mindey, he wants to know if it's possible... which of course it is:
YouTube - Motorized Bicycle Schwinn OCC Stingray Chopper
Donk do a search from the google search at the top on 'stingray' (all links will bring you back here) and you'll find others that have done the same thing you want to do. The only extra I can think that you'll need is a special plate for mounting 2 strokes to that frame. But whether you're going 2 or 4 smoker anything is possible.