Main Forum - Poor running MB5

Hi,
My MB5 is still running poor. Very poor power, and misses at high RPM.My 20mm Mukuni is new and clean. Starts and idles well. I put the stock carb back on and it still ran poor.
I have checked out the wires...put a new plug wire. Coil and CDI are good. My fried has advised me to advance the ignition by turning the stator, (even suggest drilling new holes to advance it) Has anyone done this?
My motorcycle mechanic friend suggested I may be sucking air in through the main seal behind the stator and rotor.
Thanks,
Rick