Check flywheel runout of the pinion shaft while assembled in engine case. Also checks the amount of gear lash on aftermarket gear driven cams for Twin Cam engines. By using a JIMS tire rotator ZPN 753615 you can remove most all of the stress being applied to the flywheel by not rotating the engine with the electric starter motor. Kit contains instructions, indicator plate, required hardware and a 1" dial indicator. Works on 1970 thru 1984 Shovelhead, 1984 thru 1999 Evolution Big Twin and 1999 thru 2017 Twin Cam.