I tried to import a fbx file from Autodesk maya lt 2016 to Unreal engine 4. It was a knife model and it looked fine in Maya but when i imported it to UE4 it looked fine, but the other side was invisible.
Check normals direction in MAYA. If you modeled a half of your model and then duplicate with negative scale, normals has same directions as original the half of your model.
I did some research about it and. as far as i know, the normals should be fine
Object: http://static.tf3dm.com/models/qrz5s8ft22v4-Karambit.rar Screenshots: