ReplicatorG have bugs in translating G-Code command into X3G, may cause over speed in tool changing sequence. 

Solution 1: Update ReplicatorG
Download [[http://www.malyansys.com/downloads/ReplicatorG.jar|ReplicatorG.jar]] and overwrite into <Install Directory>/lib.

Solution 2: Newest firmware have additional workaround to handle tool changing sequence for ReplicatorG
Reference to [[firmware_update_procedure]].