Wee pulls to the left

Hello! My Wee pulls to the left when I let the handlebar go, I have to lean a lot to the right to keep it straight. I also having some trouble to keep it in straight line, seems to have a very slow weave. Steering bearing are not tooo tight or loose and turn smoothly. Wheel bearing are fine, bike is a 2011 Wee with 5000 miles. OEM tire in good condition. Rear wheel adjusted to have sprockets lined, mark on swingarm are pretty close, I assume rear wheel is centered. Bike is stock except a fork brace. It has done it for the last 1000 miles was fine before. Never dropped it. Rear shock full preload, front fork OEM setting (3?) 210LBS no luggage or topcase. How can I improve it?
Thank you!