brake fluid dot 5 or 4?

Im useing a honda blackbird front mastercylinder on my shovelhead trike with shovel calipers. Honda uses DOT4 brake fluid, shovel calipers uses DOT5. Which fluid should i use & why? Thanks

[kevscrivener]

Originally Posted by budbombpipe

Im useing a honda blackbird front mastercylinder on my shovelhead trike with shovel calipers. Honda uses DOT4 brake fluid, shovel calipers uses DOT5. Which fluid should i use & why? Thanks

ALWAYS use DOT 5 in Harley brakes. Something to do with a higher boiling point. and make sure it's DOT 5 and not DOT 5.1; they're different animals.

[SJC69]

If the master cylinder and brake calipers have been used and one has used DOT 4 and the other DOT 5, you can not use them together unless you replace all the seals and thoroughly clean all the old fluid out of them.
If not the seals will fail and quickly as DOT 4 & 5 are not compatible.
If new no problem.