I saw a post from someone else and it didn't get very far. So I'm going to try my luck.

I have an 87 CBR600 RR. The engine is toast, let's leave it at that. I ask of all you who modify your own bikes, what engines are compatible with the frame, if not another 87 motor? Any links to threads that have answered this question, are still helpful. Case in point, before I drop money on another motor I want to make sure there's a snowballs chance in hell that it can be done (I'm willing to put in the effort.)and if possible, the range of motors that are compatible.

Thanks in advance for the help.

 

Replacement within the same generation should work. I've seen an '87 w/a '90 motor. The owner also replaced the wiring harness. I don't recall if the owner had to massage the engine mounting points but it seemed like a fairly straight-forward swap all things considered.