Hold the tip of the SG shaft and move it slowly in sideway direction, not rotate, not back and forth but sideway. If the bearings are worn, you can feel that the shaft can be move in sideway direction. If this is the case, the bearing has worn down. A badly worn bearing may release a lot of metal debris which is harmful to your engine to the piston/sleeve and combustion chamber. This is just a simple and quick way to check your engine bearing.
Originally posted by Motorman
this happens more than you think and causes serious overheating issues as the crank starts to rub the case bore. It also kills low end torque as it pushes the crank away from the critical sealing window on the intake side.