I had a Webra .50 on mine and needed to move it farther forward. I don't remember how far though, but the prop washer was about 1.5" from the front of the plane. Before you do that though try to get the battery in the tank compartment (mine was under the tank) and right up against the firewall. Also, I don't want to tell you where to set the CG but I had mine almost an inch behind the recomended point (I started about 1/4" behind it for the maiden and keept moving it back until it flew inverted hands off).

I hope this helps