It's funny but we always think of the Bing as being a primitive carb, yet all of my Maicos run better then my friend's Gassers, TMs and Huskys. They always seem to be chasing some elusive setting that my bikes already enjoy. As for a flywheel weight, I don't think that the Maico would need it, the bikes are already very smooth and you'll find yourself going alot faster then you thought - the speed kind of sneaks up on you and you have to be careful.
The Koestler Maicos are very exotic looking motorcycles and will atract attention, unlike the KTM which are d*mn fine motorcycles but are a "Dime a dozen".