i have a sticky piston, i get a little chatter at low speed, if i clean the calipers make sure ALL the pistons move freely, the noise goes away.
also make sure your steering head bearings are correctly tensioned
I have NEVER cleaned discs......you think the ~300psi pushing on the rather abrasive pads won't do the job?
if you sand or scrub with anything abrasive leaving marks/scratches on the discs the disc will eat the pad faster until the marks are gone
Brembo is in the business of selling parts.....remember 4 piston/2 pad calipers? pad changes were cheap......then they went to 4 piston/4 pad calipers.....
what happened?..... the pad area got ~15-20% smaller and the price doubled didn't it?
and the pads wore faster
the discs too
remember full metallic race pads, back when they were made with asbestos?
in endurance racing....racing 3,000mi A DAY, pads lasted over a year......iron discs never wore out......and they were perfectly flat and shiny
my R1150GS eats pads and discs and they are all wavy
oh, thats right they're Brembos