front break caliper

Remove the pads....pump out all the pistons (not all the way out) spray with wd40 and clean with a tooth brush round the pistons and inside the caliper....clean all wd40 off, smear brake silcon grease on pistons and push back into caliper.....fit pads and it should be sorted.....worst thing is you might need new seals

Do both the left and right calipers

As above

Only I'd use proper BRAKE & CLUTCH CLEANER not WD40 as this leaves a residue behind and may attack the seals.

I trick I use is after pushing the pistons as far out as is prudent,use a spray of cleaner and scrub with an old toothbrush,then soak a length of fine string /twine with cleaner wrap that round the piston and in effect floss the thing.

After working your way round each of the pistons in turn you should find they slide much easier,also using proper cleaner means you can get ALL the crud off the calipers and pads and they should come up looking like new.

Also clean the pads and smear ( lightly ) some CopaSlip on the back and sides of the backing plates.

Remember to pump the lever before riding to make sure all the pistons are in the correct posn. Job done :thumbup

PS: I also de-glazed my pads by laying a sheet of Wet & Dry on a mirror and rubbing the friction face until I could see a change of texture/colour.

If you do this be aware you are effectively using new pads and they may need bedding in !!!

YES! I believe that's one of the things I suggested could be doing it. I had a ZX6R with terrible brakes and have lots of experience lol!! I ended up stripping them and replacing all the seals. That was fun.

As long as your calipers are just a bit sticky you should be okay with doing as suggested above. USE brake cleaner though. WD40 isn't recommended anywhere near your brakes, not only might it attack your seals but it mightn't do your braking any good if it contaminates the pads or discs. Brake cleaner will be fine if you get a bit overenthusiastic!!

I use a socket in one piston to keep them apart whilst I push the one next to it out, clean then push in and out, wipe it, smear red rubber grease, then push in and out ionce more just to make sure it's properly free. Then do the other piston. Then do the other caliper.

MAKE SURE you pump your brake lever to get the pads in contact with the disc before you move your bike. It's not a good thing to forget I should imagine!!!