I didn't want to say it before, but since Jeff raised the issue... There has been some discussion that the counter balance beam is not stiff enough and is actually vibrating in bending or shear. IF this is actually happening then YOU ARE IN FULL AERODYNAMIC FLUTTER and may be living with a very dangerous situation. I don't know how to approach the solution other than to say that I hope that: 1) you're flying with a parachute, or 2) you have an auxiliary roll control device hooked up, or 3) you can fly without that aileron. I tend to doubt the bending theory because I think the vibration would then have been endemic to the class, but it's well worth investigating.