which is best brake fluid?

On my KZ project i have Grimeca calipers, aftermarket front master, OEM rear master cylinder and plumbing it with Goodridge stainless lines. I know the synthetic is paint safe, so i want that. Is there much difference between the DOT 4 and DOT 5. Im using Belray fork oil and I know Belray is a good overall product. Thoughts please..........

Google up "brake fluid" and start reading. Tons of info available.

DOT 4 is what I recommend. It's almost identical to DOT 3, just updated to have a higher boiling point. Something like 99.9% of all vehicles sold the world over use this kind of brake fluid. DOT 5 is not compatible with 3 & 4, and has drawbacks like a spongy lever feel and the fact that moisture that gets into the system will settle down in the bottom of the system and cause corrosion. Water will get into the fluid with 3 & 4 too, but a simple fluid flush will get rid of it.

ok, i understand more now. ill do the dot 4. any brands stand out more than others? i want to use the best. i looked at Lucas and some other brands.

I've been using Prestone Synthetic DOT-3, and it works perfectly fine in my KZ650-C1. Ed

tomsbadkz wrote: ok, i understand more now. ill do the dot 4. any brands stand out more than others? i want to use the best. i looked at Lucas and some other brands.

Any brand that meets DOT 4 will be fine. If you want to split hairs there are some brands of DOT 4 that have a higher boiling point that some others but that's not significant on an old vintage bike. You would be better off focusing on changing the fluid every 2-3 years or so.