Floating disc excessive free play?

[husaberg]

Way back when I worked on cars, VH Valiants were prone to warping their ventilated front rotors, resulting in a pulsing pedal. The fix was to have them skimmed and they would never be a problem again. Never replaced any on vehicles of that era. Maybe the iron is softer now.

The ritual for the cast iron rotors in the early 80'sGp bikes was to use them then by hand spend hours rubbing down the high spots that appeared before using them in anger something to do with the grade of cast iron that they used?

i wonder if it was for the same reason.
Modern brakes don't tend to fade like the old ones maybe its just the pads being sintered metal and ceramic rather than asbestos and organic.

[Owl]

This doesn't seem right.

It's not. Had exactly the same condition to one of the front OEM Sunstar rotors on my 05 Speed Triple. Flogged out the carrier, however the other rotor was perfect? Still have those rotors somewhere floating about.

I figured at the time there may have been a bad batch of alloy to make the carriers?

[Blackbird]

Modern brakes don't tend to fade like the old ones maybe its just the pads being sintered metal and ceramic rather than asbestos and organic.

That's true but some modern rotors warp! The front rotors on my Duke 790 did that. The problem surfaced quite quickly from new. They were ok at open road speeds but extremely snatchy at low speeds. I took some readings with a magnetic base DTI, photographed the markings on the discs and then visited Boyds in Hamilton where I bought it from. They supported a warranty claim and new ones were supplied by KTM. Now better than they've ever been. Fitting EBC HH pads made a big difference too.