Rear brake partially binding

[Kookas]

The rear brake on my GS is binding through part of the revolution, and spinning freely through the rest. It will spin maybe 1 turn with a good push. Are there any cheaper possibilities to investigate apart from a warped disk?

[Kilted1]

There's a few things it could be, but a warped disk is the most likely.  Others are things like wheel bearings, siezed caliper, bent wheel, chewed chainring, wonky tire, stick in the spokes... 

Have you felt a pulsing in the brake pedal?  That would be a clue.

Get it up on the center stand and sit on the ground behind it while you or a friend spins the wheel and have a good look to see what wobbles.  If needed, you can tape a pencil or marker to the swingarm so it's juuuuuust touching the rotor, then turn the wheel.  If it's bent, you'll see it in the line getting thick and thin.  Clean it off with brake cleaner before riding, or better, don't ride it until you get the rotor fixed.

[Kito]

Hey Kookas...

Have you done proper maintenance you the rear caliper lately? I am concerned that maybe the pistons are too dirty ... maybe not releasing the pressure after the master cylinder have been relieved...

[cbrfxr67]

wheel aligned ok?  my little bike was shhhh shhhh shhh shhhh all the way down the street.  PO had the wheel off alignment.  Fixed that and all's well.

[Kookas]

I have been meaning to replace the rear caliper for ages actually as I tried to bleed it but the nipple was rounded off and rusted on so didn't manage to. I'll do that after payday and see how it goes. An obvious solution maybe but the fact that it's rubbing unevenly has had me wondering if that could really be it.