Today, I changed the brake fluid of my Honda CBR125R. First of all, I changed the fluid on the front brake. To perform this maintenance, it is necessary to use a pipe, as shown in the picture. After turning the screw, and pressing the front brake continuously, the fluid flows in the pipe, to the PET bottle. This special pipe allows the fluid to be only extracted, since it has a "non return" valve.
The following picture better shows where the pipe has to be connected. On the bottom of the pipe (right side) the small screw is visible. To open it (counter clockwise) an hexagonal key is needed (see picture above).
When changing the new brake fluid (BF4/DOT4), the motorcycle should be on horizontal position (the picture below is not so good, since the motorcycle was not horizontal), so that it is easy to understand how much the tank is filled.
After filling the new brake fluid, the tank should look like this (the fluid level should be between minimum and maximum).
The complete operation took about 30-60 minutes, taking into account that I am not an expert (it was the second time for me to do this maintenance). In order to completely change the brake fluid, I used about 150ml of fluid (the bottle which I bought was 210ml). I wanted to be sure that the old fluid was completely drained, this is why maybe a wasted also some new fluid during recirculation. Anyway, let's say that 500ml are too much, and 100ml may be not enough, in my opinion. The best idea is to buy 200-250ml to make sure that you will not finish the fluid in the middle of your job.