Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Pulsating front Discs.........

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by T2, Sep 20, 2005.

  1. My Sprint has just developed this problem since replacing the front disc pads.
    The discs are not warpped when dialled in for calibration.
    Any thoughts?

    PS Its a NISSIN system and the same or similiar is on a multitude of bikes.... :(

  2. the discs are not bolted on properly?
    the pads are not put in properly?
    did you do this yourself?
  3. The work was actually done by a Triumph dealer and all appears well......
    That's the puzzle.
  4. Best to take it straight back there and let them know, be vocal if you have to.
  5. Thanks Smee..........
    We' ve drawn the same conclusion.
  6. mine does the same thing! :shock: i had meant to ask about this but hadn't got around to it.

    it only happens under extremly heavy braking, only ever at low speed (i'm not in the habbit of grabbing the front brake at moderate/high speed so i don't know if it would do the same)

    its a little disconcerting but as i only hit the brakes hard every month or so i haven't had it looked into.
  7. Sometimes floating rotors get tight. The hard braking of course inputs heat and therefore causes them to move a little. I would be looking at the rotor mounts and making sure they move freely and the rotor is floating free. Another cause can be when pads are changed and they are a little different than the old pads in composition. This means they work at different tempatures and so differnent expansion and contraction rates. Only thoughts - so would take back to dealer. That is why you pay em the big bucks :D

  8. Tones.... I just checked them again and the discs DO appear to be tight. I actually loosened them by hand, just flexing them from side to side then back and forth in their mounts etc.
    I keep the bike looking like new, ie continually washing and cleaning it etc. Some water may have started some minor corrosion.
    I am going to get some brake cleaner today and givem a thorough clean up and working over tonight, without disassembly.
    Brake cleaner has NO residues so you can't do ANY harm with discs or pads etc.
  9. The point is you had your brakes worked on by a dealership and they didn't notice that the brakes were pulsing. Why didn't the tech doing the work pick it up???????
  10. Brake pads can 'dig' into the disc on the leading edge. Filling a taper along the leading edge of the pad stopped the problem.
  11. I have had this problem when I bought my bike, and could have sworn that the discs were warped, however it turned out that the problem was actually an air bubble in the brake lines after the braided lines had been removed and the stock lines retrofitted.

    Because your lines have not been off (well shouldn't have been for a pad change anyway!), you may think this information is irrelevant.

    However, there may have been some air in the line beforehand, and the dealer may have left the caliper hanging down while changing the pads (a no no!) allowing any air present in the line to travel up to the lever. Properly bleeding the system should remove the pulsating.

    Even if the discs are a floating system and appear to be rigid, the basic fact of the matter is that if they are not warped, then this cannot be contributing to the feeling you are receiving at the lever.

    IMO a proper bleeding of the system by the same dealer (if you still have confidence in them!) will alleviate the problem. :)