I have a new Moki 2.1 that has over a gallon through it. I am using a APC 22X8 and Bisson sports muffler.and can get 7500 RPM. The problem is at idle it is really rough. As l power up there is a ping ping ping sound untill abut half throttle. Sounds like pre-detination. Sometimes at idle it smooths right out, the way it should be and then starts to get rough again. Is it to rich at the low end. I tried turning it down, but it dies on me. It dies if l richen it as well. I have tried different plugs as well. I am using XP Sport fuel 10% nitro, 20% oil. Any ideas? Let it break in some more? To rich, or lean?

Thanks

Tim