When we got out falcon 110, we put it together and ran it on our long gravel driveway. It was so unstable that I about flipped it. It would dart left or right at every bump or irregularity. It was scary to ride faster than half throttle in second gear.
I checked the toe measurement on the front tires and found that it was toed in. I measured inside to inside of the front tires, at the front of the tire and at the rear of the tire at spindle height and found that it was toed in about 3/4 inch. I loosened the jamb nuts on each of the tie rods (a left and a right hand thread) and turned them equally to shorten the tie rod length until I got about 3/4" toe out. Now it drives straight and stable. Huge difference!!