I'm not sure if my RX3 has that bracket. If my bike does have the bracket, it doesn't obstruct access to the air box cover. The wiring harness should be routed above the air box cover, following the outside edge of the frame.
I suggest you might remove one inch from the end of the strap. Then re-bend the strap into a 'U' which is located in a higher position, nearer the upper side rail of the frame. You can then route the wiring harness through the loop, and the wiring harness will be above the air box cover.
You should support the rest of the wiring harness with zip ties. Of course, you can remove the bracket entirely, and support the entire wiring harness with zip ties.
__________________
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