I recently installed a new motor in my Raptor (ThunderTiger 39). Now i seem to have intermittent interference. Throttle and pitch change and tail rotor behaves uncontrollable at times. I have since learned that loose parts can cause interference i.e. metal.
I just checked to be sure the motor is secure and found that I could tighten the mounting screws almost a 1/4 turn. Also I didn't have a rubber gasket between the muffler and the engine. Could that cause a problem, even if there is no noticeable play between the muffler and engine.