2003 Road King, new 21 mouse cams, new S.E. plate and pump, S.E adj. push rods, Street port heads, new valves, springs etc. Rinehart TD'S, CV carb with sporty needle, 46 slow 190 main. In second gear at a steady speed like around 25-30 mph. The exhaust note sounds like the motor is missing. Idles great and runs strong when twisted back. Just an odd sound that I cant figure out. New plugs, different needles in carb and shims etc. Still there. Not even sure it missing really but sure sounds like it to me. Have not changed plug wires yet..... Any ideas?