Most of these tests have to be done with the bike fastened to a centerstand. Wheel bearings worn, especially on one side. Steering head bearing adjustment too tight, or bearings worn. Steering stem bent (usually after impact). Swingarm bearings worn or too tight. Preload or other adjustments in the forks not even on both forks. Front forks twisted (have to loosen all the clamp bolts, wheel axle, and fender bolts, then realign, and tighten from the axle upwards).