Hi there. i have some quite heavy vibration through front brake, like the discs are warped on the ST4s. Its only done 15000 miles and had a relatively easy life - spends most of its time standing. I cant believe the discs have warped - especially top grade Brembo`s. Chap that had it before me (7 years ago now) did one trackday on it at Donnington but again I cant believe this would have warped the discs, neither of us are Rossi ! It`s done it for a while but i really don`t remember it being like it when i bought it ? I have tried new pads, cleaned discs with cleaner and brillo pad type stuff (nylon though not metal), brakes are bled up fine and i also cleaned the floating bobbins to make sure they`re all free to move etc. Interestingly the MOT tester said brakes are really strong and cant pick up any warping on his electronic rolling road brake tester. It`s only when you grab a handful at speed you notice it. What i can see is what looks like very minor pitting. its on both RH and LH discs inside and outside in the same place on the disc- as if pads have caused it (i.e. caused by laid up not being used) Photos attached - is this really enough to cause significant vibration - can it be remedied without buying brand new discs ?
The pitting I believe is absolutely nothing to worry about in terms of braking performance. I warped my discs , still have them on, I don’t feel anything braking from a higher speed but can very much feel the warp and pulsating on the lever braking in town . Might sound silly but are all the disc bolts done up?
not checked disc bolts to be fair - never undone them but will now check. fine at low speed high to medium speed braking only
Change your wheel bearings and report back. They are a lot cheaper than discs. Had this with a 916 biposto many years ago, also with the rear wheel bearings on a Gpz550. Neither of them could be felt when checking by hand with the wheel off the ground, but the biposto vibrated under hard braking, and the Gpz bearings deflected enough to make the sprocket retaining studs catch on the inside of the swingarm under hard acceleration. It took a bit more experience than I had at the time to find the mystery knock, but Dave Dawson, the local kawasaki guru took it for a thrash up and down on the local industrial estate and persuaded the failing bearing to collapse.
Had this on and off for a while, changed discs 4 times but turned out EBC had the wrong model number. Only way to check is with a run out guage. I have one like this https://www.google.co.uk/search?q=r...UQBA&biw=1920&bih=906#spd=2830540272092616703
I had that pitting before. Leaving wet pads in same place on disc then not riding for a while. On my 3rd pair. I now never leave parked more than a day following getting wet.
Probably really silly, but I presume you have checked your wheel balance, a weight may have come off and be causing this, for sure the cheapest thing to check, even before wheel bearings.
as @cookster says above, have you tried cleaning the bobbins ? sometimes these can seize and this can feel like a warped disc. you should be able to flex the inner and outer disc laterelly about 1 mm and rotate the bobbin (it will be firm but should turn) with your fingers, if not they are stuck
https://www.ducatiforum.co.uk/attachments/20200930_173412-jpg.220384/ @Rubbertoe £120 including postage these came off my rsv mille and were brand new
Hey Guys, I have seen the bobbin comment before. My understanding is that these are semi floating and should not move
Yes will check this but can’t get my head around why it wouldn’t vibrate the same when not under braking ?....will check all the same - like you say, cheapest in the process of elimination
Yes will check this but can’t get my head around why it wouldn’t vibrate the same when not under braking ?....will check all the same - like you say, cheapest in the process of elimination
