When I was a kid my friends dad used to take his seat to try and stop him from riding so he just slapped a pillow on there and we went anyway. It won't look cool but you could ride. If you have the airbox still you will have to do something to allow it to breathe.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!