why does my static mesh have the black marks

I made this from a bsp brush and it looks fine but as soon as I turn it into a static mesh it leaves the 3 black lines no matter what texture I change it to why does this happen and how do I stop it? thanks

When you convert to a static mesh, the UV map in not usually very good. I found you always get overlapping or having faces too close to one another. You can export that mesh to a modeling program and redo the UV map.