Guinness, it's good to drink.. but it is not a suitable brake fluid.. i just put EBC 'HH' pads on my bike and drained/flushed the brake and clutch fluids.. UGGH, it looked like Guinness beer.. the EBC pads have WAY more stopping power than whatever was on there before

if your bike is over 10 years old and you aren't sure if your brake fluid has been changed, DO IT, I put castrol GT-LMA brake fluid that exceeds dot 4 specs.. it's low moisture activity as well, and was 1/2 the price of NAPA brand Dot 4.. so guess which I went with??