Check flywheel runout of the pinion shaft while assembled in engine case; check the amount of gear lash on gear driven cams used in some Twin Cam engines. By using JIMS Tire Rotator P/N 461085 you can remove most all of the stress being applied to the flywheel by not rotating the engine with the electric start motor. Made in USA. Flywheel Runout (Trueness) Inspection Gauge