Looks exactly like the engine on my 7 KW generator.
Genuine clone engine, LOL.
So far mine has been very reliable and saved all my foods for some 8 years now.
We enjoy (?) some 5-7 power outages per year.
Is the shaft tapered? AKA can U repurpose it? (often gensets use tapered shafts)
As crude as it sounds, you can fire up the engine and carefully file away that tapered end to a usable diameter.**
Otherwise dismantling and taking the crankshaft to a machine shop is the proper way to go.
** poor man's lathe, LOL.