I have started getting brake judder - not all the time but when its full on its quite bad. Seems to be worse when the discs are hot - manifested itself most badly towards the end of a 1000 mile tour in the twisties in Wales on quite a hot day and hadnt noticed it as bad before. I had found it slightly juddering when I picked it up and had decided was the wheel bearings, so I changed them. Didn't ride the bike in anger again until the above trip so clearly didn't sort it Have spun and cleaned the rotor buttons, headset is good, wheel bearings new and good, suspension also is good I am thinking about swapping out some discs - can anyone tell me - are the discs on a 748 interchangeable ie same runout? what aftermarket options can anyone recommend does anyone know the min thickness of rotors on an st3 - cant find any markings on the discs re this (weird I know) the discs have pitting in one particular area - quite bad - could this cause this do you think? has anyone else found a general solution - I see its a common problem after trawling the tinterweb Thanks
before you go changing rotors ...check the runout with a dial gauge....they're not as expensive as discs. From what I have learned its usually material build up on the discs and when mine started pulsing I carried on using them and it graduadualy faded away. I would pull the leaver till I just felt the pulsing without going to full pressure...knocked the high spots off.
before you go suspecting warped brakes, try cleaning your calipers! They tend to collect muck around the pistons and this gums them up and stops them from sliding properly, which can cause brake judder. Whip the pads out, take the calipers off, give them a good clean with brake cleaner and a toothbrush, clean the back of the pads and smear a little bit of coppaslip on the back to refresh them and try again. My Hyper does it all the time and it once failed the MOT because of it. The tester was convinced that the disks were warped as he could see the judder on his brake guage. I took it away, cleaned them up and took it back within an hour and he was very surprised that they were "perfect" after!
