Right, I would expect to have to put in a little trim here and there, but my problem is, its so bad I CAN'T trim it out!
Yea, I think I failed to clarify. That is only when attempting to bank to the right; when banking to the left it rolls just fine! Its just that the ailerons have a hard time counteracting whatever issue it is that is currently causing the plane to bank left!
This may seem obvious but many times I've over looked the obvious. With slow response in one direction there may be a servo problem or linkage binding. Check by simulating flight loads on ailerons while moving the stick. Pay particular attention to servo responsiveness, unusual servo noise or binding. Make sure you do this under load. Hope you work it out.