Motorcycle Repair: 2002 suzuki marauder vz800, 2002 suzuki marauder, coolant tank

Question
This is a liquid cooled bike with a reserve coolant tank however this tank is completely sealed and empty how do I fill my coolant? Do I just fill it from the coolant cap because I tried this and the coolant would not go down  and or is there some magical way to fill the reserve

Another question I just recently noticed the previous owner removed the right side air filter and housing I have not noticed anything wrong with the way it runs and bike has a lot of power do you know why some one would do this and do you believe it will effect the bike in the future

Answer
The reservior is kind of a overflow tank if the bike overheats and the coolant is under pressure to get to the tank via small hose into the bottom of tank the top of the tank is vented to atmosphere. Its not really a reseve tank, but the cap and radiator system has a way to pull the coolant back out of tank when it cools down. The other qustion about the air filter puzzels me. There is no beneficial reason to remove the right air cleaner assembly unless its there for a fake reason to loog good but has no actual function.Some bikes have a fake filter housing on one side to look good. It could have fallen over and got broken so it was removed to hide the damage. The other concern would be unfiltered air going into the intake system giving you another set of problems.