Some guys have drill and threaded a 1/4 coarse thread and put a really short bolt with a rubber washer in the hole.

Others buy a Grizzly 660 drain and use that (drill hole).

One guy installed a petcock.

I got a lot of water in mine once. revving it in neutral worked, but took a while. If I got water in my belt more often, I would probably use the screw and rubber washer idea.

 

The new 700s have a drain, might be comming out on the new 03 650s.

 

I like to remove the cover and dry the belt completely, so it won't
slip. It takes a minute to remove the cover. Belts are not cheap. I am
going to snorkle the intake and exhaust, can't stay out of the water. I
drowned out the other day, I guess it was water coming back the exhaust
at idle. It was slugged, I should have jumped off, as it floats a little.
I could have kept it running. I floated it back to shallower water and
pulled the filter cover to look for water. It was fine. I then started it
and rode out, then pulled the primary cover and dried it out. There was some water in the oil, so I changed it when I got home. I will change it
after another hour of running, to make sure it is all out. No big deal,
I don't think I did any real damage.