i just purchased my first ys and i haven't been able to make it work too well. i'm still trying to break it in. first the idle is all over the place, it wavers a for about half a minute then cuts out. that's just the beginning. the ys backfires so violently that it shredded by spinner and hurled it across the field. i've also experienced a huge clank when the engine siezed. now i'm nervous to run it again. are these experiences "normal"? what can i do to make it work? i am using 23% nitro spinning a 12 x 6 prop. My friend said i should consider running either lower nitro and smaller prop (which i don't think is necessary) or adding a shim to lower the compression rate (which i also don't think is necessary).