i just bought a 2013 beta 125 factory but the brake arent so good, so i was wondering if anyone know how to make them more responsive?

Fit new ones.  My wife's 2014 Evo had a poor front brake and I have replaced the master cylinder with a braktec (like on the new Beta factory) the disc with a Galfer and a full rebuild of the old Grimeca caliper.  The brake is now as good as my TRS (braktec).  I think the braktec caliper would probably fit as well if you want to go the whole hog, but it would need a new brake line as the banjo is a different size.

To start with I would check the level of the brake fluid!  If ok then fit a new set of Galfer brake pads and clean the brake disk with some brake cleaner. Spray the cleaner on a rag, then rub it on both sides of the disk.  (Don't spray it directly on the disk as you will likely wash the grease out of your wheel bearings).  If this still doesn't improve matters, then replace the brake fluid.  If still no luck, then get a brake seal service kit.  If you are still not happy then replace as stated in the above post.  I had a (new) 2014 Evo and the brakes were fine.

What I would do in order : Take the pads out check them for exess dirt or oil, sand them on a flat surface, clean the disk, and do the cold water treatment: ride and drag the brake untill the disk is hot then drop cold water on the disk. 

Guy

I had this issue on my 14 beta evo 300. Re bled. No fix. New pads and cleaned the rotor. Little better but still not great. Went to a galfer rotor and bought the jitsie race pads. Wayyyy better now. I’m guessing the pad compound was the biggest difference but would try that 

Check that the pads aren’t getting caught by muck in the caliper and are not pushing fully/squarely onto the disc. Make sure the pad retaining pin is clean and not damaged. They can rust and pads sit in a notch. After that change the fluid. After that seals at either end if you have leaks. It really pays to service brakes every once in a while. A toothbrush and brake clear are very useful.