Depends on the way the head(s) are set up.
http://www.mutoh.com/kb/entry/95/
So, on a 6 head machine, FIIO, Toucan LT, you can syringe one color at a time from the bottom of the cap.
On a 2 head machine, FO Jr, you can syring K at one time, but only all three other colors from the bottom...