Blocking the crank is an issue that should be bought to the attention off anyone that appears to not know about it.
Wouldn't it be a 50/50 chance as to whether the engine case or the crank wins the vacuum tug of war with the thrust washer?
If indeed the crank gets pushed forward.
A lot of noobs trying to remove a rms particularly on a clutch carrier bike might use the guide ring for leverage.
Shit, I did.
And I didn't know about blocking the crank.
And I pushed the crank forward without realsing it.
And I torqued up the clutch carrier with the washer sitting on top of the dowels.....
Lord of the Bings, kangaroo farmer