In lieu of a heat gun I tried the toaster-oven method, which didn't work even at the maximum temperature setting. Eventually I resorted to blowtorching the crankcase in the past to get the bearings out. They still wouldn't dislodge, even after getting the entire assembly hot enough that it was smoking and the bearing seals were melting. Never had to do that with a Toki engine, the bearings always dropped out easily. I don't know what Picco does when they install their crankcase bearings, but they apparently really don't want them to ever be replaced.

The engine is discontinued, so I have two reasons for not replacing the engine outright: 1) new engines are getting harder to find, and 2) OFNA is currently offloading their spare parts at a huge discount so I ordered a bunch. No crankshafts though. Also, if I bought a new engine I'd still have to deal with the impossible-to-remove crank bearings, which I want to replace partly so I can use ceramic bearings for longer lifetime, and partly so I can use a metal-shielded front bearing because this engine keeps blowing off the rubber seals on the stock bearings. No idea why that's happening, but a metal shield will never come loose.

So anyway: How can I tell if a crankshaft is too worn to be reused with a new crankcase? What are the telltale signs?