brake fluid-what and why?

[zed]

Originally Posted by ZUKIMON

I'm still unsure about my fluid. My 929 says DOT 4 on the caps, and I have a quart of DOT 4 Castrol Synthetic sitting here on my workbench at work. Is there a DOT 4 that's not synthetic? Will this be OK in my bike? I've never messed with anything other than DOT 3.

without looking it up somewhere I don't know the answer, did you look on the container and see if it says not to mix with other DOT4 fluids?