 
Join Date: Jul 2014
Location: Philly
Posts: 1,889
Bike: 07 Candy Red R6
Re: Warped rotors?

Does your brake lever initially feel a little softer at first squeeze then tighten up after a quick release and squeeze? If a rotor is slightly out of round it will push a piston in slightly more on the high side. This causes that initial soft feel before the pad is completely seated on the rotor face under braking. My rotor is ever so slightly out of round and I suffer from the exact thing.

You can also hear it when you spin the tire by hand. You can hear the "pulsing" sound as the wheel spins. But like yamahacrazy said, it could just be material build up too. So start there for sure.

To clean the rotors no you don't really need to take the wheel off. But take the pads out and scrub those down as well. But taking the wheel off is simple. Follow the service manual. Before you tighten the pinch bolts make sure you take the bike off the front stand and without squeezing the brake lever push down on the triple clamp several times with some force to set the forks on the axle.

Follow a brake pad break-in procedure after doing this to set the pads to the rotor face again.
Flyers28 is offline  
post #5 of 9 (permalink) Old 07-04-2019, 04:23 AM
Why yes I don't!!!!!!!!!!
 
TurboBlew's Avatar
 
Join Date: Jun 2010
Location: FL
Posts: 4,721
Bike: 2007 In Heaven
Re: Warped rotors?

Quote:
Originally Posted by Ravager33 View Post
My front break is pulsating when breaking and the lower the speed the more noticeable it is and the harder I break the less noticeable it is. I feel it in the lever kinda like Im hitting small bumps and the the lower the speed the longer intervals between each bump. Only think is that the previous owner said he got new rotors not long before I bought it. Is there an easy way to see if they are in fact warped without a bike stand?
I would question "what type" of rotors the previous owner installed & why? The service life on stock ones are pretty long. Also you dont just slap a set of rotors on ala some shade tree folks do. The calipers should have been cleaned and reset. Real easy way to tell is the slide pins. Do they look new & polished? Is the fluid reservoir topped off above the "FULL" mark?
Amazes me how many "pro" mechanics working in service bays NEVER even bother to touch the calipers on street bikes.

FYI... think about how much debris/moisture your front brakes are getting exposed to with vehicles spewing water and dirt in front combined with heat.
TurboBlew is offline  
post #6 of 9 (permalink) Old 07-07-2019, 02:21 AM Thread Starter
Just made this great wheelie.. did you see it?!
 
Join Date: Apr 2019
Posts: 95
Re: Warped rotors?

Not sure of the brand of the break rotors but I would guess he replaced them cause the bike has been downed. I don't have a stand so its kinda hard to see if they are warped but I guess I can clean them and see if that does it. While I'm at it I might as well clean the calipers as well, what kinda stuff should I use to clean them? And what do I use to scrub the pads, 120 sandpaper too?
Ravager33 is offline  
post #7 of 9 (permalink) Old 07-07-2019, 03:18 AM
Why yes I don't!!!!!!!!!!
 
TurboBlew's Avatar
 
Join Date: Jun 2010
Location: FL
Posts: 4,721
Bike: 2007 In Heaven
Re: Warped rotors?

Quote:
Originally Posted by Ravager33 View Post
Not sure of the brand of the break rotors but I would guess he replaced them cause the bike has been downed. I don't have a stand so its kinda hard to see if they are warped but I guess I can clean them and see if that does it. While I'm at it I might as well clean the calipers as well, what kinda stuff should I use to clean them? And what do I use to scrub the pads, 120 sandpaper too?
see if someone local can loan you some? This is where filling in your location helps.
To view links or images in this forum your post count must be 5 or greater. You currently have 0 posts.


First Id be checking the wheel, off the ground, for free wheel revolutions.
Undo the calipers and check it again
Inspect the calipers.
Clean with mild degreaser like simple green. Any metal should be polished to look new.
When youre done take a q tip dipped in DOT4 and lube the seals.
120-180 grit should be good enough to renew the rotor & pad surface. When doing them by hand keep the rotor turning so youre not concentrating on 1 area. After you finish use brake cleaner on a clean lint free shop towel to hit the rotors a final time. Just clean the pads with mild degreaser.
After all that youll have fresh surfaces to mate. I wouldnt start out grabbing a handful of brake... build some heat between the surfaces with a low speed drag test ride... working up to a hard stop.
Lastly make sure your brake fluid level is slightly above "low"
TurboBlew is offline  
post #8 of 9 (permalink) Old 07-07-2019, 09:14 PM
I eat my R6
 
Join Date: Dec 2014
Location: Southwest Ohio
Posts: 1,260
Bike: 2008 Yamaha YZF-R6s Stock
Re: Warped rotors?

If the bike has been involved in any collisions, it could be the wheel. If the rotors were replaced and problem solved, only for it happen again, then there's something else going on. They don't warm without a reason; particularly the stock ones.
Intuit is offline  
post #9 of 9 (permalink) Old 07-08-2019, 12:51 AM Thread Starter
Just made this great wheelie.. did you see it?!
 
Join Date: Apr 2019
Posts: 95
Re: Warped rotors?

Well I don't really know why he replaced the rotors maybe he just liked this look better but I do know the bike has been down so it is a possibility. I'll start with cleaning the stuff but I'm not home for another few weeks..
Ravager33 is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Yamaha R6 Forum: YZF-R6 Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome