Author Topic: Front Brake Pulsating  (Read 5382 times)

Offline Lucky Lou

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Front Brake Pulsating
« on: February 01, 2013, 03:34:24 PM »
I have been having odd vibrations coming from the front brake its a 93 K75 (twin disc) with ABS 40k miles.The ABS is not working and shows the red fault light and flashing warning, i pulled the relay but when i use the front brake i get a odd pulsing a bit like ABS operating. I rebuilt the brakes when i got the bike (it had been off the road for 10 years) i have some spare time coming up and plan to strip the front brakes again but wondered if it could be the the ABS system and should i disconnect it, Has anyone else had anything similar and any advice.
Lou
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Offline Inge K.

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Re: Front Brake Pulsating
« Reply #1 on: February 01, 2013, 04:33:33 PM »
I would first checked if the discs is straight, and if the mounting surface is clean (if they have been changed, or removed from the wheel some time back).

Inge K.
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Offline Lucky Lou

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Re: Front Brake Pulsating
« Reply #2 on: February 01, 2013, 04:50:44 PM »
I would first checked if the discs is straight, and if the mounting surface is clean (if they have been changed, or removed from the wheel some time back).

Inge K.
When i did the rebuild i did strip the discs off the hub, i marked them and put them back in the same location, i will strip them off again to check for alignment. thanks Inge
Lou
There are no wrong turns on a motorcycle

Offline Inge K.

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Re: Front Brake Pulsating
« Reply #3 on: February 01, 2013, 04:55:49 PM »
Did the brake pulsate before you removed the discs from the wheel?

Inge K.
  • Norway

Offline frankenduck

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Re: Front Brake Pulsating
« Reply #4 on: February 01, 2013, 05:07:50 PM »
If the bike sat for ten years in the same place then it may have left a spot in the rotors where the pads sat.

If your rotors have enough meat left then a couple of K owners have told me these guys did a great job refurbishing their rotors: http://www.truedisk.net/
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Offline Lucky Lou

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Re: Front Brake Pulsating
« Reply #5 on: February 01, 2013, 05:29:47 PM »
If the bike sat for ten years in the same place then it may have left a spot in the rotors where the pads sat.

If your rotors have enough meat left then a couple of K owners have told me these guys did a great job refurbishing their rotors: http://www.truedisk.net/
The rotors looked good but the bike was a none runner when i got it so i dont know if there was an earilier issue.
Lou
There are no wrong turns on a motorcycle

Offline K75RT Keith

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Re: Front Brake Pulsating
« Reply #6 on: February 02, 2013, 04:02:46 PM »
It is not uncommon for the rotors to warp.  To ell if the rotor is the problem you'll need to use one of 2 inspection methods. First would be removal of the rotors and mount them so they will rotate .  Yo will have to have them absolutely vertically from a perfectly flat surface like a machine shop inspection table made of stone.  A dial indicator will need to be set-up next to and touching the braking surface of the rotor and then rotate the rotor 360 degrees (like on the rim) checking for deflection.  You will need to check both sides of each rotor.   The other option is not quite a precise,but works.  After you have found a flat bit of pavement or a flat garage floor, put the bike on the center stand and block under the engine so the front wheel is off the ground.  Place a dial indicator to the rotor, zero it out and check for deflection on both front rotors.  If they are warped, you will find it.   Most likely the rotors cannot be turned down and maintain enough thickness to remain within service limits.   A set from a breaker may have the same issue.     
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