Well, I've broke two crankcases in as many months. The first one was in my truggy and the rod decided to leave the crank at top speed going down the strait. Not the sound you want to hear. 30,000 rpm to 0 in a millisecond. The rod punched a hole in the case.
Now, just this evening, I was replacing the rear bearing and con-rod in my buggy Arrow and pulled the bearing and was cleaning the case and what do you think I found...

A crack on the inside running along the motor mount. You have to zoom in to see it.
Now I'm down to one Arrow left that's in my truggy that replaced the thrown rod motor and it was involved in a wot run away with less than a gallon on it. Needless I could and did remove the break-in shim after that
I think I'm gonna try to repair it, weld the outside and grind smooth. I'll see if it will hold up. I like these engines, I bought three before they were available to the general public from Jaz240.
I guess I'll have to throw my backup motor till I get this worked out.
Cheers
Brian