The 2 bungs under the Adventure Island seat are painfull. The area fills with water and you get a wet arse. This following mod is simple and cheap to do. It involves replacing the bungs with simple valves cut out of a cheap syphon pump. When placed properly from the underside up, they not only drain out the water when your moving, they also seal when your stopped so no water gets back in.
Here are the picks of the valve system for the seat well. The bungs are gone completely replaced with the valave from the cheap syphon hose. This works like a venturi system sucking any water out when your traveling.
You need 2 cheap syphon pumps.
Cut out the exit valve and the surrounding plastic.
Insert into the bung hole and seal with silicone.
The valve flap must be facing backwards.
Smooth the silicone out and there you go. Simple and effective.