What tool do you use to measure crankshaft runout?
Similarly one may ask, how do you check pinion shaft runout?
Measure the runout with a dial indicator that is mounted to the motor case. With the bike in high gear and spark plugs removed, roll the rear wheel so that the pinion shaft turns and run out can be measured. If runout is under . 003″, it's a go.
Considering this, how do you check crankshaft straightness?
To evaluate the straightness of the crankshaft, the shaft should be supported by V-blocks positioned on the end main bearing journals. Position a dial indicator at the three o'clock position on the center main bearing journal. Set the indicator at 0 (zero) and turn the crankshaft through one complete rotation.
For radial run-out, start by mounting the bearing so you can rotate either the inner ring or outer ring, depending on which raceway you want to measure. The dial indicator should be held perpendicular to the surface of the raceway.