got a 04 400 rancher and really like it. all stock except for tires and I have cliped the carb spring and lowered the c clip on the metering rod, (this made a great difference)

Question is on the rear of the air box is a "subchamber" What does it do and do I need to do away with it when I snorkel the bike?

Thanks for any thoughts.

 

That chamber is meant for when you get water in your air box. It gives it a place to go instead of going right into your engine. I think this is what your asking about, but I might be wrong.