Hi guys....................I had exactly the same problem in my Funtana 90, an Up Roar and OMP Katana 46. The problem here is lateral balance.
All planes with side engine the right side is heavier than the left....so when you pull hard the plane has this tendency to right snap.
When balancing your plane don't use the engine shaft to hang the plane.....this is not the geometrical axis as it normally has a right thrust angle. You need to find the exact long. axis and then use it to balance the plane.

Marcos