So, I upgraded a Motobecane 50v with a MBK Magnum Racing XR engine and it's slightly slower now and smokes more at idle. Power is decent. I have narrowed the issue down to either the timing or rings(compression seems okay though). I have never timed a CDI before, but think I could do it, just need to find the correct timing measurement.
It appears to be difficult to find timing information for the MBK Magnum Racing XR. I think 1.7mm before top dead center might be a decent guess and is what I think I will try if I can't find any info.