Alright everyone, thanks for all the input!
Today when my fiancee was at work, I did most of the job myself. I am a very concrete, black-and-white person, whereas she is abstract and artistic, so it took her help to smooth out some of the bumps in the road that I encountered. For instance, she figured out how to remove the rear chain guard retainer without just cutting it all up (as I wanted to do), and she removed the muffler when I was content to keep bashing it with a sledgehammer.
Day 1 of the project is over. Should finish it up tomorrow. I need to re-run the chain, check the tension, tighten all the engine mount bolts, run the throttle cable, wire the kill switch, then we are ready for a test drive!
Progress photos...
Trip to the local hardware store for two 3/4" ID washers, plus Lowe's-sourced clutch bolt and washer, equals success:
Tight fit between the engine cowling and footpeg...have to see how comfortable this is when riding. Messy background is due to wheeling the bike into the garage and then deciding to do photos as an afterthought.
Exhaust was originally bashed with a sledgehammer, then removed to fit in the frame. It was reattached after the engine was mounted, with room to spare. Yes, this will be replaced with a real pipe sometime before next spring.
Clean rear end with no plastics for the moment. I know I routed the chain wrong and under the tensioner, have to redo that tomorrow. Anyone want a nice, near-new stock engine for free? It's luring in the background here.
Overall a nice fit, I am pleased. Thanks to all of you!!!