I just changed the bearings in a saito .50 and the hardest thing I found was getting the drive washer to come off,I used a lot of heat and hit it with a hammer hard enough that I was worried about bending the crank( used a 7mmx1 nut to protect the threads),I used a battery terminal puller to no avail until the heat got right.

I heated it with a propane torch. the rear bearing almost fell out when the heat was right,just bang the back of the case against a wooden table/workbench.

I used a hardwood dowel to drive the front bearing out after heating the case.

the crank then went to the wire brush as it was as rusty as the bearings.

after heating the case in a toster oven the front bearing went in easy,the rear was a little harder to get in but an 18mm socket fits against the race perfectly(heat and drive in)

I got it all back together,adjusted the valves and she runs like a top on the bench.

now trying to get the plane ready that it came off of