Personally, I think you'd be wise to stick with what HD recommends which like others have said, is printed right on the MC cover. I'm assuming the engineers and designers at HD use specific types for a reason. My FLSTC uses DOT 4 and I see no reason to change. Stops my bike just fine! LOL JMHO

 

Yeah i need DOT 4 for what i am doing...and it seems though there are maybe some advantages using DOT 5.1 they are not big enough for the hassle so i will end up just sticking with DOT 4.

Is the DOT from HD good enough or should switch to Amsoil or something like that.