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Strange mark on disc
Posted: Thu Jul 05, 2007 3:44 pm
by Gemini
hi guys, recently noticed on my front left disc that a slight part on the outer section of the disc is rusty which makes me think not all of the pad is touchin the disc.
the bike stops fine, not pulsing in the lever. would i be right in thinkin that one of the pistons is sticking slightly?
gem
Re: Strange mark on disc
Posted: Thu Jul 05, 2007 4:08 pm
by masterofinsanity
is that another job on my list?

Re: Strange mark on disc
Posted: Thu Jul 05, 2007 4:12 pm
by Gemini
if u dont mind. fancy comin over to mine on weekend and doing it all?
gem
Re: Strange mark on disc
Posted: Thu Jul 05, 2007 4:15 pm
by rene
how do you mean a slight mark all the way round the disk? or just a dark mark were the pad was tutching?
Re: Strange mark on disc
Posted: Thu Jul 05, 2007 4:22 pm
by Gemini
on the outer side of the disc, there is rust all the way around as if the pad is only touchin the inner part of disc
gem
Re: Strange mark on disc
Posted: Thu Jul 05, 2007 4:25 pm
by masterofinsanity
i'll have a look the weekend mate.
Re: Strange mark on disc
Posted: Thu Jul 05, 2007 4:29 pm
by rene
your bike has 6 pots right? might be the bottom piston not tutching properly
Re: Strange mark on disc
Posted: Thu Jul 05, 2007 4:35 pm
by masterofinsanity
might be rust from not using the bike?
Re: Strange mark on disc
Posted: Thu Jul 05, 2007 5:25 pm
by Jamz
Aren't the pistons inline?
There should be a bit on the very outer edge of the disc that the pads won't touch.
Some bikes I've had, the disks rusted up instantly if it was stood in the rain, but always worked fine the second I rode it!

I think that was just the type of steel used?
It was probably my Aprilia AF125 that was the worst offender, but I think at least one of my VFR's did the same...
Re: Strange mark on disc
Posted: Thu Jul 05, 2007 6:42 pm
by Gemini
my mistake, the rust is on the inner half
and yeah 6 pots
gem
Re: Strange mark on disc
Posted: Fri Jul 06, 2007 3:25 pm
by RedexRobB
I had this on my rear disk Gem, i renewed the pads a while ago for the MOT and its now gone. No matter how much i used the rear brake before i put new pads on it still wouldnt clean up, but its fine now. I can only imagine the new pad has either worn into the shape of the disk (but the old one had loadsa meat left on it) or i loosened up the piston, who knows

Re: Strange mark on disc
Posted: Fri Jul 06, 2007 3:28 pm
by masterofinsanity
as robB would suggest, could be that the disc has worn unevenly and now you have changed the pads the new pads are completely flat so will only touch certain parts of the discs, they will wear in but you may need to get new discs depending how bad they are?
Re: Strange mark on disc
Posted: Fri Jul 06, 2007 3:31 pm
by RedexRobB
Yeah i was thinking on a new disk, i think they go for about 40 or 50 quid on ebay, not even that i dont think

but soon as it cleaned up it thought i might as well leave it. Might replace it when I give the 7R big a major service in September.
Re: Strange mark on disc
Posted: Fri Jul 06, 2007 9:51 pm
by Gemini
just ran my finger over disc and there is a slight ripple but nowt major, and also when i took old pads out they were worn odd.
so can i assume that as my new pads bed in they will fit the disc and this rust will disappear? i have only done 2miles round the block with new pads
gem
Re: Strange mark on disc
Posted: Fri Jul 06, 2007 9:57 pm
by gubbs
I'd deffo get a biopsy mate.
