Axial slops in the generator belt pulley?

[david.skinner]

I took the generator off my 81A because I could hear a noise like a bearing running. Turns out the front bearing on the generator was fine but on reassembling the pulley mechanism I have about 2mm of axial slop - like its missing a washer or similar but I'm sure i haven't lost a part on disassembly. It strikes me that this might be intentional to allow the pulley to align with the belt but I thought I'd better check.
many thanks
Dave NZ.