Hey everyone so I have a 2012 Ninja 250 10k miles and after the winter I noticed that the bike has been very difficult to move even when in neutral. I brushed it off and fast forward to some riding I noticed the bikes front brake gets extremely hot after each ride. So I decided to take apart the the brakes and see whats up. Sure enough I pulled the brake lever and one 1 piston was moving (the right one) The left one just stayed there. I tried cleaning the pistons best I could and still the left cylinder wasn't moving at all. So thats where Iam at.
My question is that there seems to be some white and black stuff lining and maybe a little bit of rust? Would WD-40 or brake cleaner be something I could use to clean in the cylinder deeper? Because I wasn't able to really get to deep because the cylinder wouldn't move out. Any advice would be appreciated.