I'm going thru a 81 FXWGand I found that the starter gear and jackshaft assembly is loose "I can grab theend of the shaft andshake it about 1/4 inch" the bike turns over and start'swith no issues. Is that much play normal?

04 FXDWGI
81 FXWG

Thats about how much play the shaft on my 68 has assuming were talking about the same thing.
With the outer primary off and moving the bendix drive end of the shaft. The needle bearing on the other end of that shaft isn't very deep and only about 1/2 - 5/8 " od. The main support would be when the outer primary is installed supporting the drive end of the shaft.
Boy thats a pain if you pull that shaft out to far and the gear and thrust washer falls inside the housing [:@][:@] at least it is with the prest-olite system.