I have my AT 70's engine stripped down but the two crankcase still together, there is some side play on the crankshaft.
If I hold one end of the crankshaft I move it backwards and forwards a little bit.
If I push it to one side I can get a 0.4mm feeler guage in between the bearing stopper and the bearing.
I can find nothing in the service manual about this, so I presume it has to have a little bit of side play?