How big'ha engine can I put in THIS?

that cool. don't know what 's in it now but you could certainly go bigger:D

I know a friend of mine that has a SCOOTER (as in handicap style. but with 4 wheels not 3)with 250cc Honda engine in it. next time I'm up in Michigan I'll take some pic's of it. damn thing flies! he went to the Michigan downriver cruise with it and went all over the place. it's soooooo funny watching him do a burnout with them little itty bitty tires. I asked him where the wheelie bars were and he said they are next on the list after a bimi top (whatever the heck that is). he says he get pretty good mileage with it too! better than his battery one.