ORIGINAL: John Palica
My guess is you have the rotor timing 180 degrees out of phase. The port in the rotor should be starting to open as the piston goes up towards the compression stroke. That results in a low pressure in the crankcase causing the air fuel charge to rush into the crankcase through the carb. If it's 180 out, the rotor port will close as the piston goes up and opens when the piston comes down. As the piston comes down it pressurizes the crankcase and blows the fuel charge out of the carb.
indeed...thats why i asked if he had a disk rotor motor. I know i put my backplate on with the disk 180ยบ out and it would start, but only run for a few seconds, and very poorly at that.