First, you MUST use the correct puller to remove the rotor. It screws onto those threads and you leave the retainer bolt in(most times) to bare pressure against. Danage those threads much more and you won't be using the puller. I think it's this puller but check the thread size first:

https://www.ebay.com/itm/353814474225?hash=item5260fc6df1:g:G9wAAOSwfzphutlC&amdata=enc%3AAQAHAAAA8K5gwLvNwDXRxgLKuzwZeirC6OyssieqVMHqa9sL9tIylXVcr%2FBBeuMMhiq1CVv6EmHkEp34BaNEvXm2HmjgRP%2B2y%2B0B3fZqcsUtQgWQyed%2FmDR3yffDvToMfvV6kQCn7nRpvfJ1h7EdqaucMS492rvAaFUZNtW7daBhKwA0gu9z6y8%2BUErG0lDLnZBc4WkzwK%2FZoAs12GnM%2Ful2CYP2RRLLf1vAHBuxh9hY%2BFxOTNA4g%2F5fsaKDaIYqlURDZ2UH2G7E5lyACRlsS1FFMceXokca%2FGnXcxa1nuGH4yqtJhEpYbRcZZrGAkW3k%2F0buvJpkA%3D%3D%7Ctkp%3ABFBM_Nioi5lg

On the crank/rod I always thought on those you replaced the entire thing with a crank kit. Look up rod bearings and if none are listed, nor separate rods or cranks, it is a complete kit/unit.

Thanks so much. All the youtube videos and other websites i found never showed that tool for removing the setup.
Are the retainer bolts you are referring to the allen Cap head bolts that go through the Magneto into the Flywheel?

Here is the Connecting rod image.

Hey guys.
I'm doing some engine work to modify the 500CC Carburated engine I have. I can't get the Magneto off the crank shaft. See image below. Is that black piece threaded on? Or is it pressed on? I used a gear puller and it didn't budge. But i also tried unscrewing it and it didn't budge. I hate to cut it off.

Any help would be greatly appreciated. I can't find much web or youtube support on this. It sort of seems people don't go as deep into this engine as I have.

Also, how is the connecting rod secured to the crankshaft? It looks like the crank is two halves pressed together.