i ran an abc engine after letting it sit for a while without after run oil.
i spray wd-40 to break up the gunk, but got too impatient.
the engine ran fine for a while then started to overheat or dead sticks.
particles ruin the sleeving and piston.
a ring engine might do better, never the less the enternal of an engine
should be as clean as possiable.
i didn't soak the engine long enough to get the gunk build up in the bearings out.

you can soak the engine pretty much still intack.
just remove the back plate, head, carb.
do it a couple if times if you have too, be patient..it'll save you money and headaches.
you don't want to soak o'rings or seals or rubber parts

there's also a tiny hole on the bottom of the rod to allow lubrication
of the thrust bearing in the rod or (brass bushing). makesure thats clean also

flacon 5

if you remove the sleeving, it'll allow room for the rod to slide off the shaft.
the cranshaft then should slide out from the bearing.

i don't know if the bearing is bad.. you might what to reconsider
or look into the cost of the bearnings.
is the engine leaking from the front?
is the bearing actually damage?

use a wooden dowl to hammer out the bearing..the bearing gets destroy in the process.
but if the bearing was bad that wouln't matter