I heard marbles rattling in the engine and it just stopped.

[Easy Rider]

Originally Posted by tommyjoebilly

Funny you should say that, EasyRider!

But the noise was much "heavier" than some little bits of metal, unless it led to larger pieces (gears?) breaking down??
Thanks so much, Easy, for your post!

It is very common for the first post about any problem to leave out some detail that later turns out to be important.

Given what you just said, I think you should take a look at that starter again first.
Even though a damaged flywheel might sound easier to fix than a trashed top-end, it may not be because the case might have to come apart to do that.

Regardless of what the cause turns out to be, it is not likely to be easy.

Sorry for your pain.