It's one of those things that KDXs do. Simply try leaving the tank empty for a ride. It's an overflow accumulator so it doesn't need any coolant to start out. IF you have one of the Lucky 220s that don't overheat, the coolant will go right back into the radiator after the system cools. For some reason any extra coolant added to those tanks disappears. If you find the bike overheating this summer go to www.evanscooling.com and get their NGP+ - It is the only solution we've found for the chronic overheating that actually works.