not long had an S4r on an 03 plate and its not been without a few issues but generally a good ride with a full history. Under higher speed (65+) heavy braking i have a front end judder. slower speeds and gentle braking its not there. had a few bikes and a few track bikes - so not completely inexperienced-- and am now at a bit of a loss ..bike only has 14k on it-- is it a characteristic in the bike? So to detail what i have done - front wheel off replaced bearings as they rattled ( not impressed as just went through mot) problem better but still there had front wheel re-balanced(slightly out) and run out done on discs - they are good sanded down pads to remove any deposits/glazing- pistons in calipers move freely enough problem still there had front end off inspected headbearings cleaned and regreased --- have taken to 2 dealers both agree nothing wrong with head bearings and no play in the fork bushes problem still there have tinkered with suspension settings - a more comfortable ride but problem still there. I'm not talking a major judder - just a judder that i know shouldnt be there -- so where the hell do i now look? front tyre is good (not squared off and running 30 psi up front and 33 rear) obviously not looking to spend where i dont have to but something isnt right so as i've done my money buying it - where should i be looking front tyre? pads? head bearings? fork service? or the rear ??-- but no play in swing arm or rear wheel and tyre just about scrubbed in
Sounds like a sticky bobbin to me, have you checked all the disc mounting bobbins are free to rotate? If one is stuck with dirt or corosion you may get the symptoms you describe
yep 2 threads ... got a tad excited and realised there was technical thread ... to use teenage speak --my bad !
HAPPY DAYS FOLKS .... purchase of second hand discs turned out good ... on and tested as of about 10 mins age ... no more front end judder ... all i gotta do is sort the front suspenders out and the bike may go where i want to go.. so as to what the issue was with original discs i know not... so may turn em into a couple of clocks.. unless someone on here wants to take a punt on them? and i promise not to start 2 threads bout same thing again ....
I have the same issue on my 1198. Judder as you brake, sometimes much worse than others and now have no real confidence with them. Checked run out of discs which is a little difficult with the floating discs but only a few thou. Thought it was sticking bobbins but the disc can easily be wobbled by hand. I also notice the judder when coming to a halt so I think it's a disc issue either a higher or lower friction section. Have thought about asking if someone has a spare pair I could try just to eliminate this line of thought before I spend on new discs???
I had the same with my SS....it was only slight, but it annoyed me....I changed pads, swapped discs over from one side to the other, tried different discs; constantly checked run out etc etc...... In the end I got so fed up with it, I took the wheel off, removed the discs and cleaned all the threads out with a tap, wire wooled the disc seats to clean them really clean, did the same to the discs, plus I ran a drill through all the disc holes to clean them right out..........I also cleaned out the caliper mounting threads and the mounting faces.........fitted new bolts. That f-in stopped it.
