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Feb 06

Posts: 3

luciano says:


I have a zx6r J2 track bike and on a slow speed when I use the brakes it feels as if there only working intermittently and on a high speed the front shudders a lot. Brake pads are new, brake fluid is fine with no air and they Galfer discs have done around 4000 miles in the last 4 years. Do you think the discs cause this problem? I was thinking about the front fork bearings.

Thanks very much


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  • Posted 3 years ago (06 June 2012 22:08)

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Jan 11

Posts: 267

cairnsie13 says:

Discs could

be warped. That would cause all the problems listed above but 4k miles on a set of discs is nothing. Then again play on the front wheel bearing could damage the discs. Or if the wheel has been removed and the wheel has been lying on the discs etc.

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Nov 07

Posts: 2457

smidget says:


As you have fitted new pads it sounds as if the calipers are in need of a service, replace seals and pistons, this will allow the pistons to move freely.

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Sep 06

Posts: 8579

fuzzrr says:


What Smidget said.....

It's going to be one of two thing. A) the discs or B) the caliper pistons are sticking.

I had the same problem on my R1. I did the usual swap the pads and discs etc etc etc to learn that the caliper piston had pitted and was sticking on the seal.

Take the pads out and pump the pistons out and inspect and clean. You may get away with getting the crud off them with brake cleaner. But if there is any damage to them then you will have to replace.

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Feb 06

Posts: 3

luciano says:


Thanks for your comments. I rebuiled the calipers last winter with new dust seals. All the pistons move freely. I started with this problem a few years ago before I put the zx6r away for 2 years until I managed to change everything in to a track bike. The bike is now over 31000 miles and never change the forks bearings. I am thinking bearings or the discs.

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Aug 09

Posts: 2726

MarcusMarsh says:


You could be looking at a worn wheel bearing but I would suspect that this would be likely to supset the handling of the bike generally - not just under braking.  Worn fork bushes would be similar as in I would expect some form of other handling problems as well.  Warped discs would be number one suspect and, fortunately, is the easiest thing to check.  Check the run-out on the discs before investigating the other possible causes.       

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Jun 09

Posts: 1053

Amateurcynic says:


Sounds like the disc's are warped as cairnsie suggests, mileage isn't a factor, it's quite possible to warp them at any time really, quick way to check is get the front wheel off the floor, secure something like a steel rule/screwdriver/pencil etc to the fork leg whilst it lightly touches the disc, rotate the wheel slowly and see if the disc makes more solid contact/gaps the guage. Not an exact system but could give you an indication either way

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May 12

Posts: 6

reecergv says:

galfer discs

I had Galfer discs fitted to my GSXR750. If the discs are fitted with the waves in line then the pads will pulse together causing a shudder through the lever as if the discs are warped. Some people actually like this with Galfer discs. Or if you remove one disc and rotate so the waves are offset then the pulse from each disc should compensate for the other. Let me know how you get on.

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