there is a company that makes cases for mountain bikes there waterproof and tough as nails. they are for airplanes.and they make it for each bike. google
bike cases and try and find it. im sure if you asked them and brought your bike over to them ( broken down) they would make a case for the frame and rear arm with no tires in case and possibly front fork laying under frame and arm.i cant find it but a huge downhill mountain bike is not much smaller in length then a drz400.
is it a drz400SM? just wondering because my wr250x breaks down pretty small i have not ever put it on a boat but with the front fork and rear arm off its not to big. and the tires.
i want to see a picture of the busa on a boat. that is pretty impressive.