By constant left cyclic input, I assume that you are talking about yaw, because the CX3 is a co-axial. If the problem is beyond correction with trim, adjust the proportional mix pot on the 3 in 1. That adjustment is touchy. That pot is fragile - Mess with it too much and it will break. I recently repaired a CX2 whose former owner diddled with the pots so much that I had to replace its 3 in 1. That person failed to notice that the lower rotor head was broken and essentially wore out the pots on the 3 in 1 trying to fix its misbehavior.