FIRST, I strongly recommend getting to know your moped real well. See what kind of performance you can get out of what's already there. Try any (or preferably all) of the following. They WILL give you better speed:
- clean your points real nice and reset the gap
- clean and repack your wheel bearings with fresh grease
- clean your chains and give 'em some fresh lube
- decarbonize EVERYTHING (instructions in the Puch manual)
- get a new spark plug (I'd even go the extra mile with a new boot and wire)
- drill your carb and intake from 12 to 14
- get rid of the second half of your air box and replace the element with panty hose
- derestrict your exhaust
- change your gear ratio with a new, or like-new, sprocket
- probably some other things too. do a search...
My pinto went 28 when I first got it, but you could push yours into the high thirties with all of that.