The reason that there are so many "banshee" problems is because of its life span. It's the longest production quad. Everyone had a banshee. When it came out it was the most badass thing to hit the market. So you ditched the 3 wheelers and the 250s and got a banshee. So now since it's been around so long, you have 15 year old kids that have only owned a 400ex telling you banshees don't like water, they are hard to tune, there temperamental, they don't like the cold and so on.
Like stated, start any motor, open the carb and just out of a mister bottle spray water into it. Sounds stupid right?
So tell me one motor that does like water.