Sabs, I have done that mod before, removing the restriction right? The one I am referring to is a Puch Tech Bulletin that tells you how to convert a 1.5 hp to a 2 hp motor. I found it a long time ago, might be in the Wiki. It says to drill 2 10mm holes in the header pipe at 250 mm and 275 mm from the end. It also tells you what to do with the carb and air filter as well. It does not say if you drill through both sides of the pipe like the stock holes are drilled
My pipe came with on hole near the end of the header. I saw the version I think you are referring to with the restrictions in two holes at 250 and 275 mm from the end. I guess that means I need to drill all the way through.