I just bought a 00' Honda and I have been having problems with it..The main problem is that everytime I go riding I get water in my oil..I took it back to the place I got it and asked them about it and they said I was riding in to deep of water..But most of my friends have the same 4-wheeler and do the same things I do so I know thats not it..I was wondering if anyone may know what the problem is.

 

You didnt say if you have any problem with the way it runs or how deep of water you are talking about so I assume that it is not getting in thru the airbox. This is just a general list of what to look for.
First thing to check is the crankcase breather tube. It usually comes out of the engine case on the rear just below the carb. Follow it up and make sure it is not disconnected or cut. Also make sure the dipstick has the rubber o-ring on it too.
If you ARE having problems with water getting in the airbox make sure the small drain tube on the bottom of the airbox is not missing. And also that the airbox cover is on right and clips are fastened. One of these are usually the most common things you will find causing the problem.
Let us know what you find!