I attach a picture of the CDI Modification. Be aware that my (1992) SACHS is a model 301A with a BLUE CDI unit. Evidently the blue CDI is the most common but there are RED and BLACK CDI units.
For heavens sake do not go drilling holes into your unit until you have comprehensively researched the subject! I went so far as to JOIN the Dutch Saxonette forum (I understand German but struggle with Dutch) and having babelfish translate the posts until I understood what they were on about.
What I found was, with few exceptions, all the guys, who after reading the quite amazing increase in performance obtained by drilling the CDI came back enthusiastically relating their experiences. I also learned there was a Dutch guy, name Jan jhcvaal@kabelfoon.nl who is the World expert on these and will supply a modified CDI for 45 Euros plus postage.
From what I can tell the restriction simply limits the motors RPM. Take it away with the drill and the little motor behaves as its designers intended. There is a whole WORLD out there of which I was unaware! All these guys who love mucking about with tiny motorbike engines, I love it! According to Jan a few other mods and you really get a tune out of the Sachs. He reckons the best speed so far obtained is 58Kph! I hasten to add that mine runs to about 30 Kph or maybe a little more. I don't have a speedo and the roads around here are typically Australian rough bitumen. At anything over about 23 or so (a guess) there is considerable vibration through the handlebar of the Bike which is tiresome. I am thus content to tootle along at the lower speed and watch the scenery pass and since the modification I seldom have to pedal unless the hill is quite steep.
I cannot say what effect (if any) it may have on the Rotary made Motor. I understand these are exact ASIAN built copies of the Sachs 301A motor. If so they should behave similarly. Beyond saying beware, that's all I can do.
All the best to you.