The water pump cover is the lowest point in the cooling system for all my dirt/adventure motorcycles. Therefore, I was unaware of the different design for your street bike.
I think you are following the best procedure to eliminate any air voids in the cooling system.
If necessary, keep adding coolant until the radiators won't accept any more.
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Spud
"Never argue with an idiot. He will drag you down to his level, and beat you with experience."
Mark Twain
2015 Zongshen ZS250GY-3 (RX3)
2006 Zongshen ZS200GY-2 (Sierra 200)
2005 Honda XR650L
2004 Honda CRF250X
1998 Kawasaki KDX220
Mods made to my Zongshen ZS200GY-2:
http://www.chinariders.net/showthread.php?t=6894