rear brake pads and rotor

Anyone have suggestions on why my rear brake pads have worn so fast and why my rotor is now pretty much toast?

2012 WR250r bought March 2012

I am now at the end my second set of toasted rear brake pads. 24000 km total. and now my rotor is toasted as well.
I am still on my first set of front brake pads (although they need changing soon)
I don't ride/drag the rear brake when I ride, so I know it's not that.

The first set of rear pads wore down fairly quickly after I went on the 2013 Roaming Rally in Ontario last June. The first day of that rally was brutal. Tons of mud bogs(I generally ride mud two or three times a year) and water crossings. I figured that was normal for the pads to be worn soon after that. they lasted over a year until that Rally, then burned out fast after that.

What is the consensus on dirt in the rotors/pads. is it really that harmful to the disk and pads, or might there be another issue at hand?
The second set of pads has not even lasted 8 months and are now pretty much unusable.
I kind of assume the pads would get worn faster with a worn rotor, but it seems excessive to me.

What's the 'toasted' rotor look like?  Discolored (blued or burned) or grooved?  Might be worth your while to pull the rear caliper and see if the pistons are moving like they should.  Grit/grime/water/heat can certainly gum up the seals and pots.  Also, if your brake fluid is old, it has probably absorbed some moisture. Water expands when heated, and it's somewhat common for a brake caliper with neglected fluid to tighten up when it gets hot. If you don't ride/drag the rear brake, it might be doing it all by itself...

You also need to grease the caliper slide pins once in a while.

The more dirt the rotor and pads see, the quicker they wear out.
Some riders get less mileage than that.

Thanks for the responses guys.
The rotor is worn unevenly. (Grooved unevenly) It's grooves are deeper in some spots than others. Like its actually noticeably thinner in the center of where the pad rubbed than the edges. But overall still thinner on the whole rotor.

I try to get to the dirt as much as possible, and always seem to be in either sand or mud. I just have not heard of anyone else having much of an issue before.

Anyways, I have a new EBC Supercross Contoured Rotor - MD6319C on order as well as EBC X Series Carbon Brake Pads - FA367X

Hopefully i can keep these in better shape, longer. it starts getting expensive.

*I suspect that now that the bike is over 2 years old that I'll start getting parts breaking down more often.....dam!

I only got 2500kms out of my rear brake pads lol.

If you can get a solid rear rotor, the pads will last a lot longer in the mud /wet sand.

The slots in the rotor fill with mud and it grinds the pads down.

Im not sure what that ebc rotor looks like, if it looks like the glaffer wave rotors it will be an improvment over stock they dont have holes for the mud to pack into, if it has holes or slots like the stocker you will still burn through pads quicky.

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