I would look for something wrong with the mate surface on either the regulator or the case. Also the air box parts. These pieces can be tightened up wrong and warp the part this can cause leaking. You don't want to even come close to torque enough strip threads. My guess is you may have tightened too much or maybe something else has happened. You can lap the mate surfaces if you are careful. I have done this many times and it will solve the leaking problem. If you don't have luck I would contact Service and they can help you out.

Fuel leaking anywhere there is a gasket will not allow the engine to run properly. This should not be hard to solve.

Inverted mounting is not an issue with the YS engines. They are actually designed around this with their pressurized system.

Troy Newman
Team YS Performance