If you look under your seat where the carb is, that is the limit before you suck water through the vent lines. Also there is the pull starter witch may or maynot leak water into your crank case. As far as I know that is all.
That would definitly be worth it. I just wish I had the balls to take it apart and seal itI've also seen a thread or two about sealing the pull starter. I have'nt done mine and so far with water up to the handle bars no water has goten in the crank case yet. nock on wood. But I think all you need to do it is a tube of RTV and a few minutes.