Apparently guys, I did not get the nuts on the four engine studs that mount to the bicycle frame, tight enough. I have read on these pages, that the studs are weak, and should be replaced with 8mm diameter ones as said here. Therefore, I was careful in tightning them. When I completed this bike build, I was excited to go out for my first ride and it was so much fun, I ended up riding about 3 miles! When I returned, the engine was about ready to fall off! I was lucky to get back when I did.
Now with winter here now in Michigan, I think I will take the advise given here to replace those studs with 8mm ones. I checked my local Wholesale Tool supply store and they do not have any metric threaded rod, just SAE. So fellas, where do you get your metric threaded rod from?
Thanks as always, Karl