ORIGINAL: derftl56
It is a humming bird. As you are facing the tail the rotor is to the right. It rolls to side. The control unit is in the front of the helicopter, could that be part of the problem.
Hummingbird v4
Hummingbird 3D Pro
Hummingbird v.3
Hummingbird CP & FP
So it's a "hummingbird" is it?
Can the roll you speak of be countered with stick control? I'm trying to get the feel of the severity of roll. If it's just a minor nuisance roll you can just piloting the heli by moving the stick. If it's a little more than that, you can adjust the aileron trim (more left trim) on the TX and take some roll out. If the roll is so severe that full left trim and full left stick is not fully correcting the roll, then you need to make trim adjustments on the heli.
The hummingbird is eCCPM. It requires both the side servos to produce the aileron (roll) function. You need to change the length of these swash linkages so that the swash tilts more to the left (while TX stick and trim is centered). So shorten the left linkage and lengthen the right linkage by the same amount ... go in small steps.
Good Luck,
d.tipton