250cc left crankcase cover keeps breaking

[dmr3073]

We have a 250 buggy and about 2 to 3 months ago we had to replace the left side crankcase cover because notice it was cracked in half.
After replacing we have only ridden maybe about 10 times since and we just noticed the new one has cracked again in about the same spot.
We are clueless as to why and know this is going to become expensive if we can't figure out why this is happening, since nice riding weather is starting to kick in. We can still ride it but know it's gonna become an issue. The only issue per say that may or may not have anything to do with it is the external reverse on this buggy you have to give a bit of gas in order for it to go into reverse and at some times it will slam into reverse or some times the if on slight decline and try to go in reverse it will become harder to do so and really slam to reverse. So not sure if that has anything to do with the crankcase cover cracking.. we ride in the woods on our land with cleared sections and hills not very steep.
But this biggies are suppose to be able to handle that.
We know we have been putting off getting a new reverse assembly, but want to know if that is our issue or what the heck is causing that to happen. Before we break the bank on having to replace constantly. The left side crankcase cover is a cf250 engine. Thanks for the help.