The Honda 420 that I have been working on for quite a while now is finished. I used the parts and pieces from two wrecked engines to make one good one. One engine had a cracked piston and a faulty transmission, the other one had a good transmission and a bad everything else. Both engines failed from a lack of oil.
You can see the older posts about it here and here.
The whole project took about 25 hours of labor and $1000 in parts. It runs great now, like these basic Hondas always do. Most of the Honda models are not very high performance, but they all run great.