Have you a dial guage? As you don't really know the history of the discs I would say definitely going to be the discs, especially if they have come off a track bike, they might well look ok but if they have any runout it's going to cause an issue, Can you not bung your OE ones back in? Take it your Brembo callipers are new? What pads you running?
Are you 100% sure your not rubbing disc to calliper body, I know how tight they run with my T-drives and the Brembo GP callipers... you might just want to check the gap again!
I don't unfortunately. These are the discs: https://www.1000rr.co.uk/threads/brembo-oro-discs-320-mm.32190/ I sold my OE discs Brembo M4's are brand new and installed a few months ago... the pads are the standard ones that come with the M4's chap. I do have some Bendix MRR's to go in!
I'm 99% sure ... as would have noticed. Calipers have been off a few times but will double check tonight!
My money is still being a disc issue of some description, running out perhaps, you won't see it unless you have a dial gauge to check! But still baffled as to why it went away for 50 miles or so and now it's back the callipers are definitely centralised?
Possibly due to brake pads bedding in again? After disturbance? Won't a disc issue with variable DTV cause pulsing at lever? I don't get any pulsing at all. Calipers centralised? I.e. install loosely... lock the front brake lever on - then torque up? - Yes I have always done that ... but the company who did the head bearings might not have done.
Yeh I would definitely check to see if they centralised them correctly, I know it's a rare issue but it's been documented on other forums regarding bad pads so you could try the Bendix pads, like I said seems odd after it's been ok for a while and now it's back, perhaps something on discs has contaminated the pads, Are the discs showing any heat spots?
Bobbins just about rotate but very stiff ... can't see any heat spots on the discs no. Will post a picture.
So what's the verdict?? They look like discs in the picture and can't tell anything by seeing a picture, are they running out? Also if you haven't already checked the thickness with a micrometer.... think the ORO should be 4.5 but check just in case I'm wrong.....
Didn't get time last night... I'm stripping it down tonight as off work tomorrow. Plan is to Scotch-Brite the discs (trying to find some!) and clean up the buttons with brake cleaner. Once spotless install with new Bendix pads. Will also check head and wheel bearings and ensure all fully aligned when it goes back together. There are no locating pegs for the M4's so I've just been holding the brake lever on whilst torque up. However, they do have some up / down movement in relation to the forks (about 1-2mm) that I wonder has any effect? Thickness of discs is fine. I measured them quite recently and same thickness as new. i.e. 5mm. DTI wont be here till Friday ... so if that lot doesn't work DTI'ing the discs will be my next step and I REALLY hope it is not the discs... bloody expensive else. Plan tonight is strip front end down ... it might be my imagination but the front of the bike felt pretty vibey to me on the way to work. I.e. without touching the brakes.
I know pictures, especially flash ones can be deceiving, but your discs look like you’ve had some pretty aggressive pads at them. Don’t think it’s got much to do with the issue, just an observation. If you're looking for Scotchbrite and struggling ... It's on one side of the pan scrubs you get in the supermarket, the foam ones..... I just have to make it plain here,.. this is only an observation, I am a Bloke and don't get involved with Women’s tools and responsibilities.
The discs have only had Brembo pads used. Thanks - didn't think that would be aggressive enough hence was looking for red scotch brite?
Sounds like a plan then, don't worry about float in the forward and rear movement, it's the centralisation that's more important, once the pistons expand against the pads it needs to be square flat against the disc surface or you well end up with all sorts of issues, including brake binding and uneven contact surface causing uneven pad ware and oscillation issues!
