My experience has been that at KDX is about water proof. What you do not want to do is run it with the air filter completely under water. It will suck water through the filter and into carb and engine. However, if it is not running, a properly oiled filter will shed water and the air box will drain it away. In just a very short time, it will fire up and never look back. I have dragged them through deep crossings with a dead engine and started right up on the other side with just a few seconds to drain. If you do drown it, of course you have to turn it upside down to get the engine water out through the spark plug hole, drain the carb and flush it with some gas, then put in a new plug and go. Think before you get off in deep water. It is always easier to stay out of trouble than to get out of trouble.