I got the Dremel out last night, stuffed the air box full of t-shirts (because I'm too lazy to take it off), and went to hack out that plastic restrictor piece. Just before I started cutting, I realized what that piece might be there for. It very well may block liquids and other crap from getting in, but it also may control how the air flows into the carbs. Without that piece there, it looks as if 90% of the air flowing in would go strait into the front carb, leaving the rear starving for air. With the piece there, the air is directed up above the filter housing, which allows it to be inducted along the sides of the filter, instead of strait in the front (the top of the filter housing is sealed). This would spread the air evenly to both carbs. One may be able to jet up the front carb, but even so, you will still be losing air to the rear. Just a thought...

 

since cutting out that baffle i have put about 70miles on it with no problems. it has been extremely wet where i ride about 90% of those miles were put on in sloppy mud/creek crossings without a complaint from my 650. i could also feel a little more "seat of the pants" performance

 

I understand that water may not be an issue. I am also fully snorkeled, so I am not worried about water either. What I don't like is the idea that 90% of the air is probably going to the front carb. 50/50 power from both cylinders will run much stronger than a 80/20 ratio (I have no clue what the actual power ratio between cylinders is, so don't quote me on that one!). I will not be doing this modification unless someone can tell me different.

 

I did this and am totally satisfied with the results. I also left 1" of material just to catch water if needed. I still removed 2". I think the air will be evenly distributed between both carbs. I also made a few other mods to my airbox.