Yamaha R6 Forum: YZF-R6 Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
117 Posts
Discussion Starter #1
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 I´m 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?
 

·
Registered
Joined
·
2,872 Posts
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.
 

·
Registered
Joined
·
1,931 Posts
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.
 

·
Why yes I don't!!!!!!!!!!
Joined
·
4,809 Posts
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 I´m 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.
 

·
Registered
Joined
·
117 Posts
Discussion Starter #6
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?
 

·
Why yes I don't!!!!!!!!!!
Joined
·
4,809 Posts
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. :wink:

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"
 

·
Registered
Joined
·
1,558 Posts
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.
 

·
Registered
Joined
·
117 Posts
Discussion Starter #9
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..
 
1 - 9 of 9 Posts
Top