Rear brake rubbing on cb500

I replaced my rear brake disc and pads on my cb500 approx 700 miles ago, and put new fluid in at the same time. I have a slight rubbing/resonating noise that happens if i am slowing down with just a tiny bit of rear brake. The brake seems to work well and locks up fine, if i put a reasonable amount of pressure on it it slows nicely without any noise. I was careful with the brakes for the first 500 miles or so, not that i ever need to use the rear too harshly anyway. Any ideas what it may be?

[sputnik]

Did you give the brakes a bit of a strip down/clean up/regrease etc at the same time? Is the disc getting hot? Could be slightly gunged up pins or a sticking piston and the new pads and disc are just making it more obvious than before. A general clean up and greasing may sort it out.

A bit of copperslip on the backs of the pads may also help with various honking/squeeking noises if you haven't already done so, but I'm guessing you'll already have done this.

Failing that, perhaps wheel bearings or wheel alignment but sounds less likely...

Just took the caliper off yeah and gave it a general clean and copperslipped the rear of pads. Used copperslip for the pins as didnt have any RRG, we have some now so is it worth taking it off to regrease if my problem persists? I guess it could be totally un brake related but then i would expect symptoms all the time?

[johnnyrod]

I know the pads are new but it's worth giving them a taste of sandpaper accross the faces, and chamfering the edges a bit while you're in there. Copaslip is fine for the pins, just don't get it on the pistons, use only red rubber grease there. The grease on the backs of the pads is mainly for thermal transfer.

CB500s are known to get a bit of corrosion behind the rear disk which makes it feel like the disk is warped. It's probably worth taking the disk off & cleaning the mating surfaces with a bit of wet and dry.

there was corrosion on the rear of the disc where you say but i took that off when i put the new disc on.