What's make this noise?

 Please, oh please, do not try any of the above "solutions"! You will kill yourself. Full stop. I'll put this bluntly: disk brakes squeak. Thats just a fact of life. If you have metallic pads, then the squeaking will be worse. Here is my sure-fire fix to eliminate (or at least manage) the noise: replace your pads, use a liberal amount of sandpaper on the braking surface of your rotor, clean it with proper brake cleaner (rubbing alcohol will work as well, but it won't clean anywhere near as good as brake cleaner, as guess what? Brake cleaner is designed to clean brakes - big shock there), and wipe the cleaner off with a dry, lint-free rag. Ninety nine percent of the noise should be gone at this point, however, if the noise is still there after doing the above, then you may need to look into replacing the rotor as well, as they do tend to wear out over time.

If you need any further help, please feel free to contact me directly via private message, and I can walk you through anything you may need further assistance with.

 1. Never sand your disc. If if has sharp, chunky edges sticking out get a new one.
2. Make sure your disc is not bent. (release calipers, spin wheel and see if caliper moves. If they do = bent rotor) Try to rebend or buy a new one.
3. Clean rotor and pads with rubbing alcohol.
4. Wipe with a clean rag.
5. Never touch the rotor with your fingers, belive it or not, grease will transfer to your rotor from your fingers. = Sqeeking sound)
6. Re-open brake pads with a wedge so there is more room and so the caliper fits back nicely.
7. Release top screws and pump brakes untill firm, hold brakes down and close top screws. (b]Note this is for Hydro Brakes

 i fon sa parceque i vibre.... i a surement un slack a kkpart dans ton calipper.. s sur ke si tu fais inke accotter les pas sans faire une pression sa vas faire sa .... nimportekel frein fais sa ... din aitre coté c bon sogne ke tes frein fasse sa parceque sa veu dire ke tes pad i s'accroche au disque ....

 something noone has said check the disc bolts make sure their at the right tork and if not that adjust your brake its just rubbing, oh and do not use anything but rubbing alcohol to clean them automotive brake clean alows them to slip and will ruin your brakes, if none of this works ride fast and grab the brakes if their new they will make noise sometimes

 well if it only happend when your pulling your brakes its that your rotor needs cleaning and its sliding across the pads. and if your not pulling your brakes your disk is bent

 best thing to do is loosen the bolts connecting the brake to the fork. tighten the pads as tight as possible then retighten the brake to fork. loosen pad pressure then adjust for braking power

 thats just normal....metalic brake pads tend to be noisee, you can get some organic pads but they wont perform very good in wet conditions.

 the howl/squeak is just the pads doing there job, if there organic/sintered it can be very loud! Though After a few rides it should quieten as the pads wear a bit more.

 when you put the brakes on if you used automotive brake clean the noise wont go away youve gotta use rubbing alcohol to clean the brakes and stop it from vibrating

 its the pads on the disk brakes m8, im having exactly the same problem, does it happen when u brake really gently?

 i think your disk is bent or your brakes are pinching the disk two much so it does that

 definately a bent rotor cos u can hear the noise gettin louder as the disc rotates.

 it must be your disc that is bent

 use rubing alchohol on the disk

 have you cleaned the disc?

 if ur brake still makes that noise u should try sanding ur disk

 yess I did everything...

 def bent disk bro

 its a bent disk clearly

 if its disk its cuz the might need to be oiled or they could be bent.