I've been having this ongoing "issue" with my Ercoupe since I bought it about a year ago. Recently just completed an annual where the A&P went through the service manual procedures for ailerons and the nosewheel and we still have the same result.
Basically, I have a right turn tendency. I have to keep a little bit of left pressure on the yoke to keep us wings-level. However, if I hold the yoke exactly straight I am in a slight left turn. And when I let go, the yoke centers itself slightly crooked and we go into a right turn. Nothing extreme, but enough.
The service manual also has a recommendation for bending the trailing edge of the aileron as a means to trim out "wing heaviness", but this does not feel like strictly an aileron issue to me. Although I could be wrong. My A&P are I at are a loss, does anyone here have any ideas?
A video is worth a thousand words...
Here is a second video where I focus more on the yoke itself
