i was told this years ago by a anorak friend we all got em ,that you could fit 900 pistons into a 750 just to increase compression, but i would not like to try it myself.your best bet is asking someone who has already done it,i have a f2 engine and carbs on my sidecar unit , the only real difference is these carbs have an accelerator pump and considering the extra weight of the chair, they pull very cleanly through the gears with no hint of getting bogged down, my advice would be, forget the 900 pistons unless they are really cheap and the engine is already stripped down ,but i would certainly try the f2 carbs, come to think of it perhaps a f2 engine might be a better option.
